Question

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How many moles of sodium nitrate are in 0.25 L of 1.2 M NaNO3 solution?

Answer 1

`\boxed {\boxed {\sf 0.3 \ mol \ NaNO_3}}`

Step-by-step explanation:

Molarity is a measure of concentration in moles per liter.

`molarity= (moles \ of \ solute)/(liters \ of \ solution)`

The molarity of the solution is 1.2 M NaNO₃ or 1.2 moles NaNO₃ per liter. There are 0.25 liters of the solution. The moles of solute are unknown, so we can use x.

• molarity= 1.2 mol NaNO₃/L
• liters of solution=0.25 L
• moles of solute =x

`1.2 \ mol \ NaNO_3/L= (x)/(0.25 \ L)`

We are solving for x, so we must isolate the variable, x. It is being divided by 0.25 liters. The inverse of division is multiplication, so we multiply both sides by 0.25 L.

`0.25 \ L *1.2 \ mol \ NaNO_3/L=(x)/(0.25 \ L) *0.25 \ L`

`0.25 \ L *1.2 \ mol \ NaNO_3/L=x`

The units of liters cancel, so we are left with the units moles of sodium nitrate.

`0.25 *1.2 \ mol \ NaNO_3=x`

`0.3 \ mol \ NaNO_3=x`

There are 0.3 moles of sodium nitrate.