In a laboratory experiment, a 10.0-mL sample of NaCl solution is poured into an evaporating dish with a mass of 24.10 g. The combined mass of the evaporating dish and NaCl solution is 36.15 g. After heating, the evaporating dish and dry NaCl have a combined mass of 25.50 g.
b. What is the molarity (M) of the NaCl solution?

검증된 단계별 안내

Determine the mass of the NaCl solution by subtracting the mass of the empty evaporating dish from the combined mass of the evaporating dish and NaCl solution: \( \text{Mass of NaCl solution} = \text{Mass of dish + solution} - \text{Mass of dish} \).

Calculate the mass of the dry NaCl by subtracting the mass of the empty evaporating dish from the combined mass of the evaporating dish and dry NaCl: \( \text{Mass of dry NaCl} = \text{Mass of dish + dry NaCl} - \text{Mass of dish} \).

Determine the mass of water in the NaCl solution by subtracting the mass of the dry NaCl from the mass of the NaCl solution: \( \text{Mass of water} = \text{Mass of NaCl solution} - \text{Mass of dry NaCl} \).

Convert the mass of dry NaCl to moles using the molar mass of NaCl (\( 58.44 \ \text{g/mol} \)): \( \text{Moles of NaCl} = \frac{\text{Mass of dry NaCl}}{\text{Molar mass of NaCl}} \).

Calculate the molarity (M) of the NaCl solution by dividing the moles of NaCl by the volume of the solution in liters: \( \text{Molarity} = \frac{\text{Moles of NaCl}}{\text{Volume of solution in liters}} \). Remember to convert the volume from milliliters to liters by dividing by 1000.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

영상 길이:

도움이 되었나요?

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Molarity

Molarity (M) is a measure of concentration defined as the number of moles of solute per liter of solution. It is calculated using the formula M = moles of solute / liters of solution. Understanding molarity is essential for determining how concentrated a solution is, which is crucial in laboratory experiments and chemical reactions.

Mass and Moles Relationship

The relationship between mass and moles is governed by the formula: moles = mass (g) / molar mass (g/mol). This concept is vital for converting the mass of a solute into moles, allowing for the calculation of molarity. Knowing the molar mass of NaCl (58.44 g/mol) is necessary to perform these conversions accurately.

Evaporation and Residue

Evaporation is the process of turning a liquid into vapor, which can be used to separate a solute from a solvent. In this experiment, heating the NaCl solution causes the water to evaporate, leaving behind dry NaCl. Understanding this process helps in determining the amount of solute present after evaporation, which is crucial for calculating the molarity of the original solution.