1)массовая доля кальция в соединении равна 40%, углерода-12% кислорода-48%. выведите формулу данного соединения.

2)объемная доля кислорода в воздухе равна 21%. какой объем воздуха необходим для получения 35 л кислорода?

3) в 180г волы расстворили 20 г сахара. определите массовую долю сахарав полученном расстворе.

4) при выпаривании 80 г расствора получили 4 г соли. определите массовую долю вещества в исходном расстворе.

5) массовая доля примесей в известняке составляет 8%. найдите массу примесей в 350 г известняка.

C2H2+O2 стрелочка CO2+H2O помогите решить с объяснением

Checks and Balances The Constitution provides for three main branches of government which are separate and distinct from one another. The powers given to each are carefully balanced by the powers of the other two. Each branch serves as a check on the others. This is to keep any branch from gaining too much power or from misusing its powers. The chart 20 below illustrates how the equal branches of government are connected and how each is dependent on the other two. Congress has the power to make laws, but the President may veto any act of Congress. Congress, in its turn, can override a veto by a two-thirds vote in each house. Congress can also refuse to provide funds requested by the President. The President can appoint important officials of his administration, but they must be approved by the Senate. The President also has the power to name all federal judges; they, too, must be approved by the Senate. The courts have the power to determine the constitutionality of all acts of Congress and of presidential actions, and to strike down those they find unconstitutional. The system of checks and balances makes compromise and consensus necessary. Compromise is also a vital aspect of other levels of government in the United States. This system protects against extremes. It means, for example, that new presidents cannot radically change governmental policies just as they wish. In the U.S., therefore, when people think of "the government," they usually mean the entire system, that is, the Executive Branch and the President, Congress, and the courts. In fact and in practice, therefore, the President (i.e. "the Administration") is not as powerful as many people outside the U.S. seem to think he is. In comparison with other leaders in systems where the majority party forms "the government," he is much less so.

напиши вторую форму глаголов .                                                                                                   Exampie : work -worked                                                                                                                     finish,ask  ,answer , listen , like , collect,  walk ,stidy , smile , ski , talk,  look.        

упростите выражение (5+b)^2 - (b^2-2b+1) , найдите его значение при b=0,25