Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemistry - GCSE > Chemistry: Calculations > Flashcards

Chemistry: Calculations Flashcards

(51 cards)

Start Studying
1
Q

What is relative atomic mass of magnesium?
What is relative atomic mass of oxygen?
What is relative molecular mass of Mgo? (Magnesium oxide

A

Mg - 24
O - 16
Mgo : 40 (16+24)

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

What symbol is relative atomic mass represented by?

A

(A(littleR))

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

What symbol is relative formula mass represented by?

A

(M(littleR))

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

What is relative atomic mass?

A

The mean mass of an atom of an element compared to carbon - 12 (basically just the mass number)

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

What is relative formula mass?

A

The sum of the relative atomic masses of all the atoms or ions in its formula

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

What is molecular formula?

A

Molecular formula represents the actual number of atoms of each element in one molecule

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

What is empirical formula?

A

The simplest ratio of different atoms in a compound

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

What do you need to know to work out empirical formula?

A

You need to know the mass (g) of each element and Relative atomic mass

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

What is number of moles equal to?

A

Mass

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

Ethene has a molecular formula of C(little2)H(little4)

What is the empirical formula?

A

Find highest common factor of two little numbers and divide both by this value
HCF of 2 and 4 is 2
Empirical formula = CH(little2)

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

Calculate the M(littleR) of Carbon dioxide

A

CO(little2)
=A(littleR) (C) + (2xA(littleR) (O))
=12+(2x16)

M(littleR) of CO(little2) = 44

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

Calculate the M(littleR) for Ca(NO(little3)(little2)

A

=A(littleR) (Ca) +2 (A(littleR)(N)+(3xA(littleR)(O)))

=40+2(14+(3x16))

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

What is concentration?

A

The amount of solute dissolved in a stated volume of solution

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

What are the units for concentration?

A

(gdm^-3)

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

What is the equation for concentration

A

Concentration = mass of solute / volume of solution

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

What are the SI units for mass of solute?

A

Grams (g

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are SI units for volume of solution?

A

Decimetre (dm^3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the rule or what happens to mass during a chemical reaction.

A

Mass is not created or destroyed during the course of a chemical reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the law of conservation of a mass?

A

The mass of reactants must equal the mass of the products in a chemical reaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What do we do during a chemical reaction?

A

We rearrange atoms to produce new materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

During a chemical reaction, the mass of the reaction doesn’t change. What is this called?

Study These Flashcards
A

A closed system

22
Q

During a chemical reaction, the mass of the products appears to decrease. What is this called? Why does this happen?

Study These Flashcards
A

Non-enclosed system, gas escaping

23
Q

What happens in a closed system?

Study These Flashcards
A

Mass doesn’t change because no gas is being produced/escaping

24
Q

What happens in a open system?

Study These Flashcards
A

Mass decreases as a gas is being given off

25
2Mg + O(little2) > 2Mgo | I react 10g of magnesium with 5g of oxygen. What mass of magnesium would I form?
10g +5g =15g
26
I react 15g of magnesium and form 25g of magnesium oxide. What mass of oxygen reacted?
15g +0(little2) =25g | O(little2) =10g
27
In a formula, what do the little numbers do? E.g.: O(little2) = ?
Affect the element behind it | E.g.: O(little2) = o x 2
28
In a formula, what do the big numbers do? | E.g.: 2H(little2)O =?
E.g.: 2H(little2)O = 4xH, 2xO | Affect the whole compound
29
In a formula, what do the small numbers outside brackets do? E.g.: (CO(little3))(little3) =?
E.g.: (CO(little3))(little3) =3xc, 9xO | Multiply everything inside the bracket by that number
30
What three things are balance in a chemical equation?
Atoms, mass, charge
31
What is the rule for little numbers in a formula?
You cannot add or change little numbers, only big
32
What is the easy way of saying what the relative formula mass of a compound is?
The relative atomic masses of all elements in compound added together
33
What mass of magnesium oxide is produced when 60g of magnesium is burned in air?
``` 1: get your equation 2Mg + O(little2) > 2MgO 2: get relative atomic masses of: Mg - 24 O(little2) - 16 MgO - 40 2MgO - 80 2Mg=2x24=48 2MgO=2x(24+16)=80 3:Learn and apply the following points: 48g of Mg makes 80g of MgO 1g of Mg makes 80/48 = 1.66g of MgO 60g of Mg makes 1.66 x 60= 100g of MgO ```
34
What is a mole?
A way of counting
35
Give Avogadro's number
6.02 x 10^23
36
What does 6.02 x 10^23 represent?
1 mole of substance
37
What is the mass of 1 mole of a substance?
The relative atomic mass or relative formulaic mass in grams
38
If the relative atomic mass of magnesium is 24, what is the mass of 1 mol of magnesium, and how many atoms does this contain?
1 mol of magnesium has a mass of 24g containing 6.02x10^28 atoms
39
What is the equation to calculate the number of moles in any substance?
Number of moles of substance= mass of substance (g) / Ar or Mr (use periodic table to find this)
40
What is the mass of 1 mol of carbon atoms?
1 x 12 = 1
41
What is 0.1mol of silver dioxide molecules?
S= 32 O(little 2) =16 x 2 = 32 32+32 = 64 0.1 mol: 6.4
42
What do moles tend to measure?
Particles (atoms or molecules of ions)
43
How many molecules are O(little2)?
1 molecule
44
How many molecules is 2MgO?
2 molecules
45
What type of equation is 2Mg+O(little2) > 2MgO? What does it tell us in relation to moles?
A balanced chemical equation. It shows us that 2 moles of magnesium reacts with 1 mole of oxygen
46
In chemical reactions, what is added in excess? What happens to it?
One of the reactants is added in excess and isn't completely used up in the reaction
47
What is the amount of product in a chemical reaction controlled by? What is this called?
The reactant that is not in excess: the limiting reactant
48
What is the ratio of the moles of each substance called?
The stoichiometry of the reaction.
49
Calculate the number of molecules in 90g of water
Water = H(little2)O 1:calculate relative formula mass of water Mr(H(little2)O): 1+1+16=18 2:calculate the number of moles in 90g of water Mole = 90/18 = 5 moles of water 3:multiply the number of moles by Avogadro's number 5x6.02x10^23=3.01x10^24 ^ leave answer in standard form
50
How many atoms/particles/molecules does 1 mole have?
6.02x10^23
51
What are the 6 elements that travel in pairs?
I(little2), Cl(little2), Br(little2), O(little2), N(little2), H(little2) Iodine, chlorine, bromine, Oxygen, Nitrogen, Hydrogen

Chemistry - GCSE (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions