Amount of substance

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Total cards: 24•Content version: v4•Public deck•Updated: 8/1/2026

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Front (Question)

What is meant by relative atomic mass? Ar

Back (Answer)

• average mass of one atom of an element • divided by 1/12th mass of a C-12 atom

Front (Question)

What is meant by relative molecular mass?

Back (Answer)

• average mass of one molecule • divided by 1/12th mass of a C-12 atom

Front (Question)

Moles/mass/Mr equation

Back (Answer)

Mass (g) = moles x Mr

Front (Question)

Moles/concentration/volume equation

Back (Answer)

moles = conc x volume (dm3)

Front (Question)

State the ideal gas equation

Back (Answer)

PV = nRT P = Pascals V = m3 T = Kelvin R = 8.31 jk-1 mol-1

Front (Question)

Kpa into pascals?

Back (Answer)

multiply by 1000

Front (Question)

m3 to dm3?

Back (Answer)

multiply by 1000

Front (Question)

cm3 to m3?

Back (Answer)

divide by 1 x 10^6

Front (Question)

dm3 to m3?

Back (Answer)

divide by 1000

#10

Front (Question)

dm3 to cm3?

Back (Answer)

multiply by 1000

#11

Front (Question)

m3 to cm3?

Back (Answer)

multiply by 1 x 10^6

#12

Front (Question)

m3 to dm3?

Back (Answer)

multiply by 1000

#13

Front (Question)

What is meant by empirical formula?

Back (Answer)

• Simplest whole number ratio of atoms • of each element in a compound

#14

Front (Question)

What is meant by molecular formula?

Back (Answer)

• Actual number of atoms • of each element in a compound

#15

Front (Question)

% yield formula?

Back (Answer)

amount of specific product formed (actual) / theoretical maximum amount of product that could be formed (theoretical) x 100

#16

Front (Question)

Describe how to make up a standard solution

Back (Answer)

Stage 1: - weigh a sample bottle containing solid - transfer to beaker and reweigh sample bottle - record difference in mass Stage 2: - add distilled water - stir with glass rod - until all solid has dissolved Stage 3: - Transfer to volumetric flask - with washings - make up to 250cm with water - shake/invert

#17

Front (Question)

How to calculate percentage error?

Back (Answer)

% error = error of equipment/amount measured x 100

#18

Front (Question)

Suggest a reason for removing the funnel after it has been used for filling the burette

Back (Answer)

• droplet from funnel could enter burette • affects volume of

#19

Front (Question)

During the titration, the inside of the conical flask is rinsed with distilled water. Suggest why rinsing improves the accuracy of the titre

Back (Answer)

ensures all reactants are able to react

#20

Front (Question)

During a titration, a chemist rinsed the inside of the conical flask with deionised water. The water used for rinsing remained in the conical flask. Explain why the water used for rinsing has no effect on the accuracy of the titre.

Back (Answer)

does not change the number of moles of reactants in the conical flask

#21

Front (Question)

A teacher noticed that a student had not cleared a large air bubble from below the burette tap in preparing the burette for use before starting the titration. This air bubble was ejected during the first titration of the volumetric flask mixture. State the effect that this mistake would have on the value of the first titre.

Back (Answer)

Increase in volume of titre

#22

Front (Question)

Space will fill during titration and titre will be too high. What is the cause of this?

Back (Answer)

not filling burette tap before starting titration

#23

Front (Question)

Ensures all reagents are able to react. What is done in a titration to ensure this?

Back (Answer)

rinsing the walls of the conical flask with deionised water

#24

Front (Question)

Less chance of losing liquid on swirling. What is done in a titration to ensure this?

Back (Answer)

using conical flask instead of a beaker