Brainliesttt asap!me : )
if you were to measure the mass of magnesium and hydrochloric acid before combining them in the test tube, how would that mass compare to the mass of reactants left in the test tube after the reaction? explain your answer and how it corresponds to the law of conservation of mass.

The mass of the products left in the test tube will be less than that of the original reactants.

Explanation

The equation for the reaction is

Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)

 1.0          3.0              3.9             0.1

Assume you started with 1.0 g of Mg.

It will react with 3.0 g of HCl to form 3.9 g of MgCl2 and 0.1 g of H2

.

Mass of reactants = mass of products

        1.0 g + 3.0 g = 3.9 g + 0.1 g

                    4.0 g = 4.0 g

The Law of Conservation of Mass is obeyed.

However, your test tube and its contents will weigh 0.1 g less than it did before the reaction.

Does that contradict the Law of Conservation of Mass? It does not.

One of the products was the gas, hydrogen, and it escaped from the test tube. You weren't measuring all the products, so test tube and its contents weighed less than before.

i believe it is 40–40–20%

explanation:

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.