1. what mass of h2o will be produced if 9.5 g of h2 reacts with 1.2 g of o2? __ h2 + __ o2 --> __ h2o 2. if 1.85 g of mg(oh)2 reacts with 3.71 g of hcl, how much mgcl2 is produced? what is the limiting reactant? __ mg(oh)2 + __ hcl --> __ mgcl2 + __ h2o 3. what mass of potassium hydroxide is formed when 8.2 g of potassium oxide is added to 1.3 g of water? __ k2o + __ h2o --> __ koh 4. what mass of aluminum chloride could be made from 8.1 g of aluminum and 4.2 l of chlorine at stp? __ al + __ cl2 --> __ alcl3 i know this is a lot of questions but and show your work. you.

1) The answer is: mass of water is 1.35 grams.

Balanced chemical reaction: 2H₂ + O₂ → 2H₂O.

m(O₂) = 1.2 g; mass of oxygen.

M(O₂) = 2 · 16 g/mol.

M = 32 g/mol, molar mass of oxygen.

n(O₂) = m(O₂) ÷ M(O₂).

n(O₂) = 1.2 g ÷ 32 g/mol.

n(O₂) = 0.0375 mol; amount of oxygen, limiting reactant.

m(H₂) = 9.5 g; mass of hydrogen.

M(H₂) = 2 g/mol, molar mass of hydrogen.

n(H₂) = m(H₂) ÷ M(H₂).

n(H₂) = 9.5 g ÷ 2 g/mol.

n(H₂) = 4.5 mol; amount of hydrogen.

From chemical reaction: n(O₂) : n(H₂O) = 1 : 2.

n(H₂O) = 0.0375 mol · 2.

n(H₂O) = 0.075 mol; amount of water.

m(H₂O) = n(H₂O) · M(H₂O).

m(H₂O) = 0.075 mol · 18 g/mol.

m(H₂O) = 1.35 g; mass of water.

2) The answer is: 3.05 grams of MgCl₂ is produced, the limiting reactant is Mg(OH)₂.

Balanced chemical reaction: 2HCl + Mg(OH)₂ → MgCl₂ + 2H₂O.

m(Mg(OH)₂) = 1.85 g; mass of magnesium hydroxide

n(Mg(OH)₂) = m(Mg(OH)₂) ÷ M(Mg(OH)₂).

n(Mg(OH)₂) = 1.85 g ÷ 58.32 g/mol.

n(Mg(OH)₂) = 0.032 mol; limiting reactant.

m(HCl) = 3.71 g; mass of hydrochloric acid.

n(HCl) = 3.71 g ÷ 36.46 g/mol.

n(HCl) = 0.102 mol; amount of hydrochloric acid.

From chemical reaction: n(Mg(OH)₂) : n(MgCl₂) = 1 : 1.

n(MgCl₂) =0.032 mol; amount of magnesium chloride.

m(MgCl₂) = n(MgCl₂) · M(MgCl₂).

m(MgCl₂) = 0.032 mol · 95.21 g/mol.

m(MgCl₂) = 3.05 g; mass of magnesium chloride.

3) The answer is: mass of potassium hydroxide is 8.1 grams.

Balanced chemical reaction: K₂O + H₂O → 2KOH.

m(K₂O) = 8.2 g; mass of potassium oxide.

n(K₂O) = m(K₂O) ÷ M(K₂O).

n(K₂O) = 8.2 g ÷ 94.2 g/mol.

n(K₂O) = 0.087 mol; amount of potassium oxide.

m(H₂O) = 1.3 g; mass of water.

n(H₂O) = 1.3 g ÷ 18 g/mol.

n(H₂O) = 0.072 mol; limiting reactant.

From chemical reaction: n(H₂O) : n(KOH) = 1 : 2.

n(KOH) = 2 · 0.072 mol.

n(KOH) = 0.144 mol.

m(KOH) = 0.144 mol · 56.1 g/mol.

m(KOH) = 8.1 g; mass of potassium hydroxide.

4) The answer is: mass of aluminum chloride is 16.66 grams.

Balanced chemical reaction: 2Al + 3Cl₂ → 2AlCl₃.

m(Al) = 8.1 g; mass of aluminium.

n(Al) = m(Al) ÷ M(Al).

n(Al) = 8.1 g ÷ 27 g/mol.

n(Al) = 0.3 mol.

V(Cl₂) = 4.2 L; volume of chlorine.

n(Cl₂) = 4.2 L ÷ 22.4 L/mol.

n(Cl₂) = 0.1875 mol; limiting reactant.

From chemical reaction: n(Cl₂) : n(AlCl₃) = 3 : 2.

n(AlCl₃) = 2 · 0.1875 mol ÷ 3.

n(AlCl₃) = 0.125 mol; amount of aluminium chloride.

m(AlCl₃) = 0.125 mol · 133.34 g/mol.

m(AlCl₃) = 16.66 g; mass of aluminium chloride.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.

c. 4.54 x 10–12 j happens to be correct