Chem Test 1 Flashcards
What are the main branches of chemistry?
- Organic
- Inorganic
- Analytical
- Physical
- Biochemistry
Which branch of chemistry deals with CARBON compounds?
Organic
What is the difference between a homogeneous and a heterogeneous mixture?
Homogeneous mixtures are uniform throughout (e.g., salt water), while heterogeneous mixtures are not uniform (e.g., salad).
How do you classify matter?
Matter can be classified as
- elements
- compounds
- mixtures.
What is the difference between a compound and a homogeneous mixture?
- compound is a pure substance that can only be separated by chemical means,
- homogeneous mixture can be separated by physical means.
What are physical properties?
Physical properties can be observed or measured WITHOUT CHANGING the substance (e.g., density, solubility).
What are chemical properties?
Chemical properties describe a substance’s ability to undergo chemical changes (e.g., flammability).
Name some common lab equipment used for measuring volumes.
Beakers, graduated cylinders
What are some methods used to separate mixtures?
Filtration, distillation, and chromatography.
What is an SDS used for?
An SDS provides safety information about chemicals, including hazards and safe handling instructions.
What safety precautions should be taken when handling chemicals?
Wear goggles, use fume hoods for volatile chemicals, and handle acids with care.
What is the difference between an independent and a dependent variable?
An independent variable is manipulated and placed on the x-axis, while the dependent variable is observed and placed on the y-axis.
What is a direct relationship?
In a direct relationship, as one variable INCREASES, the other also INCREASES.
What is an inverse relationship?
In an inverse relationship, as one variable INCREASES, the other DECREASES.
What is the law of conservation of mass?
In any physical or chemical change, mass is neither created nor destroyed.
What is the difference between a scientific theory and a scientific law?
- theory explains why something happens
- law describes what happens.
What are reactants and products in a chemical reaction?
- Reactants are substances that undergo change
- products are the new substances formed.
What are some aspects of the nature of science?
Science is based on evidence, is subject to change, and involves peer review.
Which branch of chemistry deals with NON-CARBON compounds?
Inorganic
Which branch of chemistry deals with COMPOSITION of samples?
Analytical
Which branch of chemistry deals with the BEHAVIOR/ENERGY of compounds?
Physical
Which branch of chemistry deals with the chemistry of LIFE?
Biochemical
The natural world is _____
Understandable
Science is based on _____
evidence
Scientific ideas are _____ yet subject to _____
- durable
- change
Science is a complex _____ _____
Social endeavor
Scientists try to remain _____ and _____ in peer review to avoid _____
- objective
- engage
- bias
A scientific law is a short _____ statement of ____ happens
- mathematical
- WHAT
A Summary
A scientific law _____ try to explain the relationship it describes
DOES NOT
A scientific law is a _____ _____ for _____ something happens
- Long explanation
- WHY
A theory may need to be _____ at some point in the future to explain new _____ or _____ results
- changed
- observations
- experimental
Theories never become _____
LAWS
We should have only _____ manipulated variable and _____ dependent variable
- one
- one
What does DRY mean for a graph
Dependent variable
Relies on the other
Y-axis
What does MIX mean for a graph
Manipulated Variable
Independent
X-axis
In a direct relationship, y _____ by x equal a _____
So as x is increased, y must _____
- divided
- constant
- increase
in an indirect relationship, x _____ y equals a _____
so as x is increased, y must _____
- times
- constant
- decrease
As the temp of a gas increases, the volume increase. This is a _____ relationshipo
direct
As the volume of a gas decreases, the pressure increases, this is a _____ relationship
indirect
What kind of relationship is this graph
Direct
What kind of relationship is this graph
Indirect
Every experiment should have a _____
Control
What is a control in an experiment
Trial where the manipulated variable is not changed
We should _____ the results of many trials
Average
Results should be _____ by other scientists
reproducible
We should report ____ results, not just the _____ ones
- all
- expected
Chemistry is the study of _____ and its ____
- matter
- change
What is matter
anything that has mass and takes up space
What are the ____ main types of matter
four
What are the 4 main types of matter
- gas
- liquid
- solid
- plasma
We can separate matter in ___ ways?
two
What are the two ways we can separate matter
- physical means
- chemical means
You can separate mixtures by physical means into what?
- pure substances
What are the two types of pure substances
- compounds
- elements
How do you separate pure substances
chemical means
Compounds get separate into elements by what means
chemