Chemistry Lab Questions and Answers

Questions

Answers

Why do you use distilled water in your experiments?

Because distilled water has all its impurities removed through distillation.

What is the formula for converting oC to Fahrenheit( F)?

(oC x 1.8) + 32

Formula for converting oF into Celsius

 (oF - 32)  1.8

Formula for converting oC to Kelvin(K)

K = oC + 273.15

Name all the volumetric apparatus used in the lab

Beaker, measuring cylinder, Burette, Pipet, and volumetric flask. (See the attachment)

A student got the following results in his experiment: 14.9g, 14.19g, 14.88g, 14.92g, but the actual weight is 20.90g. How accurate are the student results. And how precise are the results.

The student results are not accurate but precise. Has the precision of  0.05g

Sketch 2 pieces of glassware: one that can report volume to the hundredth place and one that report volume only to one place.

Pipet is precise to hundredth(  and Burette to a tenth .

Take out a 50ml beaker and add 10ml of water. How many significant figures can you report? Which digit contain the uncertain figure.

Report one significant digit. The zero digit contains the uncertain figure

Compare a 50ml beaker and a 50ml graduated cylinder, which is more precise? Why?

Graduated Cylinders. Beakers are not designed for measuring volumes of liquids. They only give rough values

Nugget that looks like Gold has mass of 1.25g. Knowing that the density of real gold is 20.0g/cc and the density of the fool’s gold is only 5.0g/cc, is the nugget gold with cubic dimension of 0.4 cm a fool’s gold or real gold?

Density D =  =   = 19.53g/cc.

It is a Real Gold.

A 10ml sample of alcohol is pipetted into a flask with stopper. The mass is found by difference to be 7.899g. Calculate the density of the liquid.

Density D =  = 7.899/10 = 0.8g/ml.

One digit.

The mass of an unknown rectangular block is 139.43g. If the block measures 5.00cm by 2.55cm by 1.25cm, what is its density?

Density D =  =  = 8.75g/cm3

What is the meaning of the word sublimation.

Solid changing directly into gas without changing to liquid first.