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Flashcards in Key concepts.3 Deck (21):
1

What’s the law of conservation of mass

The total mass of reactants and products stays constant during a chemical reaction. The total mass before and after a reaction is the same

2

What’s a closed system

Is a situation in which no substances can enter or leave during a reaction

3

What can closes systems include

Reactions in a sealed container
Such as a flask fitted with a bung

Precipitation reactions in a beaker

4

What happens in a precipitation reaction?

Two soluble reactants form an insoluble product - the precipitate

For example

NaCl(aq) + AgNO3(aq) -> NaNO3(aq) + AgCl(s) which forms a white cloudy precipitate

Total mass of the beaker and its contents stays the same during the formation of the silver chloride previpiatate

5

What’s a non enclosed system ?

A situation in which substances can enter or leave during a reaction

6

A balanced chemical equations is also called a

Stoichiometric equation

7

The mass of product is directly proportional to the

Mass of the limiting reactent

8

What are th types of reactions

Reaction and limiting reaction

9

What’s a solution

Mixture of a solute in a solvent

10

What’s a solute

The substance which dissolves

11

What’s the solvent

The substance that the solute dissolves in

12

1 dm^3 =

10 x 10 x 10 = 1000cm^3

13

How do you convert cm^3 to dm^3

Divide by 1000

14

What do you need to calculate the concentration of a solution

The mass of the solute in grams

Volume of the solution in cubic decimetres

15

Equation for concentration

In g dm^-3



Mass of solute(g) / volume of solution (dm^3)

16

Why does g dm^-3 mean

Grams per cubic decimetre

Also see it written as g/dm^3

17

What’s the unit for an amount of a substance

A mole

18

The mass of 1 mol of Particles is the

Relative particle mass in grams

19

What is Avogadros constant

6.02 x 10^23 mol^-1

20

The mass of 1 mol of a substance is it’s Ar or Mr in grams these are examples

Carbon, C, Ar, 12 mass of 1 mol=12g

Oxygen, O2, Mr, 32 mass of 1 mol = 32g

21

How do u calculate the amount of a substance from a given mass

Amount (mol) = mass/Ar(Mr)

Moles = grams/rams