Percent concentration of solution - preparation of solutions in practice - Percent concentration of solution - preparation of solutions in practice

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Link to the lesson

Before you start you should know

that the molecular dispersion consists of the solvent and the substance dissolved in it;
that the solvent is water in aqueous solutions;

You will learn

calculate the percent concentration of the solution based on its mass or mass of solvent and mass of solute;
estimate the mass of the solution based on the percent concentration of solution and the mass of solute;
determine the mass of solute based on the percent concentration and mass of the solution.

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Nagranie dostępne na portalu epodreczniki.pl

Nagranie audio prezentujące stężenia procentowe.

Preparation of a solution with a specified concentration

Task 1

Watch the presentation „Steps of solving a task”. Pay attention to the methods of calculating the percent concentration of the solution.

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Ilustracja przedstawia napis Stages of solving the task. — How to calculate the percentage of solution? Let's check the example.
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

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Ilustracja przedstawia szklankę wypełnioną wodą do połowy. Obok szklanki znajduje się szklany spodek na którym leży metalowa łyżeczka. — In 170 grams of water, 30 grams of sugar were dissolved. Calculate the percentage concentration of the solution obtained.
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

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Ilustracja przedstawia napisy w dwóch ramkach. W pierwszej ramce napis: Known: mw(mass of water)= 170g, ms( mass of sugar)= 30g. W drugiej ramce napis: Unknown: Cp(percentage concentration)=? — We are writing out data and searched based on the content of the task.
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

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Ilustracja przedstawia wzór: Calculation mr( mass of solution)= m w (mass of water)+ ms (mass of sugar). mr= 170g+ 30 g=200g. — Knowing the mass of substance and solvent, in this case the mass of water, we can calculate the mass of the solution according to the formula and substitute the data we have.
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

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Ilustracja zawiera napis First method. — Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

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Ilustracja przedstawia dwa wzory. Pierwszy wzór cp= ms(mass of solute)/ mr(mass of solution) X 100%. Drugi wzór cp = 30 g/200gX100%= 15%. — The percentage concentration can be calculated in two ways. In the first method, already discussed, we use the formula for calculating the percentage concentration and substitute the data. Answer: the percentage of the solution is 15%.
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

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Ilustracja zawiera napis second method. — Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

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Ilustracja przedstawia wzór dwa wzory. Pierwszy 200g/30g= 100%/x. Drugi wzór x= 30g x 100%/200 g= 15% — In the second method, the concentration of the solution is obtained using the proportions and definitions of the percentage concentration. 200 grams of the solution is 100%. 30 grams of substance is x%. Or 200 grams of the solution contains 30 grams of substance. 100 grams of solution contains X g of substance.
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

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Ilustracja przedstawia dwa wzory. Pierwszy wzór 200g/100g = 30g/xg. Drugi wzór xg= 100g x 30g/200 g =15% — In 100 grams of the solution there is 15 grams of solute, i.e. the percentage concentration of the solution is 15%.
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

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Nagranie audio prezentujące stages of solving the task.

Przygotowanie 150 g wodnego roztworu chlorku sodu o stężeniu 2%

Experiment 1

Familiarize yourself with the steps necessary to prepare a solution with a certain percent concentration. Prepare 150 g of a 2% aqueous sodium chloride solution.

You will need

beaker,
measuring cylinder,
glass rod,
teaspoon,
laboratory scale,
water,
sodium chloride.

Instruction

Before preparing a solution with a given mass and concentration, calculate the mass of solute and the volume of solvent. Our task is to prepare 150 g of a 2% solution. It consists of 147 g of water and 3 g of sodium chloride.
We convert the mass of water into volume.
We measure out the determined volume of water using a measuring cylinder.
Weigh 3 g of sodium chloride on the analytical balance.
Add a weighed amount of sodium chloride to the beaker, add a measured volume of water; mix the ingredients with a glass rod until the substance is completely dissolved.

Summary

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Observations

Conclusions

To prepare a solution with a certain concentration, you need to know the mass of its constituents: solvent and solute. For this purpose, appropriate calculations must be made in advance. Then individual substances are weighed and mixed together.

To prepare 150 g of a 2% aqueous sodium chloride solution, measure the appropriate volume of water and weigh the appropriate amount of sodium chloride (see table below).

Type of solution	Mass of sodium chloride	Volume of water
150 g 2%	$m_{s} = \frac{c_{p} \cdot m_{r}}{100%} = \frac{2% · 150 g}{100%} = 3 g$	Mass of water: ${m_{solv.} = m}_{r} – m_{s} = 150 g – 3 g = 147 g$ Volume of 147 g of water: density of water: $d = 1 \frac{g}{{cm}^{3}}$ $V_{water} = \frac{m_{water}}{d_{water}} = \frac{147 g}{d=1 \frac{g}{{cm}^{3}}} = 147 {cm}^{3}$

Using a measuring cylinder, measure 147 cmIndeks górny 3 of water and pour it into the beaker. Weigh 3 g of sodium chloride on the scale and dissolve it in water.

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Ilustracja przedstawi wagę laboratoryjną na której znajduje się trzy gramy soli (na ce cl) oraz menzurkę napełnioną 147 milimetrami wody (ha dwa o).

Task 2

Calculate how many grams of sugar and how much water do you need to get 400 g of 4% solution?

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Result

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Exercise 1

Calculate how many grams of table salt and how much water should you take to get 300 g of 5% solution?

285 g of water and 15 g of salt
300 g of water and 20 g of salt
285 g of water and 25 g of salt

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Exercise 2

Pair the term with an explanation.

Mass percentage of solute in relation to the weight of the solution, A solution with a low solute content, A solution with a high content of solute, The solute content in the given amount of solution

Diluted solution
Concentration
Concentrated solution
Percent concentration

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Prepare a task to calculate the percent concentration of the solution for your friend. List four answers, including one that is correct.

Question: ...

Summary

Percent concentration is the information about how many parts of the mass (in weight) of the dissolved substance are found in 100 parts of the mass (in weight) of the solution.
The percent concentration of a solution can be calculated based on the weight of the solution and the weight of the solute, using the formula: $c_{p} = \frac{m_{s}}{m_{r}} · 100%$ .
The mass of solute can be calculated based on the percent concentration and mass of the solution: $m_{s} = \frac{c_{p} \cdot m_{r}}{100%}$ .
The percent concentration of the solution can be calculated based on the weight of the solvent and the weight of the solute, using the formula: $c_{p} = \frac{m_{s}}{m_{solv.} + m_{s}} · 100%$ .
If the density of the solution is known, it is possible to determine the mass of given volume.

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Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

Homework

Task 3.1

A child who had an allergy to a wasp venom had anaphylactic shock after being stung by an insect. The rescue is intramuscular administration of the adrenaline solution. This drug is available in ampoules, in a 0.1% solution with a density of 1 $\frac{g}{{cm}^{3}}$ . It is given to children at a dose of 10Indeks górny -6 g per 1 kg of body weight. The endangered child weighs 25 kg. Calculate the volume (cmIndeks górny 3) of this medication that the nurse must administer to the little patient to save his life. Calculate how many cmIndeks górny 3 of the adrenaline solution would have to get your body if your life would be at risk due to a violent reaction to the allergen.

Keywords

percent concentration of the solution, solution, solvent, mass of the solution, density of the solution

Glossary

percent concentration of the solution

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Nagranie słówka percent concentration of the solution.

stężenie procentowe roztworu – liczba gramów substancji rozpuszczonej w 100 g roztworu (wyrażona w procentach)

Lesson plan (Polish)

Percent concentration of solution - preparation of solutions in practice

Preparation of a solution with a specified concentration

Summary

Keywords

Glossary