Question

1. a sample of wood with a mass of 3.0 grams was burned in an open dish. the ashes weighed 1.2 grams. what happened to the rest of the wood?

a) nothing, the burned wood simply has a mass of 1.2 grams.
b) the remaining 1.8 grams was converted into gaseous compounds.
c) the remaining 1.8 grams was converted into heat.
d) the remaining mass was destroyed.
e) none of the above

1. which of the statements below is not part of the scientific method?

a) testing of a hypothesis by experimentation
b) observation and measurement
c) formation of a hypothesis
d) refinement of a hypothesis as needed
e) all of the above steps are part of the scientific method.

1. who discovered the law of conservation of mass?

a) john dalton and antoine lavoisier
b) nivaldo tro
c) antoine lavoisier
d) john dalton
e) none of the above
true/false. write t if the statement is true and f if the statement is false.

1. the number 0.010100 has five significant figures.
2. when the number 2.35 is rounded to contain 2 significant figures it becomes 2.4.
3. the decimal number 0.0000010 expressed in scientific notation is 1.0 x 10^6.

multiple choice. choose the one alternative that best completes the statement or answers the question.

1. the correct prefix for the multiplier 1,000 is:

a) milli.
b) micro.
c) nano.
d) mega.
e) none of the above

1. determine the answer to the following equation with correct number of significant figures: (17.103 + 2.03) x 1.02521 =

a) 19.62
b) 19.6
c) 20
d) 19.6153
e) none of the above

Explanation:

1. According to the law of conservation of mass, mass is neither created nor destroyed in a chemical reaction. When wood burns, the un - accounted mass is converted into gaseous compounds. Heat is a form of energy, not mass.
2. The scientific method involves observation, hypothesis - formation, experimentation to test the hypothesis, and refinement of the hypothesis as needed. All the given steps are part of it.
3. Antoine Lavoisier discovered the law of conservation of mass.
4. Non - zero digits and zeros between non - zero digits are significant. Trailing zeros after a decimal point are significant. So 0.010100 has five significant figures.
5. When rounding 2.35 to 2 significant figures, since 5 is followed by no digit or a zero, we round up. So it becomes 2.4.
6. 0.0000010 in scientific notation is \(1.0\times10^{- 6}\), not \(1.0\times10^{6}\).
7. The prefix for 1000 is kilo. None of the given options are correct.
8. First, add 17.103 and 2.03: \(17.103 + 2.03=19.133\). Then multiply by 1.02521: \(19.133\times1.02521 = 19.6153\). The least number of significant figures in the values being multiplied/addition is 3 (2.03 has 3 significant figures). Rounding 19.6153 to 3 significant figures gives 19.6.

Answer:

1. B
2. E
3. C
4. T
5. T
6. F
7. E
8. B