Chapter C4- Chemical Calculations Flashcards Preview

GCSE AQA Chemistry > Chapter C4- Chemical Calculations > Flashcards

Flashcards in Chapter C4- Chemical Calculations Deck (7)
Loading flashcards...
1
Q

What is relative atomic mass?

What is the relative molecular mass?

What is this also known as?

What is a mole?

What is a mole also referred to as?

What is one mole of a substance?

What is relative molecular mass measured in?

What is relative atomic mass measured in?

What is mass measured in?

What is molar mass also known as?

A

The relative masses of all the atoms in an element

The total atomic masses of all the substances in a compound.

Relative formula masses

6.02 x 10 23 (to power of 23) atoms, ions or molecules.

Avagadro’s number.

Its relative atomic or molecular mass expressed as a figure in grams.

It has no units (not measured in anything)

It has no units (not measured in anything)

Mass is measured in grams (g).

Molecular mass.

2
Q

What is the formula for calculating mass?

What is the formula for calculating moles?

What is the formula for calculating molar mass?

What are the elements on the periodic table expressed in?

Out of the three mentioned, which one is found on the periodic table?

What is this number also the same as on the periodic table and where is this found?

What do the following chemical symbols mean?:

(l)
(s)
(g)
(aq)

A

Mass= moles x molar mass

Moles= mass -:- molar mass

Molar mass= mass -:- moles.

1 mole.

Molecular mass (or molar mass).

Same number as the mass number (where it is found)

Liquid
Solid
Gas
Aquis (dissolved in water).

3
Q

What is percentage yield?

What are the two reasons as to why you can never get 100% yield?

What is the formula to calculate percentage yield?

What is atom economy?

What happens when waste products are made concerning the % yield?

What’s the formula to calculate atom economy?

A

How much you get instead of how much you expected to get.

Processing losses.
Chemical reasons.

Percentage yield= amount of product produced -:- maximum amount of product possibly produced.
X100.

The amount of the desired product made in a reaction compared with the amount of starting reactants usually expressed as a percentage.

You can’t have 100% atom economy.

Relative formula mass of a desired product -:- sum of relative formula masses of reactants
X100%.

4
Q

What does concentration tell you?

What does a more concentrated solution have?

What is concentration described as (measured in)?

What does 1 dm3 equal?

What is the formula for calculating mass (concerning concentrations)?

What’s the formula for calculating volume?

What’s the formula for calculating concentration?

A

How much solute is in a given amount of liquid.

More solute in the same volume than a less concentrated solution.

g/dm3 (cubed).

1000 cm3.

Mass= concentration x volume

Volume= mass -:- concentration

Concentration= mass -:- volume.

5
Q

What is titration?

What is the formula for calculating no of moles in titrations?

What’s the concentration measured in?

How do you calculate concentration?

How do you calculate volume?

What is the end point in a titration?

What are concordant results in titrations?

A

A technique used to determine the concentration of an unknown solution.

No of moles= concentration X volume.

mol/dm3.

Concentration= no of moles -:- volume.

Volume= no of moles -:- concentration.

When the indicator changes colour the solution has been neutralised.

They would all be within 0.1 cm3 of each other.

6
Q

What are two examples of indicators used in titrations?

What is a meniscus?

What does concentration tell us?

What is a soluble base?

What happens when an acid and an alkali react together?

What does this form?

What is titration used to do?

A

Methyl orange and phenolphthalein.

The tightener used in a titration reaction.

The number of moles in 1 dm3 of a solution.

An alkali.

They neutralise each other.

A salt plus water.

Use to measure accurately how much acid and alkali react together completely.

7
Q

What is the volume of 1 mole of any gas?

What is atmosphere a measure of?

What does the no of moles of any substance equal?

What does the no of moles of a gas equal?

In this equation, what does volume equal?

What would happen to the molar gas volume if the temperature was increased?

What would happen to the molar gas volume if the pressure increased?

What is the empirical formula of a compound?

What are the three steps for calculating the empirical formula of a compound (in order)?

A

24 dm3 (24,000 cm3) at room temperature and pressure (rtp) that is 20oc and 1 atmosphere.

Pressure.

Mass (g) -:- Mr (molar mass or molecular mass).

Volume (in dm3) -:- 24 (at RTP).

Volume= mol X 24 (at RTP).

The molar volume of a gas will increase.

The molar volume of a gas will decrease.

The simplest whole number ratio of atoms of each element in the compound.

Find mass of each element, find number of moles, then divide by the smallest to get a whole number which is your answer (in ratio form).