To balance a chemical equation it may be necessary to adjust the

Explanation:

The coefficients of a chemical equation are the numbers that you put in front of each reactant and product. They are used to balance the equation and comply with the law of mass conservation.

By adjusting the coefficients you obtain the relative amounts (moles) of each product and reactant, i.e. the mole ratios.

Here an example.

The first information is what is called a word equation. E.g. nitrogen and hydrogen react to form ammonia:

        This equation shows the chemical formulae but it is not balanced. The law of mass conservation is not observed.

So, in order to comply with the law of mass conservation you adjust the coefficients as follow.

        As you see, it was necessary to modify the coefficients. Now the law of conservation of mass is observed and you get the mole ratios:

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.