National 5 Chemistry Unit 1 Chemical Changes & Structure

The graph below shows the variation of concentration of a reactant with time as a reaction proceeds. Calculate the average rate of reaction in mol l^-1s^-1  for the  first 25s

How long does it take for the concentration to decrease to 75% of its original value?

• 4 seconds

• 2 seconds

• 8 seconds

• 6 seconds

Identify the atom with 10 neutrons

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Identify the 2 isotopes

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Identify the 2 ions with an electron arrangement of 2,8,8

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Identify the 2 atoms which have 8 protons

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Identify the simple covalent molecule

• A

• B

• C

• D

Identify the covalent network compound

• A

• B

• C

• D

Identify the substance which could be sodium chloride?

• A

• B

• C

• D

Calculate the formula mass in grams of

 

Magnesium sulfate