# Formulae, equations and Amounts of substances Flashcards

Define the mole

The amount of substance in grams that has the same number of particles as there are atoms in 12 grams of Carbon-12

Define relative atomic mass

The average mass of one atom compared to one-twelfth of the mass of an atom of carbon-12

Define Molar Mass

The mass in grams of one mole of a substance given in the unit of g/mol

what is the formula for moles

Mass/Mr

What is the formula for concentration

moles/volume or mass/volume

What is the formula for the volume of a gas at room temp and pressure

moles x 24

what is the formula of a new diluted solution?

original conc x original volume/new diluted volume

What is the difference between a random error and a systematic error?

random error: caused by unpredictable changes in conditions or by a difference in recording that is difficult to get right.

Systematic error: caused by the apparatus- causes reading to be too high or low.

State the difference between a mistake and an error

error: the difference between an experimental and true or correct value.

Mistake: something that even a skilled operator finds difficult to avoid, but can be avoided through taking different measures.

What is the formula for percentage error in an apparatus?

uncertainty/reading x 100

How can we reduce errors?

- use more precise equipment
- measure larger volumes of liquid with the same accuracy.