Carl runs 10km in 2 hours. How fast does he run the race

5 km/h

Explanation:

The speed of an object is a scalar quantity telling us "how fast" an object is moving, regardless of its direction of motion.

The speed of an object is given by

where

d is the distance covered by the object, which is the total length of the path covered

t is the time taken

In this problem we have:

d = 10 km is the distance covered by Carl

t = 2 h is the time taken

So, the  speed of Carl is:

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