C2: Fundamental Ideas (2) Flashcards Preview

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Flashcards in C2: Fundamental Ideas (2) Deck (16):
1

Ions

A charged particle produced by the loss/gain of electrons.

2

What sort of ions do metals form?

Positively charged ones.
(atoms lose electrons)

3

What sort of ions to non-metals form?

Negatively charged ones.
(atoms gain electrons)

4

Ionic Bonds

The electrostatic force of attraction between positively and negatively charged ions.

5

Relative Atomic Mass

The average mass of the atoms of an element compared with carbon 12.

6

Relative Formula Mass

The total of the relative atomic masses, added up in the ratio of the chemical formula of a substance.

7

Mole

The amount of substance in the relative atomic or formula mass in grams.

8

No of Moles =

Mass (g) / Ar or Mr

9

To calculate the percentage of an element in a compound:

> Work out the Mr of your compound, writing down the Ar of each element separately as you go.
> Divide the Ar of your element by the total Mr of the compound.
> x 100

10

To find an empirical formula:

> Divide the amount of each element by its Ar.
> Put what you get into a ratio.
> Divide all of them by the smallest no. in the ratio.
> Make a formula.

11

Total Mass of Products =

Total Mass of Reactants

12

Aqueous Solutions

Mixture made by adding a soluble substance to water.

13

Litmus + Acid

Red

14

Litmus + Alkali

Blue

15

Percentage yield of a chemical reaction =

amount of product produced/ maximum amount of product possible (x100)

16

Why might a percentage yield be less than it should be?

> Reaction might be reversible
> May have given unexpected products in alternative reactions.
> Some might be lost whilst handling apparatus.
> Lost during separation from reaction mixture.