Chemistry Solution Dilution Basics

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Questions and Answers

What is the maximum acceptable concentration of arsenic in ppm?

1.5

0.010

0.025 (correct)

0.050

Which substance has the highest maximum acceptable concentration in ppm?

Lead

Chromium

Fluoride (correct)

Arsenic

What is the maximum acceptable concentration of lead in ppm?

0.025

0.010 (correct)

1.5

0.050

How can combining 50 mL of ethanol with 50 mL of water result in a solution volume of 95 mL?

There is a contraction in volume when mixed. Signup and view all the answers

What is the maximum acceptable concentration of chromium in ppm?

0.050 Signup and view all the answers

Which of the following substances has the lowest maximum acceptable concentration in ppm?

Lead Signup and view all the answers

Which of the following substances has a maximum concentration that exceeds 1 ppm?

Fluoride Signup and view all the answers

Which of the following statements about the mixing of ethanol and water is correct?

It can lead to a decrease in total volume. Signup and view all the answers

What is the volume of DEET in a 250-mL container if the solution has a concentration of 5.0% V/V?

200 mL Signup and view all the answers

What does the % V/V concentration represent in the context of solutions?

The volume of solute per total volume of solution Signup and view all the answers

What is the total volume of the solution if 200 mL of DEET corresponds to a 5.0% V/V concentration?

4000 mL Signup and view all the answers

If a product is diluted to 5.0% V/V, how does this relate to the concentration in parts per million (ppm)?

It results in a very dilute solution Signup and view all the answers

To determine the volume of DEET in a solution, what is the first step?

Identify the percentage concentration Signup and view all the answers

When converting from % V/V to ppm, what aspect should be considered for very dilute solutions?

The total solution volume plays a role Signup and view all the answers

If the concentration of DEET needs to be expressed in ppm instead of % V/V, what aspect must be evaluated?

The dilution factor Signup and view all the answers

What unit of measurement is used for expressing very dilute solutions?

Parts per million (ppm) Signup and view all the answers

What remains constant during the dilution of a solution when more solvent is added?

Amount of solute Signup and view all the answers

If the initial concentration ($C_i$) and volume ($V_i$) of a solute are known, how can the number of moles of solute ($n$) before dilution be calculated?

$n = C_i V_i$ Signup and view all the answers

What is the relationship between initial concentration ($C_i$), final concentration ($C_f$), initial volume ($V_i$), and final volume ($V_f$) during dilution?

$C_i V_i = C_f V_f$ Signup and view all the answers

When adding solvent to a solution, how is the final volume of the solution defined?

Total volume of the solution including solute and solvent Signup and view all the answers

What happens to the concentration of a solution when more solvent is added, assuming the amount of solute remains the same?

It decreases Signup and view all the answers

If the initial concentration of a solute is 2 M and the initial volume is 1 L, how many moles of solute are present?

1 mole Signup and view all the answers

In the dilution equation $C_i V_i = C_f V_f$, which variable indicates concentration after adding solvent?

$C_f$ Signup and view all the answers

Which statement correctly describes what happens when only the solvent of a solution is changed?

The concentration of solute decreases. Signup and view all the answers

What equation would help determine the final concentration of a solute in a solution after dilution?

$C_f = rac{n}{V_f}$ Signup and view all the answers

What is the formula to calculate the number of moles of a substance?

n = m / M Signup and view all the answers

If 30.0 g of NaCl(s) is dissolved in water, how do you determine the number of moles present?

Divide 30.0 g by the molar mass of NaCl. Signup and view all the answers

What is the method for calculating the molar concentration of a solution?

C = n / V Signup and view all the answers

What is the molar concentration of a solution if 0.435 mol of NaCl(s) is dissolved in 200 mL of water?

0.2175 mol/L Signup and view all the answers

How many moles are present in 800 mL of a solution containing 0.674 mol of NaOH(aq)?

0.674 mol Signup and view all the answers

If 5.00 g of NaOH(s) is dissolved in 300 mL of water, what is the first step to find the molar concentration?

Convert grams to moles using the molar mass of NaOH. Signup and view all the answers

What is the molar concentration of sodium sulfate solution if it is calculated to be 0.704 mol/L?

0.704 mol/L Signup and view all the answers

What is the significance of knowing the molar concentration of a solution in scientific industries?

It is used to ensure proper chemical reactions. Signup and view all the answers

What does the symbol % V/V represent in the context of concentration?

The volume of solute as a percentage of solution volume. Signup and view all the answers

Which formula is used to calculate parts per million (ppm)?

g of solute × 10^6 / g of solution Signup and view all the answers

Which concentration method is commonly used by scientists for pure substances?

Molar concentration Signup and view all the answers

For what purpose are agencies that set health and safety standards likely to use ppm?

To communicate levels of pollutants in dilute solutions. Signup and view all the answers

In the formula for percent by volume, which component is multiplied by 100%?

mL of solute Signup and view all the answers

What does a higher molar concentration indicate?

A greater amount of solute relative to solvent. Signup and view all the answers

Which method might be used mainly by manufacturers of consumer products?

Percent by volume Signup and view all the answers

What does the term 'dilute solution' refer to?

A solution where solute concentration is negligible. Signup and view all the answers

Which of the following concentrations is expressed in parts per million?

For every 1 g of solute, there are 1,000,000 g of solution. Signup and view all the answers

Why is molar concentration expressed in moles per liter?

To standardize the amount of solute per volume. Signup and view all the answers

How is parts per million typically expressed mathematically?

mg of solute / kg of solution Signup and view all the answers

What is one primary challenge when using parts per million?

It can be confusing due to its small values. Signup and view all the answers

What does it mean if a solution has a molar concentration of 0.5 M?

There are 0.5 moles of solute per 1 liter of solution. Signup and view all the answers

Which component is NOT involved in calculating percent by volume?

Weight of the solute Signup and view all the answers

Study Notes

Solution Dilution

Addition of solvent to a solution keeps the amount of solute consistent while changing the concentration.
Initial and final concentrations are related via ( C_i V_i = C_f V_f ).
The number of moles of solute before dilution equals the number after dilution: ( n = C_i V_i = C_f V_f ).

Concentration Expression

Percent by Volume (% V/V): expresses the volume of solute relative to the total volume of the solution, used by manufacturers for consumer products.
Parts Per Million (ppm): a unit for very dilute solutions, calculated as ( \text{ppm} = \frac{\text{g of solute}}{\text{g of solution}} \times 10^6 ), often used by health and safety agencies.
Molar Concentration (C): calculated as ( C = \frac{n}{V} ), where ( n ) is the number of moles and ( V ) is the volume of the solution, used in scientific contexts.

Example Calculation

Example of ethanol and water: Combining 50 mL of ethanol and 50 mL of water results in a final volume of 95 mL due to contraction upon mixing.
Molar concentration example: Sodium sulfate solution concentration calculated as 0.704 mol/L.

Molar Concentration Practice Problems

Determining molar concentration involves calculating moles from mass and converting volume from mL to L.
Example:
- Dissolving 0.435 mol of NaCl in 200 mL of water; conversion to molarity needed.
- Calculating moles from 30.0 g of NaCl for an 800 mL salt solution.

Standard Solutions

Industries often require specific concentration solutions for various applications, emphasizing the importance of accurate dilution methods.

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Description

This quiz focuses on the principles of solution dilution, including how the addition of solvent affects concentration while maintaining the amount of solute. Explore key concepts such as percent by volume, ppm, and molar concentration through various calculations and examples.