Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry > 2.3 Amount of Substance > Flashcards

2.3 Amount of Substance Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

What is a mole ?

A

Amount of any substance certaining as many particles as there are carbon atoms in 12g of carbon-12.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is Avogadro’s constant ?

A

6.02x10^23
It is the number of atoms per mole of carbon-12.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is molar mass ?

A

It is the mass per mole of a substance (g/mol-1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How to work out number of moles?

A

Mass (g) / molar mass (g/molar-1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How to work out number of particles ?

A

Number of moles x Avogadro’s constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does 1 mole of gas at room temperature and pressure obtain?

A

24 dm^3 (24dm^3 = 24000cm^3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Molecular Formulae

A

Number of atoms of each element in a molecule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Empirical Formula

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How to calculate empirical formula ?

A

1) Mass/molar mass = no of moles.
2) Divide by smallest number.
3) Make a whole number ratio.
4) Create formula.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Relative molecular mass

A

Compares mass of molecule with mass of an atom of carbon-12.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Relative formula mass

A

Compares mass of formula unit to that of an atom of carbon-12.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why are many coloured salts hydrated ?

A

This is because water is a part of their crystalline structure. This water is known as the water of crystallisation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens when copper (II) sulphate salt is heated ?

A

Water bonds within the crystal are broken and water is driven off leaving behind the white anhydrous powder.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Equation for copper (II) sulphate reaction

A

CuSO4.5H2O = CuSO4 + 5H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens to heated CuSO4 when no water is returned ?

A

Crystalline structure is lost and white anhydrous powder remains.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Equation for volume

A

Volume = number of moles x 24 dm^3

17
Q

What is the ideal gas equation ?

A

pV = nRT

P= pressure 1atm = 101000pa
V = volume 1dm = 1000cm
N = no of moles (mol)
R = molar gas constant =8.314 mol-1
T= temp(•c) +273 = kelvin

18
Q

What is concentration ?

A

Concentration is the number of moles of a solute dissolved in 1dm^3 of a solution.

19
Q

What is the equation for finding concentration?

A

concentration= Mass or Moles / Volume

20
Q

What is a standard solution?

A

A solution with a known concentration.

21
Q

What is the molar gas volume ?

A

Volume per mole of gas molecules at standard temperature and pressure.

22
Q

Equation for Molar gas volume

A

number of moles= volume/molar gas volume

23
Q

What is the stoichiometry ?

A

The ratio of number, from balanced equation, of the amount of moles of each substance.

24
Q

What is percentage yield ?

A

% of a desired product.

25
Q

What is theoretical yield ?

A

Maximum possible amount of product that can be produced.

26
Q

What is actual yield ?

A

How much product is actually produced from a reaction. Usually lower than theoretical yield.

27
Q

Equation for percentage yield

A

%=actual yield/theoretical yield x 100

28
Q

What are excess and limiting reagents ?

A

Limiting reagent is reactant not in excess that gets used up first in reaction.

29
Q

How to find limiting reagent ?

A

1) Find moles of each reactant in equation.
2)Find smallest amount of moles.
3)Use mole number to find amount of moles for other products based on stoichiometry.

30
Q

What is atom economy ?

A

Atom economy is a measure of how well the atoms have been utilised.

31
Q

Equation for atom economy

A

sum of desired amount/ sum of molar mass of all x 100

32
Q

Why are high atom economies good ?

A

Means reaction produced large quantities of desired product, with little waste products being made. More sustainable as it makes most use out of natural resources used.

Chemistry (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions