C2- Chemistry

Created by: Emily
Created on: 25-04-13 18:36

Why does Sodium Chloride have a high melting point?

1. It has a giant lattice structure with positively and negatively charged ions. 2. Electrostatic forces or attraction between ions are strong. 3. Large amounts of energy is needed to make ions mobile.

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The balance used to measure the mass of flask with hydrochloric acid and marble chips in. Why does this balance need to have a high resolution?

Gas escapes from the flask, the balance needs a high resolution to measure the small changes in mass.

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Amphetamine: C9H13N. The relative molecular mass (Mr) of amphetamine is 135. Calculate the percentage mass of nitrogen in the drug. (Ar: C=12, H=1, N=14)

C=12x9=108, H=1x13=13, N=14x1=14. (14/135)x100=10.4% nitrogen

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Explain how chromium ions are removed from the water?

The chromium ions form a solid/precipitate which can be removed by filtration.

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Explain why ammonia has a low boiling point?

Ammonia is a simple structure and has weak intermolecular forces.

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Where on the pH scale are hydroxides? Acid, Neutral or alkali?

Alkali (from pH 9 -14).

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Explain why bronze is harder than pure copper?

1. Copper atoms are in layers. 2. Copper is soft because layers can slide. 3. The tin atoms in bronze have distorted these regular layers. 4.Bronze is harder than copper because the metal atoms cannot slide over each other.

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Describe and explain how plastic bottles made with a thermosoftening plastic can be changed into new plastic objects.

1. Used plastic bottles are melted/heated. 2. Then moulded into a new object. 3. Because polymer chains in the plastic have weak intermolecular forces. 4. That allow these polymer chains to become mobile when heated.

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Other cards in this set

Card 2

Front

The balance used to measure the mass of flask with hydrochloric acid and marble chips in. Why does this balance need to have a high resolution?

Back

Gas escapes from the flask, the balance needs a high resolution to measure the small changes in mass.

Card 3

Front

Amphetamine: C9H13N. The relative molecular mass (Mr) of amphetamine is 135. Calculate the percentage mass of nitrogen in the drug. (Ar: C=12, H=1, N=14)