Chemical formulae, equations and calculations

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Question 75

Some spacecraft use UDMH, a compound similar to hydrazine, as a propellant.

UDMH has a composition by mass of $40.0%40.0\%$ carbon, $46.6%46.6\%$ nitrogen, and $13.4%13.4\%$ hydrogen. Calculate the empirical formula of UDMH.

[3]

The relative molecular mass ( $M_r$ ) of UDMH is $60.0$ . What is the molecular formula of UDMH?

[2]

UDMH ( $C2H8N2\text{C}_2\text{H}_8\text{N}_2$ ) reacts with dinitrogen tetroxide ( $N2O4\text{N}_2\text{O}_4$ ) as a propellant. Balance the equation for this reaction:

[\text{C}_2\text{H}_8\text{N}_2 + \underline{\quad}\text{N}_2\text{O}_4 \rightarrow \underline{\quad}\text{N}_2 + \underline{\quad}\text{CO}_2 + \underline{\quad}\text{H}_2\text{O}

[1]

The enthalpy change ( $ΔH\Delta H$ ) for this reaction is $kJ/mol-1800\text{ kJ/mol}$ . State how this value shows that the reaction is exothermic.

[1]

Some spacecraft use UDMH, a compound similar to hydrazine, as a propellant.

UDMH has a composition by mass of $40.0%40.0\%$ carbon, $46.6%46.6\%$ nitrogen, and $13.4%13.4\%$ hydrogen. Calculate the empirical formula of UDMH.

[3]

The relative molecular mass ( $M_r$ ) of UDMH is $60.0$ . What is the molecular formula of UDMH?

[2]

UDMH ( $C2H8N2\text{C}_2\text{H}_8\text{N}_2$ ) reacts with dinitrogen tetroxide ( $N2O4\text{N}_2\text{O}_4$ ) as a propellant. Balance the equation for this reaction:

[\text{C}_2\text{H}_8\text{N}_2 + \underline{\quad}\text{N}_2\text{O}_4 \rightarrow \underline{\quad}\text{N}_2 + \underline{\quad}\text{CO}_2 + \underline{\quad}\text{H}_2\text{O}

The enthalpy change ( $ΔH\Delta H$ ) for this reaction is $kJ/mol-1800\text{ kJ/mol}$ . State how this value shows that the reaction is exothermic.

[1]

Chemical formulae, equations and calculations

Question 75

Markscheme

Chemical formulae, equations and calculations

Question 75

Markscheme

Chemical formulae, equations and calculations

Question 75

Chemical formulae, equations and calculations Questions

Chemical formulae, equations and calculations

Question 75

Chemical formulae, equations and calculations Questions