Chemistry yr 10

Observation made when Mg (s) + CuSO4 (aq) reacts

• Copper solid turns pink-brown

• MgSO4 solution turns colourless

Observation made when Fe (s) + CuSO4 (aq) reacts

• Copper solid turns pink-brown

• Iron sulfate solution turns pale green

What is ban alkali?

• soluble base

Describe the flame test to test positive ions

• turn Bunsen burner into a non luminous flame

• Pit solo I’d on a nickrome loop, clean in HCl

• Pit solid on flame and observe colour

Colour of flame test for Li+

Crimson red

Colour of flame test for K+

Lilac

Colour of flame test for Na+

Yellow-orange

Colour of flame test for Ba2+

Green-yellow

Colour of flame test for Ca2+

Brick red

Colour of flame test for Cu2+

Green-blue

Describe the hydroxide test to test positive ions

• Add solution to a test tube

• Add NaOH

• Observe colour

Colour of hydroxide test for Cu2+

Blue precipitate

Colour of hydroxide test for Ca2+

White precipitate

Colour of hydroxide test for Fe2+

Green precipitate

Colour of hydroxide test for Fe3+

Brown-Orange precipitate

Colour of hydroxide test for Al3+

White precipitate then redissolves

Colour of hydroxide test for NH4+ Ammonium ion

• NH4+OH → NH3+H2O

• Damp pink litmus paper turns blue as NH3 is an alkali

Describe the Halide test

• add solution to a test tube

• Add nitric acid to remove impurities such as CO3 or OH (Ag2CO3 forms white ppt)

• Add silver nitrate AgNO3 and observe colour

What is the colour for Cl- in halide test?

White ppt

What is the colour for Br- in halide test?

Cream ppt

What is the colour for I- in halide test?

Yellow ppt

Describe the carbonate test

• add solution and acid into test tube, fizzes when CO2 present

• When limewater is added, solution becomes cloudy

Describe the sulfate test

• Add 3cm³ of solution into a test tube

• Add 3cm³ of acid to remove impurities like CO3

• Add 3cm³ of barium chloride BaCl2

• Forms white ppt

• Ba + SO4/CO3 →BaSO4/BaCO3 (both white ppt)

Why does reactivity increases as you go down group 7?

• More electron shells

• Weaker electrostatic attraction between outer electron and positive nucleus

• Outer electron more easily lost

Physical properties of group 7

• shiny

• Good conductor of heat and electricity

• Relatively low density

• Forms basic oxides

• Malleable and ductile

Reaction of lithium with water

• 2Li (s) + 2H2O → 2LiOH + H2

• fizzes , floated and moves around, disappears

Reaction of sodium with water

• 2Na(s) + 2H2O → 2NaOH + H2

• Fizzes, floats and moves around forms a sphere, disappears

Reaction of potassium with water

• 2K + 2H2O → 2KOH + H2

Volume of gas in atmosphere

78%-Nitrogen

21%-oxygen

0.9%-Argon

0.1%-CO2+others

What colour is fluorine at room temperature?

Yellow gas

What colour is chlorine at room temperature?

Green gas

What colour is bromine is room temperature?

orange-brown liquid

What colour is iodine at room temperature?

grey solid

What colour is astatine in room temperature?

Grey solid

What is the test for Cl2?

• damp blue litmus paper

• Turns pink then bleached white

Thermal decomposition of a carbonate such as copper carbonate

• CuCO3 (green) → CuO (black) + CO2

Test for O2

• glowing splint relights