当前位置：
＞＞＞工业制硫酸的核心反应是：2SO2(g)+O2(g)2SO3(g)ΔH＜0，回答下列问题..
工业制硫酸的核心反应是 ：2SO2(g)+ O2(g)2SO3(g) ΔH＜0，回答下列问题：（1）此反应的平衡常数表达式为K=_______________，随着温度的升高，上述平衡常数_______（填“增大”、“减小”或“不变”）。 （2）将一定量的SO2(g)和O2(g)放入1 L密闭容器中，在一定条件下达到平衡，测得SO2为0.11 mol，O2为0.05 mol，SO3为0.12 mol。计算该条件下，SO2转化为SO3转化率=_________。（结果保留一位小数）（3）体积不变的条件下，下列措施中有利于提高SO2的转化率的是_____________（填字母）。A．通入氧气 B．移出氧气 C．增大压强 D．减小压强 E．加入催化剂（4）工业制硫酸的尾气中含有少量SO2 ，可用氨水吸收。反应的化学方程式为________________________________。
题型：填空题难度：中档来源：0111
（1）K= ；减小 （2）52.2% （3）A、C （4）SO2 + NH3+H2O = NH4HSO3 或 SO2 + 2NH3+H2O = (NH4)2SO3
马上分享给同学
据魔方格专家权威分析，试题“工业制硫酸的核心反应是：2SO2(g)+O2(g)2SO3(g)ΔH＜0，回答下列问题..”主要考查你对&&化学平衡的有关计算，二氧化硫，化学平衡常数，影响化学平衡的因素&&等考点的理解。关于这些考点的“档案”如下：
现在没空？点击收藏，以后再看。
因为篇幅有限，只列出部分考点，详细请访问。
化学平衡的有关计算二氧化硫化学平衡常数影响化学平衡的因素
化学平衡计算的一般思路和方法：有天化学平衡的计算一般涉及各组分的物质的量、浓度、转化率、百分含量，气体混合物的密度、平均摩尔质量、压强等。通常的思路是写出反应方程式，列出相关量(起始量、变化量、平衡量)，确定各量之间的火系，列出比例式或等式或依据平衡常数求解，这种思路和方法通常称为“三段式法”、如恒温恒压下的反应mA(g)+nB(g)pC(g)+ qD(g) (1)令A、B的起始物质的量分别为amol，bmol 达到平衡后，A的消耗量为m·xmol，容器容积为VL。则有：(2)对于反应物，对于生成物(3)(4)A的转化率(5)平衡时A的体积（物质的量）分数(6)(7)(8)二氧化硫:①化学式：SO2②分子结构：SO2是由极性键形成的极性分子，因此易溶于水，其晶体为分子晶体。二氧化硫的物理性质和化学性质：
1.物理性质： SO2是无色、有刺激性气味的有毒气体，密度比空气大，易溶于水(常温常压下，1体积水大约溶解40体积的SO2)，易液化(沸点-10℃)。 2.化学性质 (1)具有酸性氧化物的通性 ①将SO2通入紫色石蕊试液中，试液变红。 ②能与碱性氧化物、碱及某些盐反应。如：&(2)还原性 (3)弱氧化性 (4)漂白性(不能漂白酸碱指示剂) 能和某些有色物质化合生成无色物质，生成的无色物质不稳定，易分解而恢复原色，因此，SO2的漂白并不彻底。在中学化学常见试剂中，能用SO2漂白的只有品红溶液，品红溶液无色溶液恢复原色。SO2与一些物质反应的实验现象：
SO2与强碱反应后固体成分的确定：
SO2与强碱(如NaOH)溶液发生反应后的固体成分取决于二者的用量。遇到类似的问题，可以采用数轴分析法讨论。设SO2的物质的量为n(SO2)，NaOH物质的量为n(NaOH)，数轴代表，如下数轴所示：分析数轴可得：（1）则固体物质为Na2SO3，（2），则固体物质为NaOH 和Na2SO3．（3），则同体物质为NaHSO3（4），则固体物质为Na2SO3和NaHSO3，（5），则固体物质为NaHSO3。二氧化硫的制备：工业制法： 实验室制法：(1)收集：向上排空气法。 (2)检验：品红溶液。SO2是中学阶段学到的唯一种既能使品红褪色，加热后又能使其恢复原色的气体。 (3)尾气处理：用NaOH溶液吸收。 二氧化硫的用途：工业上用二氧化硫漂白纸浆、毛、丝、草编制品等。此外，二氧化硫还可用于杀菌消毒，可以用作防腐剂。 二氧化硫对环境的污染及治理：定义：在一定温度下，可逆反应无论从正反应开始，还是从逆反应开始，也不管反应物起始浓度大小，最后都达到平衡，这时各生成物浓度的化学计量数次幂的乘积除以各反应物浓度的化学计量数次幂的乘积所得的比值是个常数，用K表示，这个常数叫化学平衡常数。化学表平衡达式：对于可逆反应mA(g)+nB(g)pC(g)+qD(g)来说，化学平衡表达式：化学平衡常数的意义：①表示该反应在一定温度下，达到平衡时进行的程度，K值越大，正反应进行的越彻底，对反应物而言转化率越高。 ②某一温度下的K′与K比较能够判断反应进行的方向 K′&K，反应正向进行；K′&K，反应逆向进行；K′=K，反应处于平衡状态 (3)化学平衡常数与浓度、压强、催化剂无关，与温度有关，在使用时必须指明温度。 (4)在计算平衡常数时，必须是平衡状态时的浓度。 (5)对于固体或纯液体而言，其浓度为定值，可以不列入其中。 (6)化学平衡常数是指某一具体反应的平衡常数，若反应方向改变，则平衡常数改变，且互为倒数关系。如：在一定温度下，化学平衡常数的应用： 1．K值越大，说明平衡体系中生成物所占的比例越大，正向反应进行的程度越大，反应物转化率越大；反之，正向反应进行的程度就越小，反应物转化率就越小，即平衡常数的大小可以衡量反应进行的程度，判断平衡移动的方向，进行平衡的相关计算。 2．若用浓度商(任意状态的生成物浓度幂之积与反应物浓度幂之积的比值，符号为Qc)与K比较，可判断可逆反应是否达到平衡状态和反应进行的方向。 3．利用K值可判断反应的热效应若升高温度，K值增大，则正反应为吸热反应；若升高温度，K值减小，则正反应为放热反应。 4．计算转化率及浓度依据起始浓度(或平衡浓度)和平衡常数可以计算平衡浓度(或起始浓度)，从而计算反应物的转化率。影响化学平衡的因素：(1)浓度在其他条件不变的情况下，增大反应物的浓度或减小生成物的浓度，都可以使化学平衡向正反应方向移动；增大生成物的浓度或减小反应物的浓度，都可以使化学平衡向逆反应方向移动。 (2)压强对反应前后气体总体积发生变化的反应，在其他条件不变时，增大压强会使平衡向气体体积缩小的方向移动，减小压强会使平衡向气体体积增大的方向移动。对于反应来说，加压，增大、增大，增大的倍数大，平衡向正反应方向移动：若减压，均减小，减小的倍数大，平衡向逆反应方向移动，加压、减压后v一t关系图像如下图：&(3)温度在其他条件不变时，温度升高平衡向吸热反应的方向移动，温度降低平衡向放热反应的方向移动对于，加热时颜色变深，降温时颜色变浅。该反应升温、降温时，v—t天系图像如下图：(4)催化剂由于催化剂能同等程度地改变正、逆反应速率，所以催化剂对化学平衡无影响，v一t图像为稀有气体对化学反应速率和化学平衡的影响分析：1．恒温恒容时充入稀有气体体系总压强增大，但各反应成分分压不变，即各反应成分的浓度不变，化学反应速率不变，平衡不移动。 2．恒温恒压时 充入稀有气体容器容积增大各反应成分浓度降低反应速率减小，平衡向气体体积增大的方向移动。3．当充入与反应无关的其他气体时，分析方法与充入稀有气体相同。化学平衡图像：1．速率一时间因此类图像定性揭示了随时间(含条件改变对化学反应速率的影响)变化的观律，体现了平衡的“动、等、定、变”的基本特征，以及平衡移动的方向等。&2．含量一时间一温度(压强)图常见的形式有下图所示的几种(C％指某产物百分含量，B％指某反应物百分含量)，这些图像的折点表示达到平衡的时间，曲线的斜率反映了反应速率的大小，可以确定T(p)的高低(大小)，水平线高低反映平衡移动的方向。3．恒压(温)线该类图像的纵坐标为物质的平衡浓发(c)或反应物的转化率(α)，横坐标为温度(T)或压强 (p)，常见类型如下图：小结：1．图像分析应注意“三看” (1)看两轴：认清两轴所表示的含义。 (2)看起点：从图像纵轴上的起点，一般可判断谁为反应物，谁为生成物以及平衡前反应进行的方向。 (3)看拐点：一般图像在拐点后平行于横轴则表示反应达平衡，如横轴为时间，由拐点可判断反应速率。 2．图像分析中，对于温度、浓度、压强三个因素，一般采用“定二议一”的方式进行分析平衡移动方向与反应物转化率的关系:1．温度或压强改变引起平衡向正反应方向移动时，反应物的转化率必然增大。 2．反应物用量的改变 (1)若反应物只有一种时，如aA(g)bB(g)+ cc(g)，增加A的量，平衡向正反应方向移动，但反应物 A的转化率与气体物质的化学计量数有关：&(2)若反应物不止一种时，如aA(g)+bB(g)cC(g)+dD(g)： a．若只增加A的量，平衡向正反应方向移动，而A的转化率减小，B的转化率增大。 b．若按原比例同倍数的增加反应物A和B的量，则平衡向正反应方向移动，而反应物的转化率与气体物质的计量数有关：&c．若不同倍增加A、B的量，相当于增加了一种物质，同a。 3．催化剂不改变转化率。 4．反应物起始的物质的量之比等于化学计量数之比时，各反应物转化率相等。浓度、压强影响化学平衡的几种特殊情况:1．当反应混合物中存在固体或纯液体物质时，由于其“浓度”是恒定的，不随其量的增减而变化，故改变这些固体或纯液体的量，对平衡基本无影响。 2．南于压强的变化对非气态物质的浓度基本无影响，因此，当反应混合物中不存在气态物质时，压强的变化对平衡无影响。 3．对于气体分子数无变化的反应，如，压强的变化对其平衡无影响。这是因为，在这种情况下，压强的变化对正、逆反应速率的影响程度是等同的，故平衡不移动。 4．对于有气体参加的反应，同等程度地改变反应混合物中各物质的浓度，应视为压强对平衡的影响，如某平衡体系中，，，当浓度同时增大一倍时，即让，此时相当于压强增大一倍，平衡向生成NH3的方向移动。 5．在恒容的密闭容器中，当改变其中一种气体物质的浓度时，必然同时引起压强改变，但判断平衡移动的方向时，心仍从浓度的影响去考虑：如，平衡后，向容器中再通入反应物，使 c(NO2)增大，平衡正向移动；如向容器中再通入生成物 N2O4，则使c(N2O4)增大，平衡逆向移动。但由于两种情况下，容器内的压强都增大，故对最终平衡状态的影响是一致的，如两种情况下，重新达到平衡后，NO2的百分含量都比原平衡时要小
