The combination of coke and steam produces a mixture called coal gas, which can be used as a fuel or as a starting material for other reactions. If we assume coke can be represented by graphite, the equation for the production of coal gas is:

2C(s)+2H2O(g)--->CH4(g)+CO2(g)
Determine the standard enthalpy change for this reactionf rom the following standard enthalpies of reactions:

C(s)+H2O(g)--->CO(g)+H2(g) ΔH=131.3 kJ
CO(g)+H2O(g)--->CO2(g)+H2(g) ΔH=-41.2 kJ
CH4(g)+H2O(g)--->3H2(g)+CO(g) ΔH=206.1 kJ

Match the words in the left column to the appropriate blanks in the sentences on the right. (a) this is the law of definite proportions: all samples of a given compound, regardless of their source or how they were prepared, have proportions of their constituent elements. (b) this is the law of conservation of mass: in a reaction, matter is neither created nor destroyed. (c) this is the law of multiple (c) this is the law of multiple blank: when two elements form two different compounds, the masses of element b that combine with 1 g of element a can be expressed as a ratio of small whole-numbers. in this example, the ratio of \rm o from hydrogen peroxide to \rm o from water = 16: 8 \to 2: 1, a small whole-number ratio.: when two elements form two different compounds, the masses of element b that combine with 1 g of element a can be expressed as a ratio of small whole-numbers. in this example, the ratio of o from hydrogen peroxide to o from water = 16: 8 → 2: 1, a small whole-number ratio.