Question

4) Consider the following unbalanced equation. How many molecules of O2 will be required

to produce 1.60 mol of water?

H2 + O2 a? H2O

a. 4.82

Answer 1

1. 2 C6H6 + 15 O2 ----> 12 CO2 + 6 H2O

Look at your balanced equation above. Can you see that the number of moles of CO2 produced is exactly TWICE the number of moles of H2O produced? So if you have 6 moles of H2O you will get 12 moles of CO2 or if you had 10 moles of H2O you would get 20 moles of CO2 and so on.

So if you have 8.9 moles of H2O then you would get 2 x 8.9 or 17.8 moles of CO2.

2.  (1 mol CaO/ 1)(1 mol H2O/ 1 mol CaO)(18.02 g H2O/ 1 mol H2O) = 18.02 g H2O

hence ans. is c ) 18.0 g

3. Balanced equation first.

2H2 + O2 -> 2H2O

0.600 moles H2 (1 mole O2/2 moles H2)(6.022 X 10^23/1 mole O2)

= 1.81 X 10^23 molecules of O2 required hence ans. is C

------------------------------------------------------

10. The equation tells you at that twice the number of moles of HCl are produced.
So 3 moles of H2 give 6 moles HCl
Molar mass HCl = 36.5g
So 6 x 36.5g =219 g HCl produced. hence ans. s D

9.  To find out the number of moles of Cl2 consumed, we must use stoichiometrical conversions using the equation.

0.500 mol AlCl3 (3 mol Cl2/2 mol AlCl3) = 0.750 mol Cl2 hence ans. is C

8. 2C3H6 + 9O2 --> 6CO2 + 6H2O

Ratio is 2:6 between C3H6 and CO2.

? Moles (C3H6) = 4.11 x (2/6) = 1.37 mol (2 dp) hence ans. is (a)

7.
The molar mass of oxygen can be found in the periodic table. The molar mass of oxygen is 16 g/mol.
BUT because oxygen is diatomic we must multiply this value by two. We get 32 g/mol.

n= 3.0 mol
From the equation we see that there are 5 moles of oxygen per 3 moles of carbon dioxide!

Multiply 3.0 mol Oxygen x (3 mol Carbon Dioxide)/(5 mol Oxygen) =

9/5 = 1.80 mol ans. is (a)

6. Since 4 moles of aluminum are required to produce 2 moles of Al2O3, the number of moles of reactant is double the moles of the product. Therefore, 0.800 moles Al will yield 0.400 moles Al2O3.

It's 0.800 moles. hence ans. is (b)

5. (3.01 x 10^23 molecules Cl2) / (6.022 x 10^23 molecules/mol) x (2 mol NaI / 1 mol C) x
(149.894 g NaI/mol) = 150 g NaI
so answer c)

4. The formula for Oxygen gas is O2, and the formula for water is H2O.

Each molecule of Oxygen gas can produce 2 molecules of water (with enough Hydrogen, of course).

So,0.800 moles of Oxygen gas would be required to produce 1.60 moles of water.

0.80 mol X 6.023 x 10^23 molecules = 4.82 x 10^23 molecules ans. is (a)

hence ans. is d) 0.800 moles