发现相似题
与“工业制硫酸的核心反应是：2SO2(g)+O2(g)2SO3(g)ΔH＜0，回答下列问题..”考查相似的试题有：
370394321129349004329913103925367940√4-√9= - 叫阿莫西中心 - 中国网络使得骄傲马戏中心！
<div id="post_(2x-3)^2=4(2-x)^2_百度知道
9(2x-3)^2=4(2-x)^2
提问者采纳
9(2x-3)^2=4(2-x)^29(2x-3)^2-4(2-x)^2=0(4X-5)(8X-13)=0X=5/4，X=13/8
其他类似问题
其他5条回答
9(2x-3)^2=4(2-x)^2[3(2x-3)]^2-[2(x-2)]^2=0(6x-9)^2-(2x-4)^2=0(6x-9+2x-4)(6x-9-2x+4)=0(8x-13)(4x-5)=0x=13/8,x=5/4
解：9(2x-3)^2=4(2-x)^2 (6x-9)&sup2;-(4-2x)&sup2;=0(6x-9+4-2x)(6x-9-4+2x)=0(4x-5)(8x-13)=0x1=5/4,x2=13/8
（9（2x-3）^2）-(4（2-x）^2)=0(3(2x-3)+2(2-x))(3(2x-3)-2(2-x))=0(6x-9+4-2x)(6x-9-4+2x)=0(4x-5)(8x-13)=0x=5/4x=13/8
(3*(2x-3)^2=(2*(2-x)^23*(2x-3)=2*(2-x) or 3*(2x-3)= - 2*(2-x)6x-9=4-2x or 6x-9=-4+2x8x=13
or 4x = 5x=13/8 or x=5/4
9(2x-3)^2=4(2-x)^2 9(2x-3)^2-4(2-x)^2=0[3 (2x-3)+2(2-x)][3 (2x-3)-2(2-x)]=0(6x-9+4-2x)(6x-9-4+2x)=0(4x-5)(8x-13)=0x1=5/4x2=13/8
等待您来回答
下载知道APP
随时随地咨询
出门在外也不愁上传时间：
和龙妹妹在一起的日子
热搜风云榜
56官方微信
扫一扫发现精彩当前位置：
＞＞＞2.4×9.9+0.24=2.4×（9.9+0.1）[]-六年级数学-魔方格
2.4×9.9+0.24=2.4×（9.9+0.1）
题型：判断题难度：偏易来源：同步题
马上分享给同学
据魔方格专家权威分析，试题“2.4×9.9+0.24=2.4×（9.9+0.1）[]-六年级数学-魔方格”主要考查你对&&运算定律和简便算法&&等考点的理解。关于这些考点的“档案”如下：
现在没空？点击收藏，以后再看。
因为篇幅有限，只列出部分考点，详细请访问。
运算定律和简便算法
学习目标：1、掌握运算定律，并能运用运算定律和性质进行正确、合理、灵活的计算。2、养成良好审题习惯，提高计算能力。运算定律：
加法交换律
两个数相加，交换加数的位置，和不变。
25+14=14+25
加法结合律
三个数相加，先把前两数相加，再同第三个数相加，或者先把后两数相加，再同第一个数相加，它们的和不变。
a+b+c=a+（b+c）
20+14+36= 20+（14+36）
乘法交换律
两个数相乘，交换因数的位置，它们的积不变。
10×12=12×10
乘法结合律
三个数相乘，先把前两个数相乘，再同第三个数相乘，或者先把后两个数相乘，再同第一个数相乘，它们的积不变。
a×b×c= a×（b×c）
12×25×4= 12×（25×4）
乘法分配律
两个数的和同一个数相乘，可以把两个加数分别和这个数相乘，再把两个积相加，结果不变。
（a+b）×c= a×c+b×c
（12+15）×4= 12×4+15×4运算性质：
减法的性质
一个数连续减去几个数等于一个数减去这几个数的和
a-b-b= a-（b+c）
250-18-52= 250-（18+52）
除法的性质
一个数连续除以几个数（0除外）等于一个数除以这几个数的积
a÷b÷c= a÷（b×c）
180÷4÷25= 180÷（4×25）
发现相似题
与“2.4×9.9+0.24=2.4×（9.9+0.1）[]-六年级数学-魔方格”考查相似的试题有：
7八年级数学期末试卷&#40;4&#41;!9 八年级数学期末试卷&#40;4&#41;!9 八年级数学期..
