Please help!!



1) How many atoms are in a 12.0 g sample of carbon?

A1.74 10^23 atoms

B6.02 10^23 atoms

C1.04 10^24 atoms

D7.24 10^24 atoms

2) Given the following chemical equation:


Ag NO3 (aq) + Kl (aq) Agl(s) + KNO3 (aq)


How many grams of potassium iodide will produce 750 grams of silver iodide, when there is an excess of silver nitrate?

A235

B707g

C529.79 g

D301 g

3) what is the molecular formula of a compound that has an empirical formula of c2h5 and a molecular mass of 116 grams/mole?

AC2H5

BC4H10

CC6H15

DC8H20

4) Boron reacts with oxygen gas to form boron oxide, as shown in the reaction below:


4B(s) + 3O2(g) > 2B2O3(s)


How many grams of boron are needed to completely react with 492 g of oxygen gas?

A225.5g

B102 g

C216 g

D432 g

5) sulfuric acid is used in large quantities in petroleum refining and metallurgy as well as in the manufacture of fertilizer. If an industrial process requires 4.90 grams of H2SO4, how many molecules are in this amount?

A7.00 10^20

B3.18 10^23

C6.02 10^23

D2.11 10^23

6) what is the mass of five mole of helium gas?

A2 g

B4 g

C8 g

D20 g