unit 1

Question 1

what are intensive properties?

Answer 1

they do not depend on the amount of matter that is present - boiling point, color, temperature, luster, hardness.

Question 2

what are extensive properties?

Answer 2

do depend on the amount of matter that is present. an extensive property is considered additive for subsystems - volume, mass, weight, size, length.

Question 3

what is a physical change?

Answer 3

a change that affects the form of a substance, but not it’s chemical composition.

Question 4

what is a chemical change?

Answer 4

a change that affects the chemical composition of a material - for example baking a cake.

Question 5

what is dalton’s atomic theory?

Answer 5

elements are made up of tiny particles called atoms, which are tiny unbreakable spheres.

Question 6

law of definite proportions?

Answer 6

different samples of the same compound always contain their constituent elements in the same proportion by mass.

Question 7

law of multiple proportions?

Answer 7

elements can combine in different ways to form different chemical compounds, whose mass ratios are simple whole-number multiples of each other.

Question 8

law of conservation of mass?

Answer 8

in a chemical reaction, mass is neither created nor destroyed. for example if a piece of wood burns the ash and excess is the same mass as the solid wood.

Question 9

what is an isotope?

Answer 9

elements that contain equal numbers of protons but different numbers of neutrons.

Question 10

what is a molecule?

Answer 10

an aggerate of at least two atoms in a definite arrangement held together by chemical forces.

Question 11

what are the diatomic molecules?

Answer 11

nitrogen, oxygen, fluorine, chlorine, bromine, iodine, astitine.

Question 12

what is the molecular formula?

Answer 12

shows the exact number of atoms of each element in the smallest unit of the substance.

Question 13

what is the structural formula?

Answer 13

shows how the atoms are bonded to each other in a molecule.

Question 14

what is the empirical formula?

Answer 14

tells which elements are present and the simplest whole-number ratio of their atoms.

Question 15

electrically neutral?

Answer 15

cations and anions are combined so the net charge is zero.

Question 16

name the prefix for nonmetals 1-10?

Answer 16

mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca

Question 17

what is avogadro’s number?

Answer 17

6.022e23

Question 18

percentage composition?

Answer 18

percent by mass of each element in a compound or molecule.

Question 19

what is an electrolyte?

Answer 19

a substance that when dissolved in water results in a solution that can conduct electricity.

Question 20

what is a non-electrolyte?

Answer 20

a substance that does not readily ionize when dissolved or melted.

Question 21

strong electrolytes?

Answer 21

soluble ionic compounds -    HCl, HBr, HI 
HClO4
HNO3
H2SO4, KBr
NaCl, NaOH, KOH

Question 22

weak electrolytes?

Answer 22

CH3CO2H
HF
HNO2
NH3

Question 23

non-electrolytes?

Answer 23

H2O, C6H12O6
CH3OH, C2H5OH
C12H22O11
most of organic compounds.

Question 24

what is a solution?

Answer 24

a homogenous mixture of two or more substances in relative amounts that can be varied continuously up to what is called the limit of solubility.

Question 25

what is a solvent?

Answer 25

the substance in which a solute dissolves to produce a homogeneous mixture.

Question 26

what is a solute?

Answer 26

a substance that is dissolved in a solution is called a solute.

Question 27

what is molarity?

Answer 27

a way to express concentration.

Question 28

what is dilution?

Answer 28

the procedure for preparing a less concentrated solution from a more concentrated solution.

Question 29

how to find a dilution?

Answer 29

M1V1 = M2V2