I only b. 2 only c. 3 only d. 1-and2 e. 2 and3 12. Te basic unit oflength In the

Question

I only b. 2 only c. 3 only d. 1-and2 e. 2 and3 12. Te basic unit oflength In the metric system is the a. Newton b. liter c. em d. meter e. Angstrom Which of the following observations is/are examples of physical change? 1. The density of water decreases when it solidifies. 2. Aluminum melts when heated above 660 °C -13. 3. Hydrogen peroxide (H,02) decomposes to water and oxygen a. 1 only b. 2 only c. 3 only d. 1 and 2 e. 1,2, and 3 Which three elements are likely to have similar chemical and physical properties? a. carbon, nitrogen, and oxygen b. sodium, potassium, and rubidium c. boron, silicon, and germanium d. sodium, magnesium, and aluminum e oxygen, sulfur, and chlorine 14. a· The solubility ofNaCl in hot water is greater than the solubility in cold water. b. The electrical conductivity of aluminum is greater than copper. c· The density of copper is less than the density of lead. d. The boiling point of water is greater than the boiling point of ethanol. e. Potassium reacts with water more quickly than calcium reacts with water 15. Which one of the following statements is not a comparison of physical properties? What is the correct formula for ammonium bromide? a. NH4Br2 16. b. NH Br c. NHLBr d. (NH4hBr e. NH2Br

Explanation / Answer

Q12

in metric system, we use the METER, m

Q13

physcal changes = will not change the chemical composition of species

1 - density is physcal change

2 - aluminium melting point is physical change

3- decomposition of H2O2 to H2 and O2 is chemical change

choopse 1 and 2

"D"

Q14

elements of the same GROUP (vertical lines) will have simlar properties

a) false, this is a row

b) true, this is a metal group

c) flase, this is metalloids

d) false, these are rows

e) false, this is a row

Q15

a. this is physcal property

b. this is physcal property

c.-  this is physcal property

d.  this is physcal property

e. this is chemical, since it states "reacts" which is the main verb of a reaction

Q16

ammonium = NH4+

bromide = Br-

then NH4Br is correct, choose C

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