What is the solubility of K2Cr2O7 in water at 20 °C?

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Discussion Overview

The discussion revolves around the solubility of potassium dichromate (K2Cr2O7) in water at 20 °C, specifically addressing a homework problem related to determining whether a given solution is dilute, saturated, or supersaturated based on its composition.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant states that the solubility of K2Cr2O7 in water is 125 g/L at 20 °C and presents a scenario involving 6.0 grams of K2Cr2O7 in 50 mL of water.
  • Another participant asks for the solubility expressed in grams per milliliter (gm/ml) and the concentration of the prepared solution in the same unit.
  • A participant clarifies that "gm" refers to grams and emphasizes the importance of using consistent units for comparison.
  • There is a request for guidance on how to find the solubility and concentration, indicating uncertainty about the problem-solving process.
  • Another participant points out the given solubility of K2Cr2O7 in water as 125 g/L again, suggesting a focus on this value for calculations.
  • A later reply offers a hint about calculating the equivalent amount of K2Cr2O7 that would dissolve in 1 L of solution based on the provided data.

Areas of Agreement / Disagreement

Participants express uncertainty about the problem-solving approach, and while some agree on the solubility value, there is no consensus on how to proceed with the calculations or the characterization of the solution.

Contextual Notes

Participants have not fully resolved the steps needed to calculate the concentration or compare it to the solubility, and there are missing assumptions regarding unit conversions and the interpretation of the problem.

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Homework Statement


5. The solubility of K2Cr2O7 in water is 125 g/L at 20 °C. A solution is prepared at 20 °C that contains 6.0 grams of K2Cr2O7 in 50. mL of water.
This solution is (A) dilute. (B) saturated. (C) supersaturated. (D) unsaturated.

Homework Equations

The Attempt at a Solution


Hi! I'm trying to study for my chemistry final and I have no memory of working problems like this. I feel like we might of just briefly talked about this in class. I know the answer is D, but I don't know how to work this problem. Could someone please point me in the right direction?
 
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What is the solubility in gm/ml?
What is the concentration of your solution in gm/ml?

Chet
 
What is gm? :(
 
Chet means gram.

Generally the question is about having both solubility and concentration of the prepared solution expressed using the same unit (whatever you choose) and comparing both numbers.
 
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Oh ok. So how do you find the solubility and concentration?
 
jdawg said:
how do you find the solubility

Have you read the problem?

jdawg said:
The solubility of K2Cr2O7 in water is 125 g/L
 
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I'm panicking about this exam man, my mind is clouded. No need to be sassy.
 
Hint: if there are 6.0 grams of K2Cr2O7 in 50. mL of water, how many grams would be in 1 L of identical solution?

Alternatively, if 125 grams dissolve in 1 L, how many grams will dissolve in 50 mL?
 
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