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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Eric Luu on April 01, 2019, 02:19:46 AM

Title: A few chemistry problems I need help on
Post by: Eric Luu on April 01, 2019, 02:19:46 AM
1. What is the freezing point of a solution of 1.17g of 1-naphthol, C10H8O dissolved in 2.00 mL of benzene at 20 degrees celsius? The density of benzene at 20 degrees celsius is 0.876 g/mL. Kf for benzene is -5.12degrees celsius/m and benzene's normal freezing point is at 5.53 degrees celsius.

2. A 0.0355g sample of an unknown molecular compound is dissolved in 1.000g of liquid camphor at 200.0 degrees celsius. Upon cooling, the camphor freezes at 157.7 degrees celsius. Calculate the molar mass of the unknown compound.

3. Ethylene glycol is effective as an antifreeze but it also raises the boiling temperature of automobile coolant, which helps prevent loss of coolant when the weather is hot. What is the freezing point of a 50% solution of ethylene glycol in water? What is the boiling point of the same 50.0% solution?

4. What is the expected freezing point of an aqueous solution of 2.62 kg of nitric solution HNO3 in a solution with a total mass of 5.91kg? Assume that the nitric acid is completely ionized.

I don't know what to do and how to show my work. I'm at a loss.
Title: Re: A few chemistry problems I need help on
Post by: Borek on April 01, 2019, 02:45:48 AM
What equations that are relevant to these problems do you know?
Title: Re: A few chemistry problems I need help on
Post by: Eric Luu on April 01, 2019, 02:55:33 AM
Delta T=i x k x m

I've finished the first and second one.