4. A scientist in a laboratory carries out a chemical reaction using 12.01 g of

Question

4. A scientist in a laboratory carries out a chemical reaction using 12.01 g of carbon and 64.14 g or sulfur. The reaction produces 76.15 g of a pure compound. Does this observation agree with an established law of chemical reactions? Why or why not? Answer Explanation: The following graph represents a student's data points after the determination of density from different concentrations of sucrose solutions 5. 1.20 1.10 1.05 1.00 0.95 10 20 30 40 50 60 Concentration (% W:V) a) Use the graph to determine the density of a 12% w/v sucrose solution. Answer Use the graph to determine the concentration of a sucrose solution with a density of g/mL b) 1 Answer c) would you expect the density of a 60% w/v sucrose solution to be higher or lower than 1.20 g/mL? Please explain your choice Answer Explanation

Explanation / Answer

The possible reaction is C(s)+ 2S --------->CS2, 1 mole of C reacts with 2 mole of S tio give 1 mole of CS2.

molar masses : C= 12, S= 32 and CS2= 76

hence 12 gm of C reacts with 64 gm of S to give 76 gm of CS2, a pure compound.

2 Draw a vertical line at 12% to intersect the cuve to give the density which is 1.05 g/ml.

3. at 1.09 g/ml density, draw a horizontal line to intersect the cuve and go verticallly down to find the concentration as 22 wt%.

the density varies as wt%. So 60 wt% can be expected to have density more than 1.2.

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