Question 1

Which of the following statements best describes the difference between a hypothesis and a scientific theory?

Accepted Answer

A hypothesis is a tentative explanation that can be tested, while a scientific theory is a well-substantiated explanation based on a body of evidence.

Question 2

Which of the following is an example of a physical change?

Accepted Answer

Melting of ice into water

Question 3

A sample contains sand, salt, and water. Which of the following best describes this sample?

Accepted Answer

A heterogeneous mixture

Question 4

Which law states that in a chemical reaction, matter is neither created nor destroyed?

Accepted Answer

Law of Conservation of Mass

Question 5

A student measures the mass of a sample three times and gets values that are very close to each other, but far from the true value. This set of measurements is:

Accepted Answer

Precise but not accurate

Question 6

Convert $$25.0 \, ^\circ\mathrm{C} to $$Kelvin.

Accepted Answer

$$298.2 \, \mathrm{K}$$

Question 7

Which experiment provided the first evidence for the existence of the electron?

Accepted Answer

J. J. Thomson's cathode ray tube experiment

Question 8

An isotope of carbon has a mass number of 14 and an atomic number of 6. How many neutrons does it have?

Accepted Answer

$$8$$

Question 9

Which of the following best describes a cation?

Accepted Answer

An atom that has lost one or more electrons

Question 10

Which element is most likely to form a $$2^+$$ ion?

Accepted Answer

Magnesium

Question 11

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have similar chemical properties.

Question 12

How many moles are in $$3.01 	imes 10$$^{23}$$ molecules of water?

Accepted Answer

$$0.500$$ moles

Question 13

Which of the following compounds contains both ionic and covalent bonds?

Accepted Answer

NaNO$$_3$$

Question 14

What is the empirical formula of a compound that is $$40.0\%$$ carbon, $$6.7\%$$ hydrogen, and $$53.3\%$$ oxygen by mass?

Accepted Answer

CH$$_2O$$

Question 15

Which of the following is a correct name for the compound $$\mathrm{FeCl}_3$$?

Accepted Answer

Iron(III) chloride

Question 16

A sample of glucose ($$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6) $$contains $$0.250$$ moles. How many molecules of glucose are present?

Accepted Answer

$$1.51 	imes 10$$^{23}$$

Question 17

Which of the following is a correct statement about the law of definite proportions?

Accepted Answer

A chemical compound always contains the same elements in the same proportion by mass.

Question 18

Which of the following is the correct formula for dinitrogen pentoxide?

Accepted Answer

$$\mathrm{N}_2\mathrm{O}_5$$

Question 19

Which of the following is a property of metals?

Accepted Answer

They are good conductors of electricity.

Question 20

A compound is found to contain $$24.0 g of $$carbon, $$4.0 g of $$hydrogen, and $$32.0 g of $$oxygen. What is the empirical formula of the compound?

Accepted Answer

C$$_2H$_4O$_2$$

General Chemistry I: Study Guide – Matter, Measurement, Atoms, and Compounds

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