What will be the percent composition by weight of a solution made by dissolving 12.0 g of zinc nitrate, Zn(NO3)2, in 45.0 g of water?

Zn(NO3)2_____________

H2O _____________

57 g total

12/57 and 45/57 fractions.

To find the percent composition by weight of a solution, you need to divide the mass of each component by the total mass of the solution and multiply by 100.

First, let's find the mass of zinc nitrate, Zn(NO3)2:

12.0 g (mass of Zn(NO3)2)

Next, let's find the mass of water, H2O:

45.0 g (mass of water)

Now, let's calculate the percent composition by weight of each component:

Percent composition of Zn(NO3)2:
= (mass of Zn(NO3)2 / total mass of solution) * 100
= (12.0 g / (12.0 g + 45.0 g)) * 100
= (12.0 g / 57.0 g) * 100
≈ 21.05%

Percent composition of H2O:
= (mass of H2O / total mass of solution) * 100
= (45.0 g / (12.0 g + 45.0 g)) * 100
= (45.0 g / 57.0 g) * 100
≈ 78.95%

Therefore, the percent composition by weight of the solution is approximately:

Zn(NO3)2: 21.05%
H2O: 78.95%

To find the percent composition by weight of a solution, you need to determine the mass of each component and calculate the percentage of that mass in the total mass of the solution.

First, let's calculate the mass of each component:

1. Zn(NO3)2 (Zinc Nitrate):
Given that the mass of zinc nitrate is 12.0 g.

2. H2O (Water):
Given that the mass of water is 45.0 g.

Next, we can calculate the total mass of the solution:

Total mass = mass of Zn(NO3)2 + mass of H2O

Total mass = 12.0 g + 45.0 g

Now we can calculate the percent composition by weight:

Percent composition of Zn(NO3)2 = (mass of Zn(NO3)2 / total mass) * 100

Percent composition of Zn(NO3)2 = (12.0 g / (12.0 g + 45.0 g)) * 100

Percent composition of Zn(NO3)2 = (12.0 g / 57.0 g) * 100

Finally, we can calculate the percent composition of water:

Percent composition of H2O = (mass of H2O / total mass) * 100

Percent composition of H2O = (45.0 g / (12.0 g + 45.0 g)) * 100

Percent composition of H2O = (45.0 g / 57.0 g) * 100

Therefore, the percent composition by weight of the solution is:

Zn(NO3)2: (12.0 g / 57.0 g) * 100 = 21.05%

H2O: (45.0 g / 57.0 g) * 100 = 78.95%

So, the percent composition by weight of the solution is approximately:

Zn(NO3)2: 21.05%
H2O: 78.95%