Question

How much K2Cr2O7 is needed to create a saturated solution in 400 grams of water at 50oC?

Answer 1

Answer:

Approximately 128 g of K₂Cr₂O₇ will saturate 400 g of water.

Explanation:

From Literature and solubility curves, the solubility of K₂Cr₂O₇ at 50°C was obtained to be approximately 32 g/100 mL.

Solubility of K₂Cr₂O₇ in water at 50°C = 32 g/100 mL of water

So, how much K₂Cr₂O₇ will dissolve in 400 g of water?

Density of water = 1 g/mL

So, 1 g of water = 1 mL of water

400 g of water = 400 mL of water.

So, if 100 mL of water dissolves 32 g of K₂Cr₂O₇

400 mL of water will dissolve (32 × 4) g of K₂Cr₂O₇, that is, 128 g of K₂Cr₂O₇.

Hope this Helps!!!!

Answer 2

Answer:

The mass of K₂Cr₂O₇ needed to create a saturated solution in 400 grams of water at 50°C is 120 grams

Explanation:

To answer the question, we will be required to know the solubility of potassium dichromate, K₂Cr₂O₇ in H₂O at 50°C

From the solubility curve, we have, 30 g of K₂Cr₂O₇ will be required to create a saturated solution in 100 g of at 50°C. Therefore, the amount of K₂Cr₂O₇ that will be required to create a saturated solution in 400 g of water, is given by the following equation;

$400 \times \frac{30 \, g \ K_2Cr_2O_7}{100g \ H_2O} = 120 \, g$

Therefore, the mass of K₂Cr₂O₇ needed to create a saturated solution in 400 grams of water at 50°C = 120 grams.