What is the molality of a solution containing 200mg of urea molar mass 60 mol 1 dissolved 40g of water?

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The molarity of urea molar mass 60 g mol 1 solution by dissolving 15 g of urea in 500 cm 3 of water is:A. 0.5 mol dm 3B. 2 mol dm 3C. 0.125 mol dm 3D. 0.0005 mol dm 3

6.

If average velocity of a sample of gas molecules at 300 K is 5 cm s-1, what is RMS velocity of same sample of gas molecules at the same temperature? (Given, α: u: v = 1:1.224: 1.127)

• 6.112 cm/s

• 4.605 cm/s

• 4.085 cm/s

• 5.430 cm/s

D.

5.430 cm/s

Given that α (most probable velocity) : u(RMS velocity) : v (average velocity) = 1 : 1. 224 : 1 : 127

∴   uv=  1.2241.127u5=  1.2241.127u= 1.224 × 51.127 = 5.430 cm/s