Given the heats of combustion of ethylene, hydrogen and ethane as 337.2, 68.3 and 372.8 kcal respectively, calculate the heat of reaction at 78°C for;
C2H4(g) + H2(g) → CH.(g)
[9 marks]​

Particle model to predict what will happen if a sharp object creates a hole in the soccer ball

Which statements are true concerning mineral formation? check all that apply. the slower the cooling, the larger the crystals. the faster the cooling, the smaller the crystals. crystals formed from magma are smaller than crystals formed from lava. minerals can only form in solutions when the solution is heated deep underground. when a solution cools, elements and compounds leave the solution and crystallize as minerals. minerals formed from hot water solutions can form narrow channels in the surrounding rock.

Why does earth rotate? because earth is formed from cold gases collapsing due to gravity because the matter in the nebula that formed earth was spinning because earth forms more than 99% of the mass of the solar system because the hydrogen atoms inside the nebula fused to form helium