Other Chemistry Answers

16 What would you use to achieve a constant stirring?
Magnetic stirrer
Hot plate stirrer
Mechanical stirrer
Stirrer motor
17 What is the product formed when you dehydrate an alcohol?
Alkene
Alkane
Alkyne
Ester
18 What is the mole fraction of each component if 3.9 g of benzene
(C6H6)
(C6H6)
is dissolved in 4.6 g of toluene
(C7H8)
(C7H8)
?
0.50 each
0.10 each
0.05 each
0.01 each

13 Solids are usually purified by the method of ____________.
fractional distillation
distillation
crystallization
All of the above
14 Which of these helps you to keep solutions at a constant temperature while stirring?
Magnetic stirrer
Hot plate stirrer
Mechanical stirrer
Stirrer motor
15 What is the maximum capacity of the analytical balance?
110 g
210 g
620 g
None of the above

7 Which of these is not a component of the bunsen burner?
Tong
Chimney
Air vent
Needle valve
8 If a procedure tells you to "add about 3 g of ammonium sulphate", which balance would you use?
Analytical balance
Top-loading balance
Spring balance
All of the above
9 Which of these is more suitable for accurate measurement of mass?
Spring balance
Top-loading balance
Analytical balance
None of the above

4 Which of the following can cause error during weighing?
Presence of air currents in the lab
Balance door being open
Non-equilibration of balance
All of the above
5 If you weighed a cold object on the balance, the reading would be _____________.
Higher
Lower
Same
None of the above
6 During the same experiment, one must be careful to always use _____________balance.
Different
Same
Various
None of the above

1 Which of the following is not a laboratory safety rule?
You should never mix acids with bases
You should tie back your long hair
You should never add water to acid
You should never pour chemicals down the sink
2 Which piece of laboratory equipment can be used to store chemicals for a long period of time?
Burrette
Evaporating dish
Beaker
Pippette
3 Which of these is not a correct use of the bunsen burner?
Turn off the gas valve after use
When not using the bunsen burner for a while, open the air-hole
Never leave the flame unattended
Open the air hole slowly

Classify each of the following substances as either a Lewis acid or a Lewis base:
a. Cl-
b. CO32-
c. Na+
d. Br-

. A train is carrying three cars of concentrated phosphoric acid (assume that it is 85% by weight) to deliver it in a manufacturing plant. The train got into an accident and all of the acid were spilled due to derailment. If 150,000 lbs of potassium hydroxide was used to neutralize the acid, what is the amount (in kg) of concentrated phosphoric acid that was spilled due to derailment?
H3PO4 +KOH ® K3PO4+ H2O

A train is carrying three cars of concentrated phosphoric acid (assume that it is 85% by weight) to deliver it in a manufacturing plant. The train got into an accident and all of the acid were spilled due to derailment. If 150,000 lbs of potassium hydroxide was used to neutralize the acid, what is the amount (in kg) of concentrated phosphoric acid that was spilled due to derailment?
H3PO4 + KOH ® K3PO4 + H2O

assuming that the sodium sulphate sample is 100% pure, calculate the volume of 0.25M BaCl2 required to precipitate all the sulphate in it.

Calculate the pH for the following solutions of weak acids and bases, make sure you know if you are dealing with an acid or a base.

0.051 M H2CO3 (Ka = 4.5 * 10-7) pH