Chemistry Test #1: Chapter 10: Moles, Molar Mass and Volume, Empirical and Molecular Formulas, Percent Composition

What does the measurement of a "ream" equal?

500 sheets of paper

What does the measurement of a "peck" equal?

8 quarts or 2 gallons

What does the measurement of "case" equal?

24

At STP, one mole of any gas occupies how much space?

A volume of 22.4 liters (molar volume)

What are the three rules for determining if a nnumber is significant or not?

All non-zero numbers are significant, zero is significant when it is trapped between two other significant figures or when it is trailing to the right of a decimal.

The number of representative particles in the mole is called this, named after an Italian scientist.

Avogadro's Number

Equal volumes of gases at the same temperature and pressure contain equal numbers of particles.

Avogadro's hypothesis

What should you base your number of Sig-figs off of when calculating measurements?

Base it off of your measurements and not indefinite numbers like molar mass or Avogadro's number.

What are three ways in which people measure things?

Count, Mass, and Volume

What is the density of moles equation?

Density (g/L)= Molar mass/Molar volume

The basic ratio that gives the lowest whole number ratio of the atoms of the elements in a compound.

Empirical Formula

How do you calculate the molar mass of a compound?

Find the molar mass (atomic mass) of each element in grams and then add them together.

What is the volume of a gas equation?

Gas=moles of gas X 22.4L/1mole

The mass of a mole of any element.

Molar mass

The name of the number representing 6.02 X 10^23 particles of a substance in the SI unit of measurement.

Mole

When rounding masses on the periodic table, you should round the masses to what?

One decimal place

The relative amounts of the elements in a compound are expressed as this term.

Percent Composition

What are the two examples from which you can find percent composition from?

Percent Composition from the Chemical Formula and Percent composition from Mass Data.

What are the three relationships of Moles?

Related to the # of things, masses, or volumes of gases

The species present in a substance; usually atoms, molecules, or formula units.

Representative particles

Temperature of 0 degrees Celsius and a pressure of 101.3 or 1 atmosphere.

Standard Temperature and Pressure

What is the rule for determining sig-figs from addition and subtraction?

The number of decimals in your answer must equal the number you added or subtracted with the least amount of decimals.

What does the measurement of a "gross" equal?

144 or 12 dozen

What is the rule for determining sig-figs from multiplication and division?

The number of sig-figs in your answer equals the amount of sig-figs of the number you multiplied with the least amount of sig figs.

What can the molecular formula of compound be?

The same as its empirical formula or a whole-number multiple of it's empirical formula.