SACE Stage 1 Chemistry - 2.3 Quantities (Part 3)

What is stoichiometry?

• The study of chemical reactions involving heat transfer.

• The quantitative relationship between reactants and products in a balanced chemical equation.

• The process of balancing chemical equations.

• The study of reaction rates and mechanisms.

If a pancake recipe requires 2 eggs to make 5 pancakes, how many eggs are needed to make 20 pancakes?

• 4 eggs

• 6 eggs

• 8 eggs

• 10 eggs

What don't you do when calculating the molar mass of a substance?

• Consider the different elements in the substance

• Consider the subscripts in the chemical formula of a substance

• Consider the relative atomic masses of the different elements in the substance

• Consider the coefficient in front of the chemical formula

What is the number of moles of aluminum (Al) if 1.05 g of aluminum reacts? (Molar mass of Al = 26.98 g/mol)

• 0.0389 mol

• 0.0390 mol

• 28.329 mol

• 25.93 mol

How many moles of aluminum (Al) is needed to form 3.605 g of aluminum oxide (Al2O3)? (Molar mass of Al = 26.98 g/mol, Molar mass of Al2O3 = 101.96 g/mol, Balanced equation: 4Al + 3O2 -> 2Al2O3)

• 0.0177 mol

• 0.0707 mol

• 0.354 mol

• 0.133 mol

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