Two chemical reactions are shown:

2mg + o2 → 2mgo
caco3 → cao + co2

which statement is true?

(a) cao is a reactant from second reaction
(b) oxygent act as oksidator in the first reaction
(c) magnesium undergoes reduction reaction
(d) calsium carbonate act as product of the reaction

B

Oxygen acts as oxidator in the first reaction.

Explanation:

At reactant side:

Mg = 0

At product side:

MgO = 0

but Oxygen (O) = -2

Mg + O = 0

Mg + (-2) = 0

Mg - 2 = 0

Mg = 2

Magnesium is oxidized by OXYGEN from zero to +2

Oxygen acts as oxidator in the first reaction.

Oxygen acts as oxidator in the first reaction.

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.

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.