Asubstance made of two or more elements chemically combined in a set ratio or proportion is called what?

It has been two weeks since charles met with daniel, a dietitian, who provided charles with a menu for weight loss. charles and his mother are going back to see daniel again with a chart of the food charles has eaten. the following lists what charles ate in one day: breakfast 1 banana, 1 cup of nonfat milk, 1 egg lunch 1 cup of carrots, 3 oz of steak, 1 apple, 1 cup of nonfat milk dinner 6 oz of skinless chicken, 1 baked potato, 3 oz of broccoli, 1 cup of nonfat milk

Butadiene undergoes a reaction at a certain temperature in the gas phase as follows: 2c4h6(g) --> c8h12(g) the following data were collected for this reaction: time (min) [c4h6] (m) 0 0.36 15 0.30 30 0.25 48 0.19 75 0. determine the order of the reaction and the rate constant. 1st order and k = 4.3x10 -4 s-1 1st order and k = 2.3x10-4 s-1 2nd order and k = 4.3x10-4 s-1 2nd order and k = 2.3x10-4 s-1 zero and k = 4.3x10-4 s-1

2. how is heavy water different from normal water