Dissolution of Copper

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Equations:

1) Cu + 4H+(aq) + 2NO3-(aq) Cu2+ + 2NO2 + 2H2O

2) Cu2+(aq) + 2-OH(aq) Cu(OH)2

3) Cu(OH)2 + heat CuO + H2O

4) CuO + H2SO4 Cu2+(aq) + SO42-(aq) + H2O

5) Cu2+(aq) + Zn Cu + Zn2+(aq)

Stage 1- Dissolution of Copper

Mass of vial & copper= 3.537g
Mass of vial= 2.505g
Mass of Copper= 1.032g

Moles of copper= mass (g) ÷ (63.5g/mol)
= 0.0162 mol (3s.f)

Copper description:
Initially, the copper was a solid that was cut into thin strips. It had a shiny/metallic and opaque look, with an orange colour.

HNO3 description:
The nitric acid solution was a transparent, colourless, homogenous liquid.

Notes and observations on the reaction:
Final: Blue solution- homogenous, transparent, low viscosity, liquid
gas generated, heat is released, liquid changes colour- releases nitric oxide, copper ionised- dissolved in liquid, exothermic reaction- generation of heat to the external environment, no energy was provided- energy was taken in the form of heat. Chemical Change. reduction

Where is the copper?
Changed form- it is now dissolved in the blue solution
Changed state- solid to ionised liquid solution- now has a positive charge
Copper sharing 2 electrons with oxygen (aq) Cu2+

Stage 2- Precipitation of Copper Hydroxide

NaOH solution description:
The Sodium Hydroxide liquid was transparent, homogenous, and blue in colour.

Notes and observations on the reaction:
When the sodium hydroxide was added, the solution got a lot darker and had a slight increase in viscosity. It also became heterogeneous as small blue specks were forming and sticking to the glass stirring rod. generating some heat- exothermic reaction, chemical reaction, copper hydroxide was converted to the copper oxide form. reduction

Where is the copper?
In room temperature, the copper hydroxide slowly got suspended, and was floating around in the solution. Cu(OH)2...
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