扫扫二维码，随身浏览文档
手机或平板扫扫即可继续访问
八年级数学期末试卷&#40;4&#41;!9
举报该文档含有违规或不良信息。
反馈该文档无法正常浏览。
举报该文档为重复文档。
推荐理由：
将文档分享至：
分享完整地址
文档地址：
粘贴到BBS或博客
flash地址：
支持嵌入FLASH地址的网站使用
html代码：
&embed src='/DocinViewer-4.swf' width='100%' height='600' type=application/x-shockwave-flash ALLOWFULLSCREEN='true' ALLOWSCRIPTACCESS='always'&&/embed&
450px*300px480px*400px650px*490px
支持嵌入HTML代码的网站使用
您的内容已经提交成功
您所提交的内容需要审核后才能发布，请您等待！
3秒自动关闭窗口GCC 4.9.0 发布，提升 C++11 和 C++14 特性
GCC 4.9.0 发布，此版本是个主要版本更新，包括了 GCC 4.8.x 系列和之前的 GCC 版本都没有的新特性，新特性非常之多。下载地址：警告移除 mudflap 运行时检查器，mudflap 选项保留，但没有任何效果.对一些很多老的系统和一些不维护的平台的支持在 4.9 版本中声明为过世的，下一个版本将永久删除，例如 Solaris 9更多移植到& GCC 4.9 的信息请参考 一般优化器改进AddressSanitizer, a fast memory error detector, is now available on ARM.UndefinedBehaviorSanitizer (ubsan), a fast undefined behavior detector,
& & & &has been added and can be enabled via -fsanitize=undefined.
Various computations will be instrumented to detect undefined behavior
at runtime. &UndefinedBehaviorSanitizer is currently available for the C
and C++ languages.Link-time optimization (LTO) improvements:Memory usage building Firefox with debug enabled was reduced from 15GB to
& &3.5GB; link time from 1700 seconds to 350 seconds.Type merging was rewritten. The new implementation is significantly faster
& & &and uses less memory.Better partitioning algorithm resulting in less streaming during
&link time.Early removal of virtual methods reduces the size of object files and
&improves link-time memory usage and compile time.Function bodies are now loaded on-demand and released early improving
&overall memory usage at link time.C++ hidden keyed methods can now be optimized out.When using a linker plugin, compiling with the -flto
& & & & &option now generates slim objects files (.o) which only
& & & & &contain intermediate language representation for LTO. Use & & & & &-ffat-lto-objects to create files which contain
& & & & &additionally the object code. &To generate static libraries suitable
& & & & &for LTO processing, use gcc-ar and & & & & gcc- to list symbols from a slim object file use & & & & gcc-nm. (Requires that ar, & & & & ranlib and nm have been compiled with
& & & & plugin support.)Inter-procedural optimization improvements:New type inheritance analysis module improving devirtualization.
&Devirtualization now takes into account anonymous name-spaces and the
&C++11 final keyword.New speculative devirtualization pass (controlled by
&-fdevirtualize-speculatively.Calls that were speculatively made direct are turned back to indirect
&where direct call is not cheaper.Local aliases are introduced for symbols that are known to be
&semantically equivalent across shared libraries improving dynamic
&linking times.Feedback directed optimization improvements:Profiling of programs using C++ inline functions is now more reliable.New time profiling determines typical order in which functions are
&executed.A new function reordering pass (controlled by
&-freorder-functions) significantly reduces
&startup time of large applications. &Until binutils support is
&completed, it is effective only with link-time optimization.Feedback driven indirect call removal and devirtualization now handle
&cross-module calls when link-time optimization is enabled.新语言和语音特性改进Version 4.0 of the
is now supported for the C and C++ compilers.
The new -fopenmp-simd option can be used to enable OpenMP&#39;s
SIMD directives, while ignoring other OpenMP directives. The new
option permits to tune the
vectorization cost model for loops annotated with OpenMP and Cilk
Plus simd -Wopenmp-simd warns when
the current costmodel overrides simd directives set by the user.The -Wdate-time option has been added for the C, C++ and
Fortran compilers, which warns when the __DATE__, __TIME__ or __TIMESTAMP__ macros are used.
Those macros might prevent bit-wise-identical reproducible
compilations.AdaGNAT switched to Ada 2012 instead of Ada 2005 by default.C familySupport for colorizing diagnostics emitted by GCC has been added.
will enable it when
& &outputting to terminals, -fdiagnostics-color=always
& &unconditionally. &The GCC_COLORS environment variable
& &can be used to customize the colors or disable coloring.
& &If GCC_COLORS variable is present in the environment,
& &the default is -fdiagnostics-color=auto, otherwise & &-fdiagnostics-color=never.
