Which measurements are scalar quantities? (select all that apply) 5 mi northeast 12 km/hr 2 m north 2 m

Answer. 12 km/hr and 2 m are scalar quantities.

Explanation

Scalar quantities are those quantities which only have magnitude but no direction, for example: speed, time, mass etc.

Vector quantities are the quantities which have both magnitude and direction,for example : acceleration, momentum etc.

5 m northeast and 2 m north are vector quantities telling us magnitude and direction both that is 5 m in north east direction and 2 m in north direction.  

12 km/hr and 2 m are scalar quantities telling us only speed and distance respectively without specific directions.

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