Question

How many total moles of ions are released when the following sample dissolves completely in water? Enter your answer in scientific notation.

6.18 Ã 10â4g of Ca(NO3)2

Answer 1

When 6.18 x 10^-4g of Ca(NO3)2 dissolves completely in water, it produces a total of 1.131 x 10^-5 moles of ions.

Step-by-step explanation:

To find the total moles of ions when 6.18 x 10-4g of Ca(NO3)2 dissolves completely in water, we first need to convert the grams to moles. The molecular weight of Ca(NO3)2 is about 164.10 g/mole. So, the moles of Ca(NO3)2 is 6.18 x 10-4g ÷ 164.10 g/mole = 3.77 x 10-6 moles. Notice that each formula unit of Ca(NO3)2 yields 3 ions (1 Ca2+ and 2 NO3-). Therefore, the total moles of ions when the sample dissolves completely in water is 3 x 3.77 x 10-6 moles = 1.131 x 10-5 moles in scientific notation.

Learn more about Moles of Ions

Answer 2

Total moles of ions are released in water are
`1.131* 10^(-5) mol`.

Step-by-step explanation:

Mass of calcium nitrate =
`6.18* 10^(-4) g`

Molar mass of calcium nitrate = 164 g/mol

Moles of calcium nitrate =
`(6.18* 10^(-4) g)/(164 g/mol)=3.77* 10^(-6) mol`

`Ca(NO_3)_2(aq)\rightarrow Ca^(2+)(aq)+2NO_3^(-)(aq)`

According to reaction, 1 mole of calcium nitrate gives 1 mole of calcium ions, then
`3.77* 10^(-6)` moles of calcium nitrate will give:

`1* 3.77* 10^(-6) mol=3.77* 10^(-6) mol` of calcium ions

According to reaction, 1 mole of calcium nitrate gives 2 mole of nitrate ions, then
`3.77* 10^(-6)` moles of calcium nitrate will give:

`2* 3.77* 10^(-6) mol=7.54* 10^(-6) mol` of nitrate ions

Total moles of ions are released :

`3.77* 10^(-6) mol+7.54* 10^(-6) mol=11.31* 10^(-6) mol\approx 1.131* 10^(-5) mol`