Topic 1: Stoichiometry Flashcards

1
Q

What is a homogenous mixture

A

All substances in mixture in the same phase (NOT STATE) essentially everything is mixed so well you can’t see the difference between them - no visible boundary separating it into parts.

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

What is a heterogenous mixture

A

Substances all in different phases

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

Mixtures and their individual properties

A

They retain their individual properties/they are not chemically bonded

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

Describe a solid

A

Fixed shape
Can vibrate about a fixed point
Heat can cause enough vibration to overcome attractive forces –> melts

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

Describe a liquid

A

Takes shape of container, fixed volume
Has translational velocity (diffusion)
Heat and pressure of vapour can cause it to boil and evaporate

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

Describe a gas

A

Widely spaced particles, fill container
Pressure in a container is caused by collisions with the container
IMF is negligible

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

Solid to gas

A

Sublimation

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

Gas to solid

A

deposition

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

liquid to gas without boiling

A

vaporization

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

Liquid to solid

A

freezing

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

gas to liquid

A

condensation

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

is vaporization endo or exo

A

endothermic because it absorbs energy to increase kinetic energy to change to a vapour

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

What is avagadros constant

A

6.02 *10^23

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

What is an isotope

A

Same amount of protons and electrons but different mass –> different amount of neutrons

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

Symbol for relative mass

A

Mr

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

Mole to atoms

A

1 mole to 6.02*10^23 atoms

17
Q

mole to mass to molar mass formula

A

n = mass(g) /molar mass (g/mol)

18
Q

Empirical formula

A

The smallest whole number ratio of atoms in an element

19
Q

How to calculate empirical formula given percentage mass

A
  1. assume 100 g total and change each percentage to grams
  2. convert to mols by dividing by molar mass
  3. find ratio between the grams and multiply accordingly
20
Q

How to calculate molecular formula from empirical formula given its molar mass

A
  1. divide given molar mass by the mass of the empirical formula
  2. multiply subscripts by the number found in step 1
21
Q

What is a precipitate

A

insoluble ionic solid

22
Q

Density of liquid formula

A

Mass (g)/Volume (cm^3)

23
Q

Ideal gas law and all of the units

A

PV = nRT
Pressure (1 atm - 1.013 * 10^5 Pa)
Volume (1 m^3 - 1000 litres)
Moles
R constant (8.314 J/K*mol)
Temperature (kelvin)

24
Q

What are moles represented by in an equation

A

the coefficients in front of them

25
Q

what does (aq) mean

A

in aqueous solution

26
Q

Properties of chemical reactions

A
  1. new substances are formed
  2. Bonds in the reactants are broken and bonds int he products are formed resulting in an energy change between the reacting system and its surroundings
  3. There is a fixed relationships between the number of particles of reactants and products –> no overall change in mass
27
Q

What are net ionic equations

A

Only show species between oxidized or reduced - elimination of spectator ions

  1. write molecule equation
  2. write complete ionic equation showing all aqueous species broken down into their ions
  3. cancel out spectator ions that appear on both sides.
28
Q

When to use ionic equations and why

A

When dealing with ionic compounds because they completely dissociate in solution

29
Q

units of concentration/formula

A

C=n/V (mols dm^-3)

30
Q

[ ] meaning

A

concentration

31
Q

At constant temperature what happens between volume and pressure

A

Volume decrease causes increase in gas concentration and pressure from collisions with container walls. Therefore greater pressure. Pressure increase is inversely proportional to decrease in volume

32
Q

when does a gas behave most like an ideal gas?

A

At high temperatures and low pressures

33
Q

At stp what volume does one mol of gas occupy

A

22.7 dm^3 or 22.7 * 10^-2 m^3

34
Q

Atom economy formula

A

atom economy = mass of desired products/mass of all products * 100

35
Q

Magnitude of atom economy meaning

A

high atom economy means that fewer natural resources are used and less waste is created

36
Q

Percentage yield formula?

A

Actual yield/theoretical yield * 100

37
Q

Percentage change formula

A

(Final - initial) / initial * 100

38
Q

percentage error calculation

A

(actual value - expected value)/expected value * 100