2nd Semester Science Exam

a mixture in which particles can be seen and easily separated by settling or filtration

Suspension

is a suspension easily mixed?

No

a well-mixed mixture

Solution

how do you separate the particles in a solution?

Boil the water or let the water evaporate

All ___________ have 2 parts.

Solutions

the part of the solution present in the largest amount; dissolves other substances

Solvent

the part of a solution present in the smaller amount; dissolved

solute

what is the "universal solvent

water

How does a solution form?

particles of the solute leave each other and become surrounded by particles of the solvent

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What happens when ionic solids dissolve in water?

Positive and negative ions are attracted to polar water molecules, water surrounds each ion as it leaves the crystal (so the compound breaks apart into its ions).

What happens when molecular solids dissolve in water?

They break into individual neutral molecules but the covalent bonds are not disturbed. The compounds stay together but the molecules separate.

_____________ dissolved in water conduct electricity; ____________ do not.

Ionic compounds, molecular

how much solution is dissolved in a certain amount of solvent

Concentration

a little solute is dissolved

Dilute Solution

Has a lot of solute dissolved

Concentrated Solution

The measure of how well a solute can dissolve in a solvent at a given temperature

Solubility

no more solute will dissolve

Saturated Solution

more solute can be dissolved

Unsaturated Solution

What can be used to determine the identity of a compound?

Solubility

What is solubility affected by?

temperature and the type of solvent

What is the difference in solubility between solids and gasses

typically, more solid can be dissolved in a liquid when temp. rises; but gases are LESS soluble when temp. goes up.

Will a solvent that is polar dissolve a solute that is nonpolar?

no

What dissolve in polar solvents?

Ionic and polar compounds

What does not dissolve in polar solvents?

nonpolar compounds

What do solutes do to solvents?

Lower the freezing point; raise the boiling point

A substance that tastes sour, reacts with metals and carbonates, and turns blue litmus paper red.

acid

which substance tastes sour?

acid

which substance reacts with metals and carbonates?

acid

which substance turns blue litmus paper red

acid

what is an example of an acid?

citrus fruits

Acids react with some ___________ to form __________.

metals, hydrogen

which substances are corrosive?

acid

what happens when acids react with carbonates

produces carbon dioxide

compound that changes color when in contact with acid or base

indicator

what color does blue litmus paper turn in an acid? in a base

red; blue

a substance that tastes bitter, feels slippery, and turns red litmus paper blue?

base

what is the ph of an acid

below 7

what is the ph of a base

above 7

which substance has a bitter taste?

base

which substance is slippery?

base

what color does a base turn red litmus paper?

blue

do bases react with metals or carbonates/

no

do bases react with acids?

yes

what kind of rock is made of calcium carbonate?

limestone

what is a hydrogen ion?

ion found in acids, positive, an atom in hydrogen that has lost an electron

what do acids in water separate into?

hydrogen ions and negative ions

any substance that produces h ions in water can be called what?

acid

what is hydroxide ion?

ion found in bases, negative, oxygen and hydrogen

any substance that produces hydroxide ion in water can be called?

base

what do bases in water separate into

hydroxide ions and positive metal ions

a ______ base produces more hydroxide ions than a ____ base

strong; weak

a ______ acid produces more hydrogen than a _____ acid

strong;weak

range of values from 0 to 14 that expresses the concentration of hydrogen ions in a solution

ph scale

when the ph of a solution is low, the concentration of the hydrogen ions is?

high

a reaction between and acid and base is called?

neutralization reaction

an ionic compound made from the neutralization of an acid and base

salt

what two substances does a neutralization reaction produce

water and a salt

large food pieces turned into small pieces

mechanical digestion

large molecules broken down into simpler smaller molecules

chemical digestion

substances help digestion take place

enzymes

is the ph the same in all parts of the digestive system?

yes

what refers to how well an acid or base produces ions in water?

strength

what is made from the positive ion of a base and the negative ion of an acid

salt

process which breaks complex molecules of foods into smaller molecules

digestion

what enzyme breaks carbohydrates into sugar molecules? where? what ph?

amylase, mouth, near 7

what is the ph of enzyme in stomach

about 2