How much heat energy is required to melt 40g of sodium chloride at its melting point

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?

Hydrogenation reactions, in which h2 and an "unsaturated" organic compound combine, are used in the food, fuel, and polymer industries. in the simplest case, ethene (c2h4) and h2 form ethane (c2h6). if 140 kj is given off per mole of c2h4 reacting, how much heat (in mj) is released when 12 kg of c2h6 forms?