& &Sample diagnostics output:&&&&$&g++&-fdiagnostics-color=always&-S&-Wall&test.C&&&&test.C:&In&function&‘int&foo()’:&&&&test.C:1:14:&warning:&no&return&statement&in&function&returning&non-void&[-Wreturn-type]
&&&&&int&foo&()&{&}&&&&&&&&&&&&&&&&&&^
&&&&test.C:2:46:&error:&template&instantiation&depth&exceeds&maximum&of&900&(use&-ftemplate-depth=&to&increase&the&maximum)&instantiating&‘struct&X&100&’
&&&&&template&&int&N&&struct&X&{&static&const&int&value&=&X&N-1&::&};&template&struct&X&1000&;&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&^
&&&&test.C:2:46:&&&recursively&required&from&‘const&int&X&999&::value’&&&&test.C:2:46:&&&required&from&‘const&int&X&1000&::value’&&&&test.C:2:88:&&&required&from&here&&&&test.C:2:46:&error:&incomplete&type&‘X&100&’&used&in&nested&name&specifierWith the new , the user can assert that there are no
& &loop-carried dependencies which would prevent concurrent execution of
& &consecutive iterations using SIMD (single instruction multiple data)
& &instructions.Support for
& &added and can be enabled with the -fcilkplus option. &Cilk Plus
& &is an extension to the C and C++ languages to support data and task
& &parallelism. &The present implementation follows ABI version 1.2; all
& &features but _Cilk_for have been implemented.CISO C11 atomics (the _Atomic type specifier and
&qualifier and the &stdatomic.h& header) are now
&supported.ISO C11 generic selections (_Generic keyword) are
&now supported.ISO C11 thread-local storage (_Thread_local,
&similar to GNU C __thread) is now supported.ISO C11 support is now at a similar level of completeness to ISO
&C99 support: substantially complete modulo bugs, extended
&identifiers (supported except for corner cases
&when -fextended-identifiers is used), floating-point
&issues (mainly but not entirely relating to optional C99 features
&from Annexes F and G) and the optional Annexes K (Bounds-checking
&interfaces) and L (Analyzability).A new C extension __auto_type provides a subset of
&the functionality of C++11 auto in GNU C.C++The G++ implementation of
return type deduction for normal
& &functions has been updated to conform to & &,
& &the proposal accepted into the working paper. &Most notably, it adds decltype(auto) for
& &getting decltype semantics rather than the template argument deduction semantics of plain auto:int&&f();
&&&&&&&&&auto&&i1&=&f();&//&int
decltype(auto)&i2&=&f();&//&int&G++ supports
lambda capture initializers:[x&=&42]{&...&};Actually, they have been accepted since GCC 4.5, but now the compiler doesn&#39;t
warn about them with -std=c++1y, and supports parenthesized and
brace-enclosed initializers as well.G++ supports
variable length
& &arrays. &G++ has supported GNU/C99-style VLAs for a long time, but now
& &additionally supports initializers and lambda capture by reference. &In
& &C++1y mode G++ will complain about VLA uses that are not permitted by
& &the draft standard, such as forming a pointer to VLA type or
& &applying sizeof to a VLA variable. &Note that it now appears
& &that VLAs will not be part of C++14, but will be part of a separate
& &document and then perhaps C++17.void&f(int&n)&{
&&int&a[n]&=&{&1,&2,&3&};&//&throws&std::bad_array_length&if&n&&&3
&&[&a]{&for&(int&i&:&a)&{&cout&&&&i&&&&&}&}();
&&&a;&//&error,&taking&address&of&VLA
}G++ supports the
[[deprecated]]
& &attribute modulo bugs in the underlying [[gnu::deprecated]] attribute. &Classes
& &and functions can be marked deprecated and a diagnostic message added:class&A;
int&bar(int&n);
#if&__cplusplus&&&201103
class&[[deprecated(&A&is&deprecated&in&C++14;&Use&B&instead&)]]&A;
[[deprecated(&bar&is&&use&foo()&instead&)]]
int&bar(int&n);
int&foo(int&n);
A&&//&warning:&&#39;A&#39;&is&deprecated&:&A&is&deprecated&in&C++14;&Use&B&instead
int&j&=&bar(2);&//&warning:&&#39;int&bar(int)&#39;&is&deprecated&:&bar&is&&use&foo()&insteadG++ supports
digit separators.
& &Long numeric literals can be subdivided with a single quote &#39; to enhance readability:int&i&=&1048576;
int&j&=&1&#39;048&#39;576;
int&k&=&0x10&#39;0000;
int&m&=&0&#39;004&#39;000&#39;000;
int&n&=&0b0&#39;0&#39;0;
double&x&=&1.602&#39;176&#39;565e-19;
double&y&=&1.602&#39;176&#39;565e-1&#39;9;G++ supports
polymorphic lambdas.//&a&functional&object&that&will&increment&any&type
auto&incr&=&[](auto&x)&{&return&x++;&};Runtime Library (libstdc++), including:support for &regex&;The associative containers in &map& and & & & & & & &&set& and the unordered associative containers
& & & & & & &in &unordered_map& and &unordered_set&
& & & & & & &meet the allocator-aware co,
& & & including:fixing constexpr member funimplementation of the std::exchange()addreimplemention of std::make_implemention of std::shared_making std::result_of SFINAE-adding operator() to integral_adding user-defined literals for standard library types & & & & & & std::basic_string, std::chrono::duration,
& & & & & & and std::adding two range overloads to non-modifying sequence oprations & & & & & & std::equal and std::adding IO manipulatoradding constexpr members to &utility&, & & & & & & &complex&, &chrono&,adding compile-time std::integer_adding cleaner tmaking &functional&s operator functors easier to use
& & & & & &An implementation of std::experimental::optional.An implementation of std::experimental::string_view.The non-standard function std::copy_exception has been deprecated
& & & &and will be removed in a future version. std::make_exception_ptr
& & & &should be used instead.FortranCompatibility notice:Note that the
has changed for scalar dummy
&arguments of type INTEGER, REAL,
&COMPLEX and LOGICAL, which have
&both the VALUE and the OPTIONAL
&attribute.Due to the support of finalization, the virtual table associated
& & & & &with polymorphic variables has changed. Therefore, code containing & & & & &CLASS should be recompiled, including all files which
& & & & &define derived types involved in the type definition used by
& & & & &polymorphic variables. (Note: Due to the incremented module version,
& & & & &trying to mix old code with new code will usually give an error
& & & & &message.)Module files: The version of the module files (.mod)
& & & & additionally, module files are now compressed.
