Unit 1: introduction to matter and measurement

what steps do we use in science

1. Make observations

2. Pose a problem/ask a question

3. Form a hypothesis

4. Conduct an experiment

5. Analyze and record data

6. Draw conclusions

what types of data exist and how do we measure it?

quantitative is numbers and qualitative is details and descriptions

how do the chemical and physical properties of matter affect life?

they are essential for life, enabling everything from the formation of living cells to basic biological processes like digestion and breathing.

how do matter and energy relate?

where a small amount of mass is equivalent to a vast amount of energy. Matter is made of particles and energy is a property of these particles and their interactions, influencing their movement and arrangement

Why does matter change

Primarily due to the addition or removal of energy, usually in the form of heat which affects the motion and arrangement of its particles (atoms and molecules

Identify the metric units of measurement for mass

Kilogram

Identify the metric units of measurement for volume

liter, milliliter, or cubic meter (m³)

Identify the metric units of measurement for density

(kg/m³) or (g/mL)

explain the difference between accuracy and precision

accuracy is a measure of how close a measurement is to the correct or accepted value of the quantity being measured. Precision is a measure of how close a series of measurements are to one another.

Describe the difference between physical and chemical changes

during a physical change, molecules stay the same, but the state may change. However, during a chemical change, an entire new material is created or the atoms become rearranged

explain the difference between an element and a compound

an element is a pure substance made of only one type of atom, while a compound is made of two or more different atoms chemically bonded in a fixed ratio

explain why compounds are considered pure substances

they always consist of the same elements chemically bonded in a fixed ratio, giving them a constant composition and properties

compare and contrast heterogeneous and homogeneous mixtures

homogenous mixtures are uniform throughout, appearing as a single phase with evenly distributed components that cannot be seen with the naked eye (e.g. saltwater) while heterogeneous mixtures are non-uniform, containing visibly distinguishable components or phases that vary in composition.

list several techniques used to separate mixtures

chromatography, distillation, evaporation, filtration

Chromatography

involves solvent separation a solid medium

distillation

takes advantage of differences in boiling point

evaporation

removes a liquid from a solution to leave a solid material

filtration

separates particles of different sizes

1 kilo =

1000 g/m/L

1 g/m/L =

100 centi ( c )

1 g/m/L

1000 milli (m)

Chemistry

the study of the composition of matter and the changes that matter undergoes

international system of units (SI)

is a system of measurement based on the metric system. There are 7 basic units in SI system, 5 of these units are commonly used in chemistry

mass

measure of the amount of matter in a substance or object

Volume

measure of the amount of space that a substance or an object takes up

precision

is a measure of how close a series of measurements are to one another

accuracy

is a measure of how close a measurement is to the correct or accepted value of the quantity being measured.

Matter

is anything that has mass and takes up space. Everything that you can see and touch.

Liquid

have definite volume, but take the shape of the container

physical property

can be measured without changing the identity or chemical composition of a substance

Physical change

is a change to a sample of matter in which some properties of the material change, but the identity of the matter does not. Molecules stay the same, state may change.

Element

simplest form of matter that has a unique set of properties

compound

is a substance that contains two or more elements chemically combined in a fixed proportion

mixture

combination of two or more substances in any proportion

Phase

is any part of a sample that has a uniform composition and properties

metric system

all metric units are based on the multiples of 10, making conversions very simple

base unit

fundamental unit in a system of measurement this is what derived units are built from

derived unit (ex: g/mL)

the unit that results from a mathematical combination of SI base units

metric prefix

used to distinguish between units of different sizes

centi

1/100

milli

1/1000

kilo

1000

accepted/theoretical value

the true or correct value of a measurement based on general agreement with a reliable reference

experimental/actual value

the quantitative value of a measurement obtained during an experiment

Significant digit (sig figs)

in a measurement consist of all the certain digits in that measurement plus one uncertain or estimate digit

solid

have definite shape and volume

gas

have no definite shape or volume

chemical property

describes the ability of a substance to undergo a specific chemical change

chemical change

produces different materials than the ones we started with; also called a chemical reaction

pure substance

is matter that has uniform and definite composition. Have identical properties and cannot be separated into components by physical separation techniques

heterogeneous mixture

a mixture in which the composition is not uniform throughout the mixture; example;trail mix

homogenous mixture

a mixture in which the composition is uniform throughout the mixture; example: salt water. All solutions would be considered homogenous. Consist of one phase.

When would you use this separation technique: removal w/forceps

separate materials according to substance properties like particle size: this an example of mechanical removal

When would you use this separation technique: magnetism

using a magnet to attract and remove the magnetic particles, leaving the non-magnetic materials behind

What are the parts of the scientific process

a. Hypothesis, theory and law

b. Independent and dependent variables

c. Qualitative and quantitative

hypothesis

prediction, experiment

theory

Explanation of facts and large body of evidence

law

fact of science

independent variable

manipulated/changed; x-axis

dependent variable

affected by change; y-axis

qualitative observations

color, odor, etc

quantitative observations

Numerical/measured

distinguish between two major types of matter: mixtures and pure substances

mixtures have 2+ elements and/or compounds; not fixed proportions; separated by physical means. pure substances are elements/compounds cannot be separated by physical means.

Distinguish between the two types of pure substances

elements: same atoms, cannot be chemically/electrically separated ex: Ne, H2. compound: 2+ different atoms can be chemically/electrically separated ex: H2O, NaCl

Elements vs. compounds - which one could you chemically separate?

compounds, can only be decomposed by heat and electricity only

distinguish between the two types of mixtures. How can you tell which one you have?

heterogeneous is unevenly distributed like oil and water. homogeneous (also known as solution) - appears uniform throughout with no visible boundaries, such as salt dissolved in water.

How can you separate the two types of mixtures?

can be separated by using simple methods that focus on differences in density or particle size…however homogeneous separation requires more advanced techniques such as evaporation & distillation

true or false: a pure substances is made of two or more elements that are chemically combined is a ___Mixture___

false, compound

An element is a pure substance that cannot be broken down into any other substances by chemical means.

True

During a chemical change, the form of a substance is altered, but not its identity.

false, physical change

Steel rod being heated into a molten metal is an example of a phase change.

true

Ice is an example of the liquid state of matter.

false, solid

Inferences are observations made by using your five senses.

false, observations

A dependent (responding) variable is the factor in an experiment that is purposely changed to test a hypothesis.

false, independent variable

What is the density of water in g/mL

1.0g/mL

Percent error

Shows how accurate and precise your date is. Compares your actual data (the experimental data) to the theoretical (accepted or theoretical) data obtained from a scientist

Percent error formula

l Accepted (theoretical) value - experimental value/ accepted value l x 100

How can you find density?

m/v

How can you calculate mass?

D x V

How can you calculate volume?

M/D