Chemistry Questions! Please Help?

Question

#1 For molecules to react, they must collide. An effective collision depends upon-
A. a molecule colliding with the wall of the container
B. three or more molecules colliding
C. Molecules having popular orientation only.
D. Molecules having proper orientation and enough energy
#2 Which of the following factors doesn’t affect the speed of a chemical reaction?
a. size of the beaker in which the reaction proceeds
b. Temperature
c. Nature of the reactants
d. Concentration
#3 A catalyst increases the rate of a chemical reaction by-
a. causing more collisions between molecules
b. increasing the energy of the particles in a reaction
c. lowering the activation energy of a reaction
d. raising the activeation energy so that the colliding molecules have more energy
#4 In a laboratory situation, the best way to determine is an acid or a base is to
A. taste the substance
B. touch the substance
C. test the substance with litmus paper
D. dilute the substance with excess water

Answer 1

#1: D

#2: A*
For a chemist, this is probably the correct answer. For a chemical engineer such as myself, I disagree greatly. When the size of reaction exceeds the little beaker size that chemists know about, there are definite size issues that arise. So, therefore, I content this is the wrong answer, but the correct in a chemistry class.

#3: C

#4: C
(And I disagree here too, the BEST way is to use a pH probe. =) )

Answer 2

1. From a side view of a book, you will notice that there is two sides of the cover and pages. This means that the thickness should be: Thickness = 200 * page length + 2 * cover length = (200*0.10mm)+(2*0.020mm) = 20.04 mm = 2.004 cm 2. Volume = length * width * height = 10cmx2cmx2xm = 40 cm^3 A 2cmx2cmx2cm block is of volume 8 cm^3. If you take the total volume of the metal block and divide it by the volume of each individual block, you should find how many blocks you need: 40 cm^3/8cm^3 = 5 blocks Chemistry questions: - Evaporation is the actual process of taking a substance and converting is from liquid phase to gas phase. Boiling is the point where the pressure exerted by the liquid matches the surrounding pressure, thus causing the substance to begin evaporating. - The higher pressure you have, the tighter the air is packed, and the more the energy of the molecules is contained and conserved. The energy of the molecules, at our level is indicative of heat. Thus, the more pressure exists, the hotter the contained product becomes... which allows for faster and easier cooking (since you are able to hold onto more heat for a longer period of time).

Answer 3

1) D
2) A
3) C
4) C

Answer 4

1. d
2. a
3. c
4. c

Answer 5

1D
2A
3C
4C

Now do your homework