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1. Cups made of different materials are sitting on the kitchen counter. Each is

ID: 491309 • Letter: 1

Question

1. Cups made of different materials are sitting on the kitchen counter. Each is filled with hot coffee having the same temperature. Which type of cup will cool the quickest?

glass

ceramic

metal

styrofoam

2. ____ acts as an acid in the following reaction: NH3 + PH3 NH2- + PH4+

Both NH3 and PH3


NH3


PH3


NH2-

3. A floating object will displace _____.

a volume of fluid equal to its own weight

a weight of fluid equal to its volume

a volume of fluid equal to its own volume

a weight of fluid equal to its own weight

4. The following (fake) chemical equation is not balanced: AD2 + R3 A2R2 + D. After balancing, this chemical equation is _____.

Question 36 options:

6 AD2 + 2 R3 3 A2R2 + 6 D2

3 AD2 + 2 R3 3 A2R2 + 4 D

6 AD2 + 2 R3 3 A2R2 + 12 D

A6D12 + R6 A6R6 + 12 D

Explanation / Answer

1) The more is the thermal conductivity , more is the heat loss.

the order of thermal conductivity is metal > glass > ceramic > styrofoam

Thus the order of cooling /heat loss is also in same order.

2.

The reaction is NH3 + PH3 ----> NH2- + PH4+

NH3 loses an electron to give NH2- thus it is an acid

PH3 takes an electron to give PH4+ , thus it is a base.

3)A floating object replaces a weight of fluid equal to its weight. This is Archimedes principle.

4) The balanced equation is

6AD2 + 2R3 -----> 3AR2 +12 D