# Molecular weight of a carotene in carrot can be determined by measuring the osmotic pressure Question 1

Molecular weight of a carotene in carrot can be determined by measuring the osmotic pressure. If 7.68 mg of carotene is dissolved in 10.0 mL of chloroform, the osmotic pressure was 26.57 mmHg at 25 °C. What is the molecular weight of the carotene?

Question 2

Calculate the freezing point of 500. g of water when 25.0 g of CaCl2 is dissolved in it. (Kf(H2O) = 1.86 °C/m).

Question 3

How much heat is absorbed/released when 1.17 mole of NH3(g) reacts in the presence of excess O2(g) to produce NO(g) and H2O(l) according the chemical equation below. 4NH3(g)   +   5O2(g)   →   4NO(g)   +   6H2O(l)       ΔHo = +1168 kJ

Question 4

In acidic solution the dichromate ion, Cr2O7-2, will oxidize Fe2+ to Fe3+ with   formation of Cr3+(see balanced equation below). How many milliliters of 0.100 M K2Cr2O7 is required to oxidize 60.0 mL of 0.250 M FeSO4. 6 Fe2+ + 14 H+ + Cr2O72- → 6Fe3+ + 2Cr3+ + 7H2O

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