ASsIghmentamatter medstremens You must show ALL calculations to receive credit (
ID: 1028721 • Letter: A
Question
ASsIghmentamatter medstremens You must show ALL calculations to receive credit (attach a sheet, if necessary). Simply writing the answer will earn you ZERO credit!! Record your answer on the scantron provided using a 1B pencil. Ensure that you bubble in your full name Questions 1 to 10 are worth 1 point each Questions 11- 20 are worth 2 pts each. 1. When the value 4.449 is rounded to two significant figures, the number should be reported as: A) 4.4 B) 4.5 C)4.44 D) 4.45 2. If you hold a solid piece of pure gallium metal in your hand, your body heat will melt the gallium into its liquid form. This illustrates which of the following? A) physical property B) physical change C) chemical change D) chemical property 3. The correct number of significant figures in the number is 0.02790 A) 7 B) 6 C) 5 D) 4 E) ambiguous 4. The correct number of significant figures in the number 4.0 x 102 is: A)1 B) 2 C) 3 D) ambiguous 5. Determine the answer to the following equation with correct number of significant figures: (4.123 x 0.12) + 24.2 = A) 25 B) 24.695 C 24.70 D24.7 6. Which of the following is NOT an example of matter? A) a pencil eraser B) a balloon full of helium C) a dust particle D) heat from a burning candle E) none of the above 7. Which of the following is the lowest temperature? A) 37°C B) 54°F C) 313 K D) All of these temperatures are all equal 8. A substance has a freezing point of -20°C. This is an example of a: 2 chemical property D) chemica hange A) physical property B) physical change Which of the following is a chemical property of water? A) Ice floats B) Water boils at 100°C C) Water reacts violently with sodium. D) All of these are chemical properties 9.Explanation / Answer
1) 4.449 is rounded to 2 significant figures as 4.45 (3rd decimal point is greater than 5 so prior to that number should be rounded off).
2) Pure gallium metal is melted in the hands as our body heat is enough to melt it is a physical property.
3) significant figures in 0.02790 is 4.(non zeros significant and trailing zero is significant)
4) significant figures in 4.0 x 10-2 is 2 (it ccan be written as 0.040 where 2 are significant)
5) (4.123 × 0.12)+24.2 = 24.69476 the correct significant figures is 24.695
6) Heat from burning candle is not a matter as it can be weighed.
7) 54oo F is lowest temperature 37 C = 98.6 F and 313 K = 103.73 F
8) A substance have a freezing point of -20o C is a physical property.
9) Chemical property of water is that water reacting with sodium whereas others are physical properties