The density of mercury (hg, a liquid metal) is 13.6 g/ml. how much would 18.0 ml of mercury weigh?

Density of Mercury = 13.6 g/ml

Volume of mercury = 18.0 ml

Weight of Mercury = ?

By using the formula

Density = Mass / Volume or

D = M / V

M = D x V

Putting the values of D and V

M = 13.6g/ml x 18.0ml

M  = 244.8 g

So the Mercury weighs 244.8 g

it's all four options.

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