Astudent determined the heat of fusion of water to be 88 calories per gram if the accepted value is 80 calories per gram, what is the students percent error?

In this synthesis reaction what products will form

Which real-world scenarios below represent physical and chemical changes? -running a car -exploding fireworks -mixing water and powdered drink mix -combining oil and vinegar to make salad dressing -taking aspirin for a headache -diluting bleach with water-digesting dinner-spreading peanut butter on bread

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