Pipette Use and Solution Preparation

A tool used for precise handling and dispensing of small liquid volumes, measured in microliters (μL), which are 1/1000 of a milliliter.

A type of pipette that operates by displacing air to draw in and release liquid. It uses disposable tips attached to the pipette.

A range of volumes that a specific pipette can handle, with a minimum and maximum volume. This range is usually indicated on the push button of the pipette.

A measurement of how close repeated measurements are to each other. It indicates the reliability of the measurements.

A measurement of how close a measurement is to the true value. It indicates the accuracy of the measurements.

A solution with a known concentration of a specific substance, used as a standard for comparisons.

A technique used to decrease the concentration of a solution by adding more solvent, maintaining the same amount of solute.

A small, transparent container used to hold samples for spectrophotometric analysis, which measures the absorbance of light.

The amount of a substance dissolved in a given volume of solution.

The substance that dissolves in a solvent to form a solution.

The substance that dissolves the solute to form a solution.

A solution where water is the solvent.

The volume of liquid that is used to dissolve the solute. This is often, but not always, water.

The amount of solute needed to make a desired concentration of solution.

A way to express the concentration of a solution as the mass of solute per 100 grams of solution.

A way to express the concentration of a solution as the volume of solute per 100 milliliters of solution.

A way to express the concentration of a solution as the mass of solute per 100 milliliters of solution.

A unit of concentration that represents the number of moles of solute dissolved in one liter of solution.

The concentration of a solution is independent of temperature changes.

Solutions prepared by dissolving solids in liquids.

Solutions prepared by mixing liquids together.

The amount of a substance dissolved in a specific volume of solution.

The weight of a compound in grams per mole.

The ratio of the initial volume of a concentrated solution to the final volume of a diluted solution.

The volume of liquid required from a concentrated solution to create a desired volume and concentration of a diluted solution.

A process of creating multiple solutions with decreasing concentrations from a stock solution, using fixed volumes.

The weight by volume percentage is the mass of solute per 100 mL solution. To calculate it, we divide the mass of NaCl (5g) by the volume of the solution (50 mL) and multiply by 100%. In this case, (5g / 50 mL) * 100% = 10% weight by volume.

Molarity (M) is the concentration of a solution expressed as moles of solute per liter of solution. To calculate it, we first convert grams to moles and mL to Liters. The molar mass of CaCl2 is 110.98 g/mol. So, 11g of CaCl2 corresponds to 11g / 110.98 g/mol = 0.099 mol. Then, 100 mL is equal to 0.1L. Therefore, the Molarity is 0.099 mol / 0.1L = 0.99 M.

Dilution is the process of decreasing the concentration of a solution by adding more solvent. The amount of solute remains constant, but the volume increases, resulting in a lower concentration. The dilution equation (C1 * V1 = C2 * V2) helps us calculate the volumes needed for different concentrations. C1 represents the initial concentration, V1 the initial volume, C2 the final concentration, and V2 the final volume.

To prepare 100mL of 0.1M NaOH from a 1M NaOH solution, we can use the dilution equation: C1 * V1 = C2 * V2. We know the initial concentration (C1 = 1M), the final concentration (C2 = 0.1M), and the final volume (V2 = 100mL). Plugging these values into the equation, we get: 1M * V1 = 0.1M * 100mL. Solving for V1, we find V1 = 10mL. Therefore, you should use 10mL of the 1M NaOH solution.

To prepare 50mL of 1X NaOH from a 10X NaOH solution, we use the dilution equation: C1 * V1 = C2 * V2. We know the initial concentration (C1 = 10X), the final concentration (C2 = 1X), and the final volume (V2 = 50mL). Plugging these values into the equation, we get: 10X * V1 = 1X * 50mL. Solving for V1, we find V1 = 5mL. Therefore, we need 5mL of the 10X NaOH solution.

When performing dilutions, it is important to ensure that the units on both sides of the equation are the same. For example, if concentration is expressed in moles per liter (M), then volume must be in liters (L). If concentration is in grams per milliliter (g/mL), then volume must be in milliliters (mL). Consistency in units avoids errors in calculations.

A standard solution is a solution with a precisely known concentration prepared from a chemical with a known purity. Standard solutions are typically used for calibration of instruments and for determining the concentration of unknown solutions through reactions or titration.

The accuracy of a measurement refers to how close it is to the true value. It indicates the degree of precision or the reliability of the measurement. A measurement with high accuracy is one that is both precise and close to the true value.

Precision of a measurement refers to the degree of agreement between repeated measurements. A measurement with high precision means that repeated measurements are very close to each other, regardless of whether they are close to the true value.

A pipette is a laboratory tool used for precise handling and dispensing of small volumes of liquids. It draws up a specific volume of liquid with good accuracy. Pipettes are calibrated in microliters (μL), which are 1/1000 of a milliliter.