Stoichiometry and Molar Masses

Question 1WRONGUnder appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia:

N2 (g) + 3 H2 (g) → 2 NH3 (g)

A 7.1 g sample of N2 requires __________ g of H2 for complete reaction.

• 0.5 g of H2

• 1.5 g of H2

• 1.2 g of H2

• 0.3 g of H2

A 2.25 g sample of magnesium nitrate, Mg(NO3)2, contains:

• 42.6 mol

• 0.0268 mol

• 35.45 mol

• 0.0152 mol

How many particles are in 1.80 mol of sulfur dioxide gas?

•  $1.08x10^{24}$  

•  $2.05x10^{22}$  

•  $6.02x10^{23}$  

•  $5.6x10^{21}$  

Water can be formed from the synthesis reaction of hydrogen with oxygen:

2 H2 (g) + O2 (g) → 2 H2O (g)

The complete reaction of 5.12 grams of O2 with excess hydrogen produces how many grams of H2O?

• 7.62

• 5.76

• 3.28

• 4.52

Calcium carbide (CaC2) reacts with water to produce acetylene (C2H2) in the following unbalanced reaction:

CaC2 (s) + H2O (g) → C2H2 (g) + Ca(OH)2 (s)

Production of 13 g of C2H2 requires the consumption of how much H2O?

• 22.7

• 4.2

• 18

• 36

How many moles are in 3.13 g of pyridine $\left(C_5H_5N\right)$ ? 

•  $6.02x10^{23\ }mol$  

•  $2.54x10^{3\ }mol$  

• 27.3 mol

•  $3.96x10^{-2}\ mol$  

Magnesium and nitrogen gas react in a combination reaction to produce magnesium nitride:

3 Mg (s) + N2 (g) → Mg3N2 (s)

In a particular experiment, a 7.40 L sample of N2 reacts completely at STP. The mass of Mg consumed in the reaction is:

• 24.1 g

• 23.5 g

• 38.2 g

• 42.1 g

How many grams are in 1.183 mol of carbon dioxide (CO2) gas?

• 265.0 g

• 3.806 x 1025 g

• 52.06 g

• 37.8 g

How many molecules are in 48.2 g of methane (CH4)?

• $2.90x10^{25\ }molecules$

• $1.81x10^{24\ }molecules$

• $3.00x10^{26\ }molecules$

• $4.53x10^{21\ }molecules$

Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide:

PbCO3 (s) → PbO (s) + CO2 (g)

How many grams of lead (II) oxide will be produced by the decomposition of 2.50 g of lead (II) carbonate?

• 2.25

• 2.75

• 2.36

• 2.09