140k views
3 votes
Conservation of Mass In chemical reactions, mass is neither gained nor lost. The total mass of all the reactants equals the total mass of all the products. Atoms are just rearranged into different compounds. Using this idea, solve the following problems. 1. 2KCIO3 2KCI+ 30₂ If 500 g of KCIO, decomposes and produces 303 g of KCI, how many grams of O₂ are produced? 2. N₂ + 3H₂ 2NH3 How many grams of H₂ are needed to react with 100 g of N₂ to produce 121 g of NH₂? 3. 4Fe +30₂ 2Fe₂O3 How many grams of oxygen are needed to react with 350 g of iron to produce 500 g of Fe₂O3? 4. CH₂ + 20₂2 CO₂ + 2H₂O 16 g of CH₂ react with 64 g of O₂, producing 44 g of CO₂ How many grams of water are produced? 5. CaCO3 Cao + CO, How much CO, is produced from the decomposition of 200 g of CaCO, if 112 g of CaO are produced?​

User NicoTek
by
7.5k points

1 Answer

6 votes

Answer:

1. The balanced equation is 2KCIO3 → 2KCI + 3O2. According to the law of conservation of mass, the mass of the reactants must equal the mass of the products. Therefore, the mass of oxygen produced is:

Mass of oxygen = Mass of KCIO3 - Mass of KCI

Mass of oxygen = 500 g - 303 g

Mass of oxygen = 197 g

Therefore, 197 g of O2 are produced.

2. The balanced equation is N2 + 3H2 → 2NH3. We need to find out how much H2 is needed to react with 100 g of N2 to produce 121 g of NH3. First, we need to calculate the number of moles of N2 and NH3:

Moles of N2 = Mass of N2 / Molar mass of N2

Moles of N2 = 100 g / 28 g/mol

Moles of N2 = 3.57 mol

Moles of NH3 = Mass of NH3 / Molar mass of NH3

Moles of NH3 = 121 g / 17 g/mol

Moles of NH3 = 7.12 mol

According to the balanced equation, 1 mole of N2 reacts with 3 moles of H2 to produce 2 moles of NH3. Therefore, the number of moles of H2 needed is:

Moles of H2 = Moles of N2 x (3/1)

Moles of H2 = 3.57 mol x 3

Moles of H2 = 10.71 mol

Finally, we can calculate the mass of H2 needed:

Mass of H2 = Moles of H2 x Molar mass of H2

Mass of H2 = 10.71 mol x 2 g/mol

Mass of H2 = 21.42 g

Therefore, 21.42 g of H2 are needed.

3. The balanced equation is 4Fe + 3O2 → 2Fe2O3. We need to find out how much oxygen is needed to react with 350 g of Fe to produce 500 g of Fe2O3. First, we need to calculate the number of moles of Fe and Fe2O3:

Moles of Fe = Mass of Fe / Molar mass of Fe

Moles of Fe = 350 g / 55.85 g/mol

Moles of Fe = 6.26 mol

Moles of Fe2O3 = Mass of Fe2O3 / Molar mass of Fe2O3

Moles of Fe2O3 = 500 g / 159.69 g/mol

Moles of Fe2O3 = 3.13 mol

According to the balanced equation, 4 moles of Fe react with 3 moles of O2 to produce 2 moles of Fe2O3. Therefore, the number of moles of O2 needed is:

Moles of O2 = Moles of Fe x (3/4)

Moles of O2 = 6.26 mol x (3/4)

Moles of O2 = 4.69 mol

Finally, we can calculate the mass of O2 needed:

Mass of O2 = Moles of O2 x Molar mass of O2

Mass of O2 = 4.69 mol x 32 g/mol

Mass of O2 = 150.08 g

Therefore, 150.08 g of O2 are needed.

4. The balanced equation is CH2 + 2O2 → CO2 + 2H2O. We know that 16 g of CH2 reacts with 64 g of O2 to produce 44 g of CO2. We need to find out how much water is produced. First, we need to calculate the number of moles of CH2 and CO2:

Moles of CH2 = Mass of CH2 / Molar mass of CH2

Moles of CH2 = 16 g / 14 g/mol

Moles of CH2 = 1.14 mol

Moles of CO2 = Mass of CO2 / Molar mass of CO2

Moles of CO2 = 44 g / 44 g/mol

Moles of CO2 = 1 mol

According to the balanced equation, 1 mole of CH2 reacts with 2 moles of O2 to produce 2 moles of H2O. Therefore, the number of moles of H2O produced is:

Moles of H2O = Moles of CH2 x (2/1)

Moles of H2O = 1.14 mol x 2

Moles of H2O = 2.28 mol

Finally, we can calculate the mass of H2O produced:

Mass of H2O = Moles of H2O x Molar mass of H2O

Mass of H2O = 2.28 mol x 18 g/mol

Mass of H2O = 41.04 g

Therefore, 41.04 g of H2O are produced.

5. The balanced equation is CaCO3 → CaO + CO2. We need to find out how much CO2 is produced from the decomposition of 200 g of CaCO3 if 112 g of CaO are produced. First, we need to calculate the number of moles of CaCO3 and CaO:

Moles of CaCO3 = Mass of CaCO3 / Molar mass of CaCO3

Moles of CaCO3 = 200 g / 100.09 g/mol

Moles of CaCO3 = 1.999 mol

Moles of CaO = Mass of CaO / Molar mass of CaO

Moles of CaO = 112 g / 56.08 g/mol

Moles of CaO = 1.999 mol

According to the balanced equation, 1 mole of CaCO3 produces 1 mole of CaO and 1 mole of CO2. Therefore, the number of moles of CO2 produced is:

Moles of CO2 = Moles of CaCO3 x (1/1)

Moles of CO2 = 1.999 mol

Finally, we can calculate the mass of CO2 produced:

Mass of CO2 = Moles of CO2 x Molar mass of CO2

Mass of CO2 = 1.999 mol x 44 g/mol

Mass of CO2 = 87.96 g

Therefore, 87.96 g of CO2 are produced.

User Mike Trader
by
6.6k points