Chemical Reactions and Reaction Stoichiometry

How many grams of calcium hydride are needed to form 4.700 g of hydrogen gas?

49.07 g

What is the mass percentage of each element in the compound Al2O3?

% Al,% O = 52.9,47.1 %

How many molecules (not moles) of NH3 are produced from 5.14×10−4 g of H2?

1.02 x 10^20 molecules

Phosphoric acid reacts with magnesium hydroxide to produce magnesium phosphate and water via the following reaction: ?H3PO4+?Mg(OH)2→?Mg3(PO4)2+?H2O Balance the equation and enter the coefficients.

2,3,1,6

How many grams of H2 are needed to produce 12.40 g of NH3?

2.202 g H2

How many sulfur atoms are in 0.45 mol BaSO4?

2.7 x 10^23

A compound whose empirical formula is XF3 consists of 65 % F by mass. What is the atomic mass of X?

31 g/mol

1.13 g H2 is allowed to react with 9.89 g N2, producing 2.79 g NH3. What is the theoretical yield in grams for this reaction under the given conditions?

6.37 g

A certain ionic compound is made entirely of aluminum and oxygen. What is the formula for this compound?

Al2O3

Write a balanced chemical equation for the reaction that occurs when heptane, C7H16(l) , burns in air.

C7H16(l)+11O2(g)→7CO2(g)+8H2O(g)

Write a balanced chemical equation for the reaction that occurs when copper (II) hydroxide decomposes into copper (II) oxide and water when heated.

Cu(OH)2(s)→CuO(s)+H2)(l)

The compound dioxane, which is used as a solvent in various industrial processes, is composed of C, H, and O atoms. Combustion of a 2.203-g sample of this compound produces 4.401 g CO2 and 1.802 g H2O. A separate experiment shows that it has a molar mass of 88.1 g/mol. Which of the following is the correct molecular formula for dioxane?

C4H8O2

What is the chemical formula for quartz?

SiO2

How many sulfur atoms are in 1.10 mol of aluminum sulfide?

1.99x 10^24

How many moles of NH3 can be produced from 19.5 mol of H2 and excess N2?

13.0 mol NH3

How many grams of NH3 can be produced from 4.02 mol of N2 and excess H2?

137 g NH3

When 24 mol of methanol and 15 mol of oxygen combine in the combustion reaction, 2 CH3OH(g) + 3 O2(g) → 2 CO2(g) + 4 H2O(g) what is the excess reactant and how many moles of it remain at the end of the reaction?

14 mol CH3OH(g)

Write a balanced chemical equation for the reaction that occurs when the gasoline additive methyl tert-butyl ether, C5H12O(l), burns in air.

2C5H12O(l)+15O2(g)→10CO2(g)+12H2O(g)

Write a balanced chemical equation for the reaction that occurs when calcium metal undergoes a combination reaction with O2(g).

2Ca(s)+O2(g)→2CaO(s)

Which of the following is the correct formula weight for calcium phosphate?

310.2 amu

The unbalanced equation for the reaction between methane and bromine is: __CH4(g) + __Br2(l) → __CBr4(s) + __HBr(g) Once this equation is balanced what is the value of the coefficient in front of bromine Br2?

4

How many oxygen atoms are in 2.10 g of quartz?

4.21 x 10^22

1.13 g H2 is allowed to react with 9.89 g N2, producing 2.79 g NH3. What is the percent yield for this reaction under the given conditions?

43.8%

You carefully weigh out 20.00 g of CaCO3 powder and add it to 81.00 g of HCl solution. You notice bubbles as a reaction takes place. You then weigh the resulting solution and find that it has a mass of 92.80 g . The relevant equation is CaCO3(s)+2HCl(aq)→H2O(l)+CO2(g)+CaCl2(aq) Assuming no other reactions take place, what mass of CO2 was produced in this reaction?

8.20 g

Calcium hydride reacts with water to form calcium hydroxide (aqueous) and hydrogen gas. Write a balanced chemical equation for the reaction.

CaH2(s)+2H2O(l)→Ca(OH)2(aq)+2H2(g)