& & & &Fortran MODULEs compiled by earlier GCC versions have
& & & &to be recompiled, when they are USEd by files compiled
& & & &with GCC 4.9, because GCC 4.9 is not able to read .mod
& & & &files of earlier GCC attempting to do so gives an error
& & & &message. Note: The ABI of the produced assembler data itself has not
& & & &changed: object files and libraries are fully compatible to older
& & & &versions. (Except for the next items.)ABI changes:GNU Fortran no longer deallocates allocatable variables or
& & & &allocatable components of variables declared in the main program. Since
& & & &Fortran 2008, the standard explicitly states that variables declared
& & & &in the Fortran main program automatically have the SAVE
& & & &attribute.When opening files, the close-on-exec flag is set if the system
& & & &supports such a feature. This is generally considered good practice
& & & &these days, but if there is a need to pass file descriptors to child
& & & &processes the parent process must now remember to clear the
& & & &close-on-exec flag by calling fcntl(), e.g. via & & & &ISO_C_BINDING, before executing the child process.The deprecated command-line option -fno-whole-file
& & &has been removed. (-fwhole-file is the default since
& & &GCC 4.6.) -fwhole-file/-fno-whole-file
& & &continue to be accepted but do not influence the code generation.The compiler no longer unconditionally warns
& & &about DO loops with zero iterations. &This warning is now
& & &controlled by the -Wzerotrips option, which is implied by & & &-Wall.The new NO_ARG_CHECK attribute of the
can be used to disable the
& & &type-kind-rank (TKR) argument check for a dummy argument. The feature
& & &is similar to ISO/IEC TS &#39;s TYPE(*), except that
& & &it additionally also disables the rank check. Variables with & & &NO_ARG_CHECK have to be dummy arguments and may only be
& & &used as argument to ISO_C_BINDING&#39;s C_LOC
& & &and as actual argument to another NO_ARG_CHECK dummy
& & & also the other constraints of TYPE(*) apply.
& & &The dummy arguments should be declared as scalar or assumed-size
& & &variable of type type(*) (recommended) – or of
& & &type integer, real, complex
& & &or logical. With NO_ARG_CHECK, a pointer
& & &to the data without further type or shape information is passed,
& & &similar to C&#39;s void*. Note that also TS 29113&#39;s & & &type(*),dimension(..) accepts arguments of any type and
& & & contrary to NO_ARG_CHECK assumed-rank arguments
& & &pass an array descriptor which contains the array shape and stride
& & &of the argument.:Finalization is now supported. Note that finalization is currently
& & & &only done for a subset of the situations in which it should occur.Experimental support for scalar character components with
& & & &deferred length (i.e. allocatable string length) in derived types has
& & & &been added. (Deferred-length character variables are supported since
& & & &GCC 4.6.):When STOP or ERROR STOP is used to terminate
& & & &the execution and any exception (but inexact) is signaling, a warning is
& & & &printed to ERROR_UNIT, indicating which exceptions are
& & & &signaling. The
command-line option can be used to fine-tune
& & & &for which exception the warning should be shown.Rounding on input (READ) is now handled on systems where & & & &strtod honours the rounding mode. (For output, rounding is
& & & &supported since GCC 4.5.) Note that for input, the & & & &compatible rounding mode is handled as nearest
& & & &(i.e., for a tie, rounding to an even last significant
& & & &[cf. IEC ] – while compatible rounds away
& & & &from zero for a tie).GoGCC 4.9 provides a complete implementation of the Go 1.2.1
& & &release.新平台支持AArch64The ARMv8-A crypto and CRC instructions are now supported through
& & & intrinsics. These are enabled when the architecture supports these
& & & and are available through the -march=armv8-a+crc
& & & and -march=armv8-a+crypto options.Initial support for ILP32 has now been added to the
& & & compiler. This is now available through the command line option & & & -mabi=ilp32. Support for ILP32 is
& & & considered experimental as the ABI specification is still beta.Coverage of more of the ISA including the SIMD extensions has
& & & been added. The Advanced SIMD intrinsics have also been improved.The new local register allocator (LRA) is now on by default
& & & for the AArch64 backend.The REE (Redundant extension elimination) pass has now been enabled
& & & by default for the AArch64 backend.Tuning for the Cortex-A53 and Cortex-A57 has been improved.Initial big.LITTLE tuning support for the combination of Cortex-A57
& & & and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53 & & &
option.A number of structural changes have been made to both the ARM
& & & and AArch64 backends to facilitate improved code-generation.ARMUse of Advanced SIMD (Neon) for 64-bit scalar computations has been
disabled by default. This was found to generate better code in only
a small number of cases. It can be turned back on with the -mneon-for-64bits option.Further support for the ARMv8-A architecture, notably implementing
& & & the restriction around IT blocks in the Thumb32 instruction set has
& & & been added. The -mrestrict-it option can be used with & & & -march=armv7-a or the -march=armv7ve options
& & & to make code generation fully compatible with the deprecated instructions
& & & in ARMv8-A.Support has now been added for the ARMv7ve variant of the
& & & architecture. This can be used by the -march=armv7ve option.The ARMv8-A crypto and CRC instructions are now supported through
& & & intrinsics and are available through the -march=armv8-a+crc
& & & and mfpu=crypto-neon-fp-armv8 options.LRA is now on by default for the ARM target. This can be turned off
