Which of the following words best describe scientists current knowledge about the universe a) eternal b) staticc) unpredictable d) changing

The correct answer is "d) changing"

Explanation:

The universe is changing because it is expanding as proven by astronomers such as Hubble. The universe is cooling because of which it is expanding. Space is moving with the speed of light which is explained by Einstein's equation. It is believed that dark energy is causing the universe to expand.

sure im new too!

explanation:

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2