## 50 Questions

What does concentration refer to in chemistry?

The amount of solute in a solution

How is concentration usually expressed?

Mass per unit volume

Which concentration unit is defined as moles of solute per liters of solution?

Molarity (M)

How is mass concentration calculated?

Mass of solute/volume of solution

What does concentration in chemistry refer to?

The amount of a substance in a defined space

How is concentration defined?

The ratio of solute in a solution to either solvent or total solution

In what units can concentration be expressed?

g/cm3, kg/l, M

What methods can be used to express concentration?

Mass concentration, volume concentration

Which solutions have a high amount of solute?

Concentrated solutions

How are concentrated solutions made dilute?

By adding more solvent to the solution

What makes converting units between volume and mass of solution difficult?

Temperature changes

What is the concentration of the solution in milligrams per milliliter?

5 mg/mL

How many grams of carbon dioxide are in 0.2 moles of CO2?

8.802 grams

How would you convert milligrams per liter to molarity?

Molarity = mg/L / (molecular weight of solute) x 1,000

How do you calculate the molarity of a solution in moles per liter, given moles and volume in liters?

Divide the volume by the number of moles

How many moles of potassium chloride (KCl) are contained in 0.25 L of 0.80 mol/L KCl solution?

0.20 moles

What is the molarity of the sugar solution when 4 g of C12H22O11 is dissolved in a 350 ml teacup filled with hot water?

0.033 mol/L

What is the osmolarity of 0.3% saline?

102 mOs

Which solution has the highest osmolarity?

Potassium phosphate

What is the osmolarity of a 10% lipid solution?

258 mOsm/L

What is the osmolarity of a 0.750 M KCl solution?

4000 mOsm/L

How much calcium chloride is required to prepare a 500 ml solution with an osmolarity of 2053 mOsm/L?

1 gram

What is the osmolarity of a 15% amino acid solution (Novamine 15%)?

1388 mOsm/L

How many grams of KCl is required to prepare a 3 molar solution for a volume of 500 ml?

111.75 grams

What is the osmolarity of a solution containing 164 mg of sodium acetate dissolved in 1 liter?

4000 mOsm/L

What is the normality of a solution with 3 mmol phosphorus and 4 meq sodium in each ml?

$7 N$

How much dibasic Na2H2PO4 is present in each ml of sodium phosphate solution?

142mg

What is the molecular weight of calcium gluconate?

430.38 g/mol

What is the concentration of Dextrose when 50g is dissolved in 1000ml?

252 mOsm/liter

How much Aminosyn II 15% amino acid is required to achieve an osmolarity of 4000 mOsm/L in a TPN solution?

50g

What is the main difference between concentrated and dilute solutions?

Concentrated solutions have a high concentration of solute, while dilute solutions have a low concentration of solute

How can non-volatile solvents be concentrated?

By removing solvent through evaporation or boiling

What is the purpose of preparing stock solutions?

To allow for better precision in making dilutions

How is molarity calculated?

By dividing the moles of solute by the volume of the solution in liters

What is one osmole (Osmol) equivalent to?

One mole of particles that contribute to osmotic pressure

In the example blood sample, how does Na+ ions contribute to osmolarity?

[Na+] contributes as NaX (where X is a negative ion)

How can molarity and osmolarity be calculated from mass per unit volume?

By converting mass to moles using molar mass and dividing by the volume in liters

For an ionic compound like NaCl, how many moles of osmotic particles does each mole contribute?

+2 mol

What is the relationship between molarity and osmolarity for an ionic compound?

[Molarity] = [Osmolarity] * 2

What is the formula for calculating molarity?

Mass of solute in grams divided by the volume in liters

How is osmolarity related to the number of osmoles and volume of solution?

Osmolarity is the number of osmoles per liter of solution

If a solution has a molarity of 2.5 M, what would be its osmolarity if it contains an ionic compound?

5 Osmol/L

How can osmolarity be calculated from molarity?

Multiply the molarity by the number of osmoles produced by one mole of solute

What contributes to both molarity and osmolarity calculations for ionic compounds?

The moles of each ion from the compound

What does molarity represent?

The concentration of a solution in terms of moles of solute per liter of solution

How does one mole of an ionic compound affect osmolarity?

It increases osmolarity by 2 Osmol/L

What is used to determine the amount of solute in moles for calculating molarity?

$Moles = \frac{Mass}{Molar Mass}$

What contributes to the osmolarity calculation for a glucose solution?

$Glucose\ (C_6H_{12}O_6)$ molecules

Which factor influences both molarity and osmolarity calculations for sodium chloride solutions?

Dissociation into Na$^+$ and Cl$^-$ ions

What does one mole of calcium chloride contribute to osmolarity?

2 Osmol/L

## Study Notes

- Molarity is the number of moles of solute per liter of solution. For calculating molarity, convert the volume to liters if it is given in milliliters, and determine the amount of solute in moles using the molar mass. Divide the number of moles of solute by the number of liters of the solution to obtain the molarity.
- Example: For an ammonia solution, the volume is 100 mL, and the mass of ammonia is 5.00 g. The molarity is 2.9 M.
- Osmolarity is the number of osmoles per liter of solution, which is the number of particles contributing to the osmotic pressure. One mole of an ionic compound generates two osmoles.
- For instance, a solution of 1 mol/L of sodium chloride (NaCl) has an osmolarity of 2 Osmol/L.
- To calculate osmolarity from molarity, multiply the molarity by the number of osmoles produced by one mole of solute.
- Example: Blood has a sodium concentration of 0.140 mol/L, glucose concentration of 180 mg/100 mL, and BUN (blood urea nitrogen) concentration of 20 mg/100 mL. The osmolarity of blood can be calculated by adding the contributions of Na+, glucose, and BUN.
- Molarity and osmolarity can be calculated from mass per unit volume. For example, a solution containing 40.0 g of sodium chloride (NaCl) in 1.00 L of solution has a molarity of 1.2 mol/L and an osmolarity of 3.6 mol/L.
- Ionic compounds dissociate into ions, contributing the number of moles of each ion to both molarity and osmolarity calculations. For example, 1 mol of NaCl generates 2 mol of osmotic particles (1 mol of Na+ and 1 mol of Cl-).
- Different solutions, such as calcium chloride, calcium gluconate, dextrose, magnesium sulfate, potassium acetate, potassium chloride, potassium phosphate, sodium acetate, and sodium bicarbonate, have various molarities and osmolarities depending on their chemical composition.

Test your knowledge on molarity calculations and unit conversions from milliliters to liters. Understand the steps involved in determining the amount of solute present in a solution in moles when the known amount of solute is in grams.

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