Question

question 8 (1 point)
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if you have weighed out too much solid compound on a balance, you should ...
a) throw it all away in trash and start over.
b) remove the extra compound and put it in the trash can.
c) remove the extra compound and put it in the waste container.
d) remove the extra compound and put it back in the stock bottle.
e) use all of it anyway.

question 9 (1 point)
listen
a silver-colored cube is handed to you. the person wants you to buy it, saying that it is a block of solid platinum. you find that the density of platinum is 21.5 g/cm³. you measure the cube and find that it is 3.5 cm on each side, and weighs 922 g. what is its density?

Explanation:

Question 8

• Option a: Throwing all away is wasteful and not standard lab practice.
• Option b: Trash can is not for lab waste (chemicals need proper disposal).
• Option c: Lab waste containers are for disposing extra chemicals safely, preventing contamination and following lab safety protocols.
• Option d: Putting back risks contaminating the stock bottle.
• Option e: Using excess may affect experiment results.

Step1: Calculate volume of cube

The volume \( V \) of a cube is given by \( V = s^3 \), where \( s \) is the side length. Here, \( s = 3.5 \, \text{cm} \). So, \( V=(3.5)^3 \, \text{cm}^3 \). Calculating \( 3.5\times3.5 = 12.25 \), then \( 12.25\times3.5 = 42.875 \, \text{cm}^3 \).

Step2: Calculate density

Density \(
ho \) is given by the formula \(
ho=\frac{m}{V} \), where \( m \) is mass and \( V \) is volume. Here, \( m = 922 \, \text{g} \) and \( V = 42.875 \, \text{cm}^3 \). So, \(
ho=\frac{922}{42.875} \approx 21.5 \, \text{g/cm}^3 \) (after calculation: \( 922\div42.875 = 21.5 \)).

Answer:

c) remove the extra compound and put it in the waste container.

Question 9