Chemical Calculations

Mole ratios from balanced equations may be used to solve problems with other units such as numbers of

representative particles

Mole ratios from balanced equations may be used to solve problems with other units such as numbers of representative particles and____ of gases at STP

volumes

The ____from the balanced equation are used to write conversion factors called mole ratios.

coefficients

The coefficients from the balanced equation are used

to write conversion factors called

mole ratios

These conversion factors are used to calculate the numbers of moles of ____ from a given number of moles of reactants.

products

These conversion factors are used to calculate the numbers of moles of products from a given number of moles of

reactants

In mass-mass calculations, the molar mass is used to convert mass to

moles

In mass-mass calculations, the molar mass is used to convert mass to moles.

AT

The mole ratio 2 mol HF/1 mol SnF2 can be used to determine the mass of SnF2 produced according to the equation: Sn(s) + 2HF(g) ----> SnF2(s) + H2(g)

NT

In a volume-volume problem, the 22.4 L/mol factors always cancel out.

AT

In stoichiometric problems, volume is expressed in terms of liters.

NT

For a mass-mole problem, the first conversion from mass to moles is skipped

NT

For a mass-mass problem, the first conversion is from moles to mass

NT

Because mole ratios from balanced equations are exact numbers, they do not enter into the determination of significant figures.

AT

How many liters of carbon monoxide (at STP) are needed to react with 4.8 g of oxygen gas to produce carbon dioxide?

6.7 L

What mass of ammonia, NH3, is necessary to react with 2.1 x 1024 molecules of oxygen in the following reaction? 4NH3(g) + 7O2(g) -----> 6H2O(g) + 4NO2(g)

33.9 grams

Is it essential to have a balanced equation prior performing calculations involving amounts of reactants and products?

True

If you know the number of moles of one substance in a reaction, you need more information than the balanced chemical equation to determine the number of moles of all the other substances in the reaction

False

The coefficients from a balanced chemical equation are used to write conversion factors called

mole ratios

2K(s) + Cl2(g) ---> 2KCl(s)

Laboratory balances are used to measure moles of substances directly

False

The amount of a substance is usually determined by measuring its mass in

grams

If a sample is measured in grams, molar mass can be used to convert the mass to moles.

True

Stoichiometric calculations can be expanded to include any unit of measurement that is related to the mole.

True

In any problem relating to stoichiometric calculations, the given quantity is first converted to

moles