When magnesium metal and an aqueous solution of hydrochloric acid combine, they produce an aqueous solution of magnesium chloride and hydrogen gas. Using the equation, Mg (s) + 2HCl (aq) Imported Asset MgCl2 (aq) + H2 (g), if 72.9 g of Mg and 146.0 g of HCl are allowed to react, identify the limiting reagent.
Mg
HCl
MgCl2
H2
QUESTION 8
When magnesium metal and an aqueous solution of hydrochloric acid combine, they produce an aqueous solution of magnesium chloride and hydrogen gas. Using the equation, Mg (s) + 2HCl (aq) Imported Asset MgCl2 (aq) + H2 (g), if 48.6 g of Mg and 150.0 g of HCl are allowed to react, identify the limiting reagent.
Mg
HCl
MgCl2
H2
QUESTION 9
The number of moles of the reagent in excess can be used to calculate the moles of the products of the reaction.
TRUE
FALSE
QUESTION 10
Ammonia gas is formed from nitrogen gas and hydrogen gas according to the following equation: N2 (g) + 3H2 (g) Imported Asset 2NH3 (g). If 112 grams of nitrogen gas is allowed to react with an excess of hydrogen gas to produce 120 grams of ammonia, what is the percent yield of this reaction?
44.1%
66.2%
88.3%
96.4%
QUESTION 11
Ammonia gas is formed from nitrogen gas and hydrogen gas, according to the following equation: N2 (g) + 3H2 (g) Imported Asset 2NH3 (g). If 84.0 g of nitrogen gas is allowed to react with an excess of hydrogen gas to produce 85.0 g of ammonia, what is the percent yield of this reaction?
42.2%
65.0%
70.3%
83.3%
QUESTION 12
Ammonia gas is formed from nitrogen gas and hydrogen gas, according to the following equation, N2 (g) + 3H2 (g) Imported Asset 2NH3 (g). If 140 grams of nitrogen gas is allowed to react with an excess of hydrogen gas to produce 155 grams of ammonia, what is the percent yield of this reaction?
45.5%
67.0%
82.4%
91.2%
3 points Save Answer
QUESTION 13
The actual yield is usually less than the predicted (theoretical) yield.
TRUE
FALSE
2 points Save Answer
QUESTION 14
The theoretical yield for a chemical reaction can not be calculated until the reaction is completed.
TRUE
FALSE
Not only do you not get it, you apparently didn't even read how to do the first one.
To identify the limiting reagent in a chemical reaction, you need to compare the amounts of reactants and their stoichiometric ratios given by the balanced chemical equation.
In the first question, you have 72.9 g of Mg and 146.0 g of HCl.
To determine the limiting reagent, begin by converting the masses of both reactants to moles.
Molar mass of Mg = 24.31 g/mol
Molar mass of HCl = 36.46 g/mol
Moles of Mg = mass / molar mass = 72.9 g / 24.31 g/mol = 2.999 moles (approx.)
Moles of HCl = mass / molar mass = 146.0 g / 36.46 g/mol = 4.003 moles (approx.)
From the balanced equation, the stoichiometric ratio between Mg and HCl is 1:2. This means that 1 mole of Mg reacts with 2 moles of HCl.
Comparing the mole ratios with the actual moles calculated:
Mg : HCl = 2.999 : 4.003 (approx.)
Since the ratio is close to 1:2, it indicates that there is an excess of HCl, making it the excess reagent. Therefore, Mg is the limiting reagent.
Similarly, you can follow the same procedure for the second question to identify the limiting reagent.
In questions 8 and 9, there is no need to identify the limiting reagent. They are asking whether the given statement is true or false.
In question 10, to calculate the percent yield, you need to compare the actual yield with the theoretical yield. The theoretical yield is the maximum amount of product that can be obtained from the given amounts of reactants, based on the stoichiometry.
To calculate the theoretical yield, you need to determine the limiting reagent and find the amount of product that can be formed from it. From the balanced equation, the stoichiometric ratio between N2 and NH3 is 1:2.
Molar mass of N2 = 28.02 g/mol
Molar mass of NH3 = 17.03 g/mol
Moles of N2 = mass / molar mass = 112 g / 28.02 g/mol = 3.996 moles (approx.)
Since the stoichiometric ratio is 1:2, the theoretical yield of NH3 would be twice the moles of N2:
Theoretical yield of NH3 = 2 * moles of N2 = 2 * 3.996 moles (approx.)
To calculate the percent yield, you need the actual yield. In this case, it is given as 120 grams.
Percent yield = (actual yield / theoretical yield) * 100
Percent yield = (120 g / (2 * 3.996)) * 100
Calculate the value to get the correct answer.
Similarly, you can follow the same procedure for questions 11 and 12 to calculate the percent yield.
In questions 13 and 14, they are asking whether the given statements are true or false.