1. If 25 grams of Iron (III) hydroxide is dissolved in a 500mL volumetric flask, what is the Molarity of the solution?
2. An unknown metal has a volume of 5.25 mL and a density 2.71 g/mL. What is
the weight of the metal in grams?
3. An unknown metal, heated to an unknown temperature until a liquid is dropped into a calorimeter that has 250 ml of water. The water heats up from 22 degrees Celcius to 29 degrees Celcius, at which point the temperature of the water and metal are equal. How much energy in Kilojoules did the metal release?
4. After subtracting the weight of the container, the Vanadium metal inside is
found to weigh 8.34 grams. After reacting with Oxygen the newly formed
compound weighs 21.43 grams. What is the empirical formula?
5. A 19.18 mL of 0.125 M Oxalic Acid (H2C2O42H2O) is titrated with a Ca (OH)2 solution. The initial volume of Ca(OH)2 was 14.38 and the final volume of Ca(OH)2 was 28.29 mL when the solution turned very slightly pink. What is the concentration of Ca (OH)2?
Thank you!
1. If 25 grams of Iron (III) hydroxide is dissolved in a 500mL volumetric flask, what is the Molarity of the solution?
please only one problem to a post. They get too long when you have more than 1.
moles = grams/molar mass.
You have grams and molar mass, solve for moles.
M = moles/L
You have moles and L, solve for M. By the way, Fe(OH)3 is VERY insoluble in water; the only way to dissolve it would be with an acid or a complexing agent.
1. To find the molarity of the solution, we need to know the number of moles of Iron (III) hydroxide present in the solution. The formula for calculating molarity is:
Molarity (M) = moles of solute ÷ volume of solution (in liters)
First, let's calculate the number of moles of Iron (III) hydroxide. We can do this by using the formula:
moles = mass ÷ molar mass
The molar mass of Iron (III) hydroxide is calculated by adding the atomic masses of the elements present in the compound. Iron (III) hydroxide has one iron atom (Fe) with a molar mass of 55.85 g/mol, three oxygen atoms (O) with a molar mass of 16.00 g/mol each, and three hydrogen atoms (H) with a molar mass of 1.01 g/mol each.
Molar mass of Iron (III) hydroxide = (1 x 55.85) + (3 x 16.00) + (3 x 1.01)
Next, substitute the given mass and the calculated molar mass into the moles formula:
moles = 25 g ÷ molar mass of Iron (III) hydroxide
Now that we have the moles of Iron (III) hydroxide, we can calculate the molarity using the given volume:
Molarity = moles of Iron (III) hydroxide ÷ 0.5 L
2. To find the weight of the metal in grams, we can use the formula:
weight = volume x density
Substitute the given values into the formula:
weight = 5.25 mL x 2.71 g/mL
3. To calculate the energy released by the metal, we need to use the equation:
q = m * c * Δt
where q is the energy released, m is the mass of the water, c is the specific heat capacity of water (which is approximately 4.18 J/g°C), and Δt is the change in temperature of the water.
First, find the mass of the water using the density formula:
mass = volume x density
Substitute the given values into the formula:
mass = 250 mL x (1 g/mL)
Now, calculate the change in temperature:
Δt = final temperature - initial temperature
Substitute the given temperatures into the formula:
Δt = 29°C - 22°C
Finally, substitute the calculated values into the energy equation:
q = mass x c x Δt
Convert the energy from joules to kilojoules by dividing by 1000.
4. To find the empirical formula, we need to determine the ratio of Vanadium to Oxygen in the compound. Start by finding the mass of Vanadium and Oxygen separately.
For Vanadium, subtract the weight of the container from the total weight to find the weight of Vanadium:
weight of Vanadium = total weight - weight of container
For Oxygen, subtract the weight of Vanadium from the total weight to find the weight of Oxygen:
weight of Oxygen = total weight - weight of Vanadium
Next, convert the weights of Vanadium and Oxygen to moles using the molar masses of each element. Divide each weight by the molar mass:
moles of Vanadium = weight of Vanadium ÷ molar mass of Vanadium
moles of Oxygen = weight of Oxygen ÷ molar mass of Oxygen
Finally, divide both moles by the smallest value obtained to find the ratio of moles between Vanadium and Oxygen. This will give you the empirical formula.
5. To find the concentration of Ca(OH)2, use the equation:
Molarity (Ca(OH)2) = moles of Ca(OH)2 ÷ volume of solution (in liters)
First, calculate the moles of Ca(OH)2 using the molarity equation:
moles of Ca(OH)2 = Molarity (Oxalic Acid) x volume of Oxalic Acid (in liters)
Next, set up a balanced chemical equation for the reaction between Ca(OH)2 and Oxalic Acid to determine the mole ratio:
Ca(OH)2 + H2C2O4 -> CaC2O4 + 2H2O
From the balanced equation, you can determine the mole ratio between Ca(OH)2 and Oxalic Acid.
The final step is to substitute the values obtained into the molarity equation to find the concentration of Ca(OH)2.