Question

What is the mass of calcium nitrite in 3M 240 ml solution A) 120 B) 210 C) 100 D) 130

Answer 1

Ответ:

$n(Ca(NO_2)_2)= C(Ca(N0_2)_2)*V(Ca(N0_2)_2) = 3M* 0,24l=0,72 mol\\m(Ca(NO_2)_2)=n(Ca(N0_2)_2)*M(Ca(N0_2)_2) = 0,72*132=95,04 g$

All answers are wrong. But the closest option is "C".

Answer 2

To determine the mass of calcium nitrite in a 3M, 240 ml solution, we first need to understand what the concentration of 3M means. The concentration of a solution is typically given in moles per liter (mol/L).

In this case, the concentration is 3M, which means there are 3 moles of calcium nitrite per liter of solution. Since the volume of the solution is given as 240 ml, we need to convert it to liters by dividing by 1000:

240 ml / 1000 = 0.24 L

Now, we can calculate the amount of calcium nitrite in moles by multiplying the concentration by the volume:

0.24 L * 3 mol/L = 0.72 mol

The molar mass of calcium nitrite (Ca(NO2)2) can be calculated by summing the atomic masses of its constituent elements. The atomic masses are as follows:

- Calcium (Ca) = 40.08 g/mol - Nitrogen (N) = 14.01 g/mol - Oxygen (O) = 16.00 g/mol

Adding up the atomic masses:

Ca(NO2)2 = Ca + (N * 2) + (O * 4) = 40.08 + (14.01 * 2) + (16.00 * 4) = 40.08 + 28.02 + 64.00 = 132.10 g/mol

To find the mass of calcium nitrite in the solution, we multiply the number of moles by the molar mass:

0.72 mol * 132.10 g/mol = 95.112 g

Therefore, the mass of calcium nitrite in the 3M, 240 ml solution is approximately 95.112 grams.

So the correct answer would be:

C) 100 g