& & & using the -mno-lra option. This option is purely
& & & transitionary command line option and will be removed in a future
& & & release. We are interested in any bug reports regarding functional and
& & & performance regressions with LRA.A new option -mslow-flash-data to improve performance
& & & of programs fetching data on slow flash memory has now been
& & & introduced for the ARMv7-M profile cores.A new option -mpic-data-is-text-relative for targets
& & & that allows data segments to be relative to text segments has
& & & been added. This is on by default for all targets except VxWorks RTP.A number of infrastructural changes have been made to both the ARM
& & & and AArch64 backends to facilitate improved code-generation.GCC now supports Cortex-A12 and the Cortex-R7 through the & & & -mcpu=cortex-a12 and -mcpu=cortex-r7 options.GCC now has tuning for the Cortex-A57 and Cortex-A53
& & & through the -mcpu=cortex-a57 and -mcpu=cortex-a53 & & &
options.Initial big.LITTLE tuning support for the combination of Cortex-A57
& & & and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53 & & &
option. Similar support was added for the combination of
& & & Cortex-A15 and Cortex-A7 through the -mcpu=cortex-a15.cortex-a7 & & &
option.Further performance optimizations for the Cortex-A15 and the
& & & Cortex-M4 have been added.A number of code generation improvements for Thumb2 to reduce code
& & & size when compiling for the M-profile processors.IA-32/x86-64-mfpmath=sse is now implied by -ffast-math
on all targets where SSE2 is supported.Intel AVX-512 support was added to GCC. &That includes inline
& & &assembly support, new registers and extending existing ones,
& & &new intrinsics (covered by corresponding testsuite), and basic
& & &autovectorization. &AVX-512 instructions are available via
& & &the following GCC switches: AVX-512 foundation instructions: & & &-mavx512f, AVX-512 prefetch instructions: -mavx512pf,
& & &AVX-512 exponential and reciprocal instructions: -mavx512er,
& & &AVX-512 conflict detection instructions: -mavx512cd.It is now possible to call x86 intrinsics from select functions in
& & &a file that are tagged with the corresponding target attribute without
& & &having to compile the entire file with the -mxxx option.
& & &This improves the usability of x86 intrinsics and is particularly useful
& & &when doing .GCC now supports the new Intel microarchitecture named Silvermont
& & &through -march=silvermont.GCC now supports the new Intel microarchitecture named Broadwell
& & &through -march=broadwell.Optimizing for other Intel microarchitectures have been renamed
& & &to -march=nehalem, westmere, & & &sandybridge, ivybridge, & & &haswell, bonnell.-march=generic has been retuned for better support of
& & &Intel core and AMD Bulldozer architectures. &Performance of AMD K7, K8,
& & &Intel Pentium-M, and Pentium4 based CPUs is no longer considered important
& & &for generic.-mtune=intel can now be used to generate code running
& & &well on the most current Intel processors, which are Haswell
& & &and Silvermont for GCC 4.9.Support to encode 32-bit assembly instructions in 16-bit format
& & &is now available through the -m16 command-line option.Better inlining of memcpy and memset
that is aware of value ranges and produces shorter alignment prologues.-mno-accumulate-outgoing-args is now honored when unwind
& & &information is output. &Argument accumulation is also now turned off
& & &for portions of programs optimized for size.Support for new AMD family 15h processors (Excavator core)
& & & &is now available through the -march=bdver4 and & & & &-mtune=bdver4 options.MSP430A new command-line option -mcpu= has been added to the MSP430 backend.
& &This option is used to specify the ISA to be used. &Accepted values are & &msp430 (the default), msp430x and msp430xv2. &The ISA is no longer deduced
& &from the -mmcu= option as there are far too many different MCU names. &The & &-mmcu= option is still supported, and this is still used to select linker
& &scripts and generate a C preprocessor symbol that will be recognised by the & &msp430.h header file.NDS32A new nds32 port supports the 32-bit architecture from Andes
& & &Technology Corporation.The port provides initial support for the V2, V3, V3m
& & &instruction set architectures.Nios IIA port for the Altera Nios II has been contributed by
& & &Mentor Graphics.PowerPC / PowerPC64 / RS6000GCC now supports Power ISA 2.07, which includes support for Hardware
& &Transactional Memory (HTM), Quadword atomics and several VMX and VSX
& &additions, including Crypto, 64-bit integer, 128-bit integer and
& &decimal integer operations.Support for the POWER8 processor is now available through the & &-mcpu=power8 and -mtune=power8 options.The libitm library has been modified to add a HTM fastpath that
& &automatically uses POWER&#39;s HTM hardware instructions when it is
& &executing on a HTM enabled processor.Support for the new powerpc64le-linux platform has been added.
& &It defaults to generating code that conforms to the ELFV2 ABI.S/390, System zSupport for the Transactional Execution Facility included with
& & &the IBM zEnterprise zEC12 processor has been added. &A set of
& & &GCC style builtins as well as XLC style builtins are provided.
& & &The builtins are enabled by default when using
& & &the -march=zEC12 option but can explicitly be
& & &disabled with -mno-htm.
& & &Using the GCC builtins also libitm supports hardware
& & &transactions on S/390.The hotpatch features allows to prepare functions for
& & &hotpatching. &A certain amount of bytes is reserved before the
& & &function entry label plus a NOP is inserted at its very
& & &beginning to implement a backward jump when applying a patch.
