Final Exam A

Question 1

What are significant figures in measurement?

Answer 1

All the known digits plus the last estimated digit.

Significant figures are important in scientific measurements to convey precision.

Question 2

What is the rule for significant figures regarding non-zero digits?

Answer 2

All non-zero digits are significant.

Example: 2,456 has 4 significant figures.

Question 3

What is the rule for significant figures regarding leading zeros?

Answer 3

Zeros in front of the number are not significant.

Example: 0202 has 3 significant figures.

Question 4

What is the rule for significant figures regarding zeros between non-zero digits?

Answer 4

Zeros between non-zero digits are significant.

Example: 3,004 has 4 significant figures.

Question 5

When are trailing zeros significant in a number?

Answer 5

Trailing zeros are significant if there is a decimal point in the number.

Example: 200 has 1 significant figure, while 0.046700 has 5 significant figures.

Question 6

How should you round your answer in addition and subtraction operations involving significant figures?

Answer 6

Round your answer to the decimal place of the measurement with the least amount of significant figures.

Question 7

How should you round your answer in multiplication and division operations involving significant figures?

Answer 7

Round your answer to the same number of significant figures as the measurement with the least amount of significant figures.

Question 8

Define accuracy in measurements.

Answer 8

A measure of how close a measurement comes to the actual or true value.

Question 9

Define precision in measurements.

Answer 9

A measure of how close a series of measurements are to one another.

Question 10

What is an element?

Answer 10

The simplest form of matter that has unique properties, denoted by a chemical symbol.

Examples include H (Hydrogen), Fe (Iron), Ne (Neon).

Question 11

What is a compound?

Answer 11

Two or more elements chemically combined, with different properties than the elements they are made of.

Question 12

What is a mixture?

Answer 12

A physical blend of two or more components.

Examples include soup and salad.

Question 13

What is a heterogeneous mixture?

Answer 13

A mixture in which the composition is not uniform throughout.

Examples include cookies and salads.

Question 14

What is a homogeneous mixture?

Answer 14

A mixture with uniform composition, also known as a solution, which can only have 1 phase.

Examples include saltwater and vinegar.

Question 15

What is a solute?

Answer 15

What gets dissolved in a solution.

Question 16

What is a solvent?

Answer 16

What does the dissolving in a solution.

Question 17

How are compounds separated?

Answer 17

Only by chemical means, such as heating or electricity.

Question 18

How are mixtures separated?

Answer 18

Physically, using techniques like filtration, distillation, or chromatography.

Question 19

Define extensive properties.

Answer 19

Properties that depend on the amount of matter in a sample.

Examples include mass and volume.

Question 20

Define intensive properties.

Answer 20

Properties that depend on the type of matter, not the amount.

Examples include density and color.

Question 21

What is a physical property?

Answer 21

A quality or condition that can be observed or measured without changing the substance’s composition.

Question 22

What is a chemical property?

Answer 22

The ability of a substance to undergo specific chemical changes.

Question 23

What is a physical change?

Answer 23

Some properties change, but not the chemical composition.

Question 24

What is a chemical change?

Answer 24

The chemical composition of the substance changes.

Question 25

What are the states of matter?

Answer 25

Solid, Liquid, Gas.

Question 26

What is the phase change from solid to liquid called?

Answer 26

Melting.

Question 27

What is the phase change from liquid to gas called?

Answer 27

Evaporation.

Question 28

What is the phase change from gas to liquid called?

Answer 28

Condensation.

Question 29

What is the phase change from liquid to solid called?

Answer 29

Freezing.

Question 30

What is the phase change from solid to gas called?

Answer 30

Sublimation.

Question 31

What is the phase change from gas to solid called?

Answer 31

Deposition.

Question 32

What are the parts of an atom?

Answer 32

Protons, Neutrons, Electrons.

Question 33

What is the charge and location of protons?

Answer 33

Positive charge, located inside the nucleus.

Question 34

What is the charge and location of neutrons?

Answer 34

Neutral charge, located inside the nucleus.

Question 35

What is the charge and location of electrons?

Answer 35

Negative charge, located outside of the nucleus.

Question 36

How do you find the atomic number?

Answer 36

It is equal to the number of protons.

Question 37

How do you calculate mass number?

Answer 37

Mass number = protons + neutrons.

Question 38

What is a cation?

Answer 38

A positively charged ion.

Question 39

What is an anion?

Answer 39

A negatively charged ion.

Question 40

What is an isotope?

Answer 40

An atom with the same number of protons but a different number of neutrons.

Question 41

What is nuclear fission?

Answer 41

When the nuclei of certain isotopes are bombarded with neutrons and split into smaller atoms.

Question 42

What is nuclear fusion?

Answer 42

When nuclei combine to produce a nucleus of greater mass.

Question 43

What is radioactive decay?

Answer 43

The process by which unstable nuclei lose energy by emitting radiation.

Question 44

What is an alpha particle?

Answer 44

2 protons + 2 neutrons, represented as 4/2He.

Question 45

What happens to the atomic number during alpha decay?

Answer 45

It drops by 2.

Question 46

What is a beta particle?

Answer 46

An electron formed from a breaking neutron, represented as 0/-1e.

Question 47

What is a gamma ray?

Answer 47

A high energy photon, a form of electromagnetic radiation.

Question 48

What are valence electrons?

Answer 48

The outermost electrons in the highest principal energy level.

Question 49

What does VSEPR theory stand for?

Answer 49

Valence Shell Electron Pair Repulsion theory.

Question 50

What is the molecular geometry for a central atom bonded to two atoms with no lone pairs?

Answer 50

Linear with a 180-degree angle.

Question 51

What is the molecular geometry for a central atom bonded to three atoms?

Answer 51

Trigonal planar with a 120-degree angle.

Question 52

What is the molecular geometry for a central atom bonded to four atoms?

Answer 52

Tetrahedral with a 109.5-degree angle.

Question 53

What is the formal charge formula?

Answer 53

Formal Charge = VE - NE - BE/2.

Question 54

What differentiates ionic and covalent compounds in terms of composition?

Answer 54

Ionic compounds are made of metals and nonmetals, while covalent compounds are made of nonmetals.

Question 55

What is the naming convention for covalent compounds?

Answer 55

Use prefixes to indicate the number of each element and add 'ide' to the end.

Question 56

What is the criss-cross method used for?

Answer 56

To write the formulas for ionic compounds.

Question 57

What is the rule for naming acids that end in '-ide'?

Answer 57

Name starts with 'hydro' and ends with '-ic'.

Question 58

What is percent composition?

Answer 58

Part/whole x 100.

Question 59

How do you determine an empirical formula from percent composition?

Answer 59

Convert % to mass, then to moles, divide by the smallest value, and write out the formula.

Question 60

What does 1 mole equal in terms of particles?

Answer 60

1 mole = 6.02 x 10^23 particles.