Question

Обчисліть масу (г) та об'єм (мл) води, який треба взяти для приготування 10 г розчину з масовою часткою 5 %. (пам'ятаємо формулу, що пов'язує масу, об'єм та густину речовини, густина-маса/об'єм, а також те, що густина води рівна 1г/мл). СРОЧНО!!​

Answer 1

m(р-ну) = 10 г

w(реч) = 5%

m(води) - ?

V(води) - ?

Решение:
1) m(води) = 10г - (0,05 * 10г) = 9,5 г

2) V(води) = 9,5 г * 1г/мл = 9,5 мл

Ответ: 9,5 г, 9,5 мл

Answer 2

Calculating the Mass and Volume of Water for a 5% Solution

To calculate the mass and volume of water needed to prepare a 10 g solution with a mass fraction of 5%, we can use the formula that relates mass, volume, and density of a substance. In this case, it's important to remember that the density of water is 1 g/ml.

First, let's calculate the mass of water needed for the solution.

Step 1: Calculate the Mass of Water The mass fraction (w/w) is given by the formula: \[ \text{Mass fraction} = \frac{\text{mass of solute}}{\text{mass of solution}} \times 100 \]

Given: - Mass of solute (m_solute) = 10 g - Mass fraction (w/w) = 5%

We can rearrange the formula to solve for the mass of water: \[ \text{Mass of water} = \frac{\text{mass of solute}}{\text{mass fraction}} - \text{mass of solute} \]

Substitute the given values: \[ \text{Mass of water} = \frac{10 \, \text{g}}{0.05} - 10 \, \text{g} \] \[ \text{Mass of water} = 200 \, \text{g} - 10 \, \text{g} \] \[ \text{Mass of water} = 190 \, \text{g} \]

So, the mass of water needed for the solution is 190 g.

Step 2: Calculate the Volume of Water Now, let's calculate the volume of water needed. Since the density of water is 1 g/ml, the volume of water can be directly obtained from the mass of water.

\[ \text{Volume of water} = \text{Mass of water} \]

Substitute the calculated mass of water: \[ \text{Volume of water} = 190 \, \text{ml} \]

Therefore, to prepare a 10 g solution with a mass fraction of 5%, you would need 190 g of water, which is equivalent to 190 ml.

I hope this helps! If you have any further questions, feel free to ask.