& & &The feature can either be enabled via command line
& & &option -mhotpatch for a compilation unit or can be
& & &enabled per function using the hotpatch
& & &attribute.The shrink wrap optimization is now supported on S/390 and
& & &enabled by default.A major rework of the routines to determine which registers
& & &need to be saved and restored in function prologue/epilogue now
& & &allow to use floating point registers as save slots. &This will
& & &happen for certain leaf function with -march=z10
& & &or higher.The LRA rtl pass replaces reload by default on S/390.RXThe port now allows to specify the RX100, RX200, and RX600 processors
& & &with the command line options -mcpu=rx100, -mcpu=rx200 and -mcpu=rx600.SHMinor improvements to code generated for integer arithmetic and code
& &that involves the T bit.Added support for the SH2A clips and clipu
& &instructions. &The compiler will now try to utilize them for min/max
& &expressions such as max (-128, min (127, x)).Added support for the cmp/str instruction through built-in
& &functions such as __builtin_strlen. &When not optimizing for
& &size, the compiler will now expand calls to e.g. strlen as an
& &inlined sequences which utilize the cmp/str instruction.Improved code generated around volatile memory loads and stores.The option -mcbranchdi has been deprecated. &Specifying it
& &will result in a warning and will not influence code generation.The option -mcmpeqdi has been deprecated. &Specifying it
& &will result in a warning and will not influence code generation.详细内容请看。
GCC 的详细介绍：
GCC 的下载地址：
想通过手机客户端（支持 Android、iPhone 和 Windows Phone）访问开源中国：
旧一篇： 7个月前
新一篇： 7个月前
相关讨论话题
你也许会喜欢
倒地还有多少新特性啊
2楼：DarkAngel
C++14 是什么时候出来的？
3楼：leoking 来自
4楼：飛羽灬
谁敢与C++一战？？？？？？
5楼：eechen
Ubuntu 14.04 上的 GCC 是 4.8.2。
6楼：卜库塔
C++貌似认定通过新特性解决以前的旧问题了，还不如甩开包袱出个精简版
引用来自“eechen”的评论Ubuntu 14.04 上的 GCC 是 4.8.2。FreeBSD 是 gcc 4.8.3
8楼：李博文
引用来自“eechen”的评论Ubuntu 14.04 上的 GCC 是 4.8.2。引用来自“冰力”的评论FreeBSD 是 gcc 4.8.3FreeBSD不是换成clang了呗
9楼：李博文
不急，还有个 4.10.x
10楼：pollex
论复杂度，现在的C++完爆任何其他语言几万条街。
11楼：冰力
引用来自“eechen”的评论Ubuntu 14.04 上的 GCC 是 4.8.2。引用来自“冰力”的评论FreeBSD 是 gcc 4.8.3引用来自“李博文”的评论FreeBSD不是换成clang了呗gcc 也可以用，现在 gcc 编译出来的性能跟 clang 差不多了，总是要借鉴的嘛，就是 gcc 自身代码质量臃肿，而且在编译的过程中慢的要死，一个大点的项目开发中，每次编译等很久，浪费开发者时间。
12楼：洪文军
正则好用了没
13楼：zp-wmhx
这个出多厚一本书才可以写清楚这些新特性.?
14楼：李博文
引用来自“eechen”的评论Ubuntu 14.04 上的 GCC 是 4.8.2。引用来自“冰力”的评论FreeBSD 是 gcc 4.8.3引用来自“李博文”的评论FreeBSD不是换成clang了呗引用来自“冰力”的评论gcc 也可以用，现在 gcc 编译出来的性能跟 clang 差不多了，总是要借鉴的嘛，就是 gcc 自身代码质量臃肿，而且在编译的过程中慢的要死，一个大点的项目开发中，每次编译等很久，浪费开发者时间。4.8.3 还没发布吧
15楼：一如当初
新特性，适合自己的就学学，不适合的就别理会。我是这样的。能应付工作就行。
16楼：newzai
g++, 动态数组， lambal 模板。。强悍啊。。功能越来越越强大。
17楼：eechen
引用来自“eechen”的评论Ubuntu 14.04 上的 GCC 是 4.8.2。引用来自“冰力”的评论FreeBSD 是 gcc 4.8.34.8.3还没有发布，你说的应该是4.7.3http://gcc.gnu.org/
18楼：你别逗
14:38 (非会员)
引用来自“eechen”的评论Ubuntu 14.04 上的 GCC 是 4.8.2。引用来自“冰力”的评论FreeBSD 是 gcc 4.8.3引用来自“李博文”的评论FreeBSD不是换成clang了呗引用来自“冰力”的评论gcc 也可以用，现在 gcc 编译出来的性能跟 clang 差不多了，总是要借鉴的嘛，就是 gcc 自身代码质量臃肿，而且在编译的过程中慢的要死，一个大点的项目开发中，每次编译等很久，浪费开发者时间。llvm可以摆上台面，至于clang，呵呵
19楼：中山野鬼
哈，搞这么多年优化，总结一条，该不该优化，优化到什么程度是要解决的重点，而不是优化的策略、方式、方法。
20楼：第五郎
引用来自“中山野鬼”的评论哈，搞这么多年优化，总结一条，该不该优化，优化到什么程度是要解决的重点，而不是优化的策略、方式、方法。还有不该优化的？
与内容无关的评论将被删除，严重者禁用帐号
本周热点资讯
本站最新资讯
说的太好了，我顶！
Copyright & 2014
Corporation, All Rights Reserved
Processed in 0.8236 second(s), 2 db_queries,
1 rpc_queries}