Reacting masses and volumes

Reacting masses and volumes

By Angela Toh

Multiple Choice

What name is given to the number of atoms in a mole of an element?

• Planck's constant

• Avogadro's constant

• Newtonian constant

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Compute for the molar mass of H₂O. (include units in your answer)

Multiple Select

A mole can be represented by the (SELECT ALL CORRECT ANSWERS)

• 22.4 liters of a gas at STP

• The amount of molecules or atoms in a substance

• Molar mass found on the periodic table of elements

• The amount of fission or fusion decay over time

Multiple Choice

What is the definition for Avogadro's number?

• number of grams per one mole of a substance
• whole number ratio that is a multiple of a chemical formula
• simplest, whole number ratio of a chemical formula
• 6.02 x 10²³ particles per one mole of a substance

Multiple Choice

Mole Ratios used for conversions are derived from:

• the molar mass of the reactants in the balanced chemical equation

• the coefficients of the balanced chemical equation

• the subscripts of the products in the balanced chemical equation

• the group number of each element in the balanced chemical equation

Multiple Choice

BALANCED chemical equations tell you the relative amounts or the ratios of reactants and products.  Use the following BALANCED chemical equation to determine the ratio: $$2HgO\ \rightarrow\ 2Hg\ +\ O_2$$    What is the ratio of HgO to Hg

• 2:2

• 1:1

• 2:1

• 1:2

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Calculate the SO₂ : CO₂ mole ratio in the mixture obtained after combustion.

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(a) Calculate the molar mass of copper(II) sulfate-5-water.

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(b) Calculate the amount (in mol) of copper(II) sulfate-5-water in a 10.0 g sample.

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(c) Calculate the mass of copper(II) oxide needed to make this 10.0 g sample.

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(a) Calculate the amount (in mol) of barium sulfate formed.

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(b) Determine the amount (in mol) of the alkali metal sulfate present.

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(c) Determine the molar mass of the alkali metal sulfate and state its units.            

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(d) Deduce the identity of the alkali metal, showing your workings.       

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(e) Write an equation for the precipitation reaction, including state symbols.