Keesha performed a chemical reaction and the products looked quite different from the reactants. She knew the amount of matter had not changed due to the law of conservation of mass. According to the law of conservation of mass, what happens in a chemical reaction?

the spotlight effect.

Explanation:

The spotlight effect is a tendency to think that people get noticed more often than they really do. It is an overestimation of the situation regarding the concern of getting observed. It concerns the self-confidence of an individual. For example, an individual feels that everybody in a party would notice him for a bad pair of shoes while in reality, it does not concern them.

As per the question, the overestimation of people's reaction is known as the spotlight effect.

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.