chemistry 3rd exams

What best defines matter?,

Something that occupies space and has mass

What property of water is shown when poured into different containers?

,Water has no fixed shape

What remains constant when a substance is divided?,

Density of the substance

Best first step to separate sand from saltwater?

,Filtration

What indicates a homogeneous mixture?,

The mixture looks uniform throughout

What happens to density when a metal cube is cut in half?,

Density stays the same

Why does the smell of cooking spread?,

Matter particles are constantly moving

Why do dyes travel different distances in chromatography?,

Different interactions with paper and solvent

Why is density useful for identifying substances?,

Density is constant for pure substances

Same volume but different mass means what?,

Different densities

Evidence that a substance is pure?,

Cannot be separated physically

Is density a chemical property?

,No, it is a physical property

Correct scientific notation? A. 45 × 102 B. 0.67 × 103 C. 6.7 × 102 D. 670 × 10−1

,6.7 × 10²

How many significant figures are in 0.05060?,

Four

SI unit for density?,

Kilograms per cubic meter

Volume of 4.0 × 2.5 × 3.0 cm block?

,30 cm³

Most accurate tool for liquid volume?

,Graduated cylinder

Balance reads consistently high—what error?,

Systematic error

12.346 cm recorded with 0.1 cm ruler—issue?

,Too many digits

Why does one object sink and another float?

,Different densities

10 miles in kilometers?,

16.0 km

Why is 7.856 rounded to 7.86?,

Significant figure rules

Object density 0.85 g/mL—what happens?,

Floats in water

3.2 × 10⁴ m equals?,

32 km

Mass of 3 electrons and 2 protons?

,3.35 × 10⁻²⁷ kg

Who proposed indivisible particles?

,Democritus

Key idea of Dalton's atomic theory?,

Atoms are indivisible

What defines an element?

,Number of protons

Why plum pudding model?

,Electrons embedded in positive matter

13 protons and 14 neutrons—mass number?

,27

Atomic number 9 mass 19—neutrons?

,10

What are isotopes?

,Same protons different neutrons

Why isotopes act chemically similar?

,Same electron arrangement

Law explaining whole-number ratios?

,Law of multiple proportions

CO and CO₂ demonstrate?

,Law of multiple proportions

Which particle adds least mass?,

Electron

Plum pudding model description?

,Electrons spread in positive charge

Why do atoms bond?

,To achieve stable electrons

How is deuterium different from hydrogen?

,It has one neutron

What affects isotope density most?

,Number of neutrons

Metal rod cut in half—what properties change?,

Mass and volume change (extensive); density stays the same (intensive)

How do you separate sand salt and water?,

Filtration removes sand; evaporation or distillation separates salt and water

How can consumers prevent dangerous bleach reactions?,

Never mix bleach with acids or ammonia to avoid toxic gases

How do isotopes of hydrogen differ?,

They have different numbers of neutrons but the same number of protons

Why do hydrogen isotopes have the same chemical properties?,

They have the same electron arrangement

Protons electrons and neutrons in protium?,

1 proton 1 electron 0 neutrons

Protons electrons and neutrons in deuterium?,

1 proton 1 electron 1 neutron

Protons electrons and neutrons in tritium?

,1 proton 1 electron 2 neutrons

Protons electrons and neutrons in carbon-12?,

6 protons 6 electrons 6 neutrons

Why does one object float and another sink if they are the same size?,

Objects with density less than water float while higher density objects sink

Relationship between mass volume and density?

,Density equals mass divided by volume

What is specific gravity?

,Ratio of a substance's density to the density of water

How do you calculate specific gravity?,

Density of substance divided by density of water

anything that has mass and takes up space.

It can exist in different states, such as solid, liquid, or

gas, and can be composed of various elements and

compounds.

Matter →

Anything that has mass and takes up space.

States of Matter →

Different physical forms of matter such as solid, liquid, gas, plasma, and Bose-Einstein Condensate.

Particles of Matter →

Tiny building blocks (atoms and molecules) that make up all substances.

Solid →

State of matter with definite shape and volume; particles are tightly packed and vibrate in place.

Liquid →

State of matter with definite volume but no definite shape; particles are close together and can slide past each other.

Gas →

State of matter with no definite shape or volume; particles are far apart and move freely.

Plasma →

Fourth state of matter made of positively and negatively charged particles; found in stars, lightning, and neon lights.

Bose-Einstein Condensate (BEC) →

Fifth state of matter formed at temperatures near absolute zero where particles move as one unit.

Thales of Miletus →

Proposed that water is the fundamental substance of all matter.

Significance of Thales →

First attempt to explain nature using a single element.

Empedocles →

Proposed that all matter is made of four elements: earth, air, fire, and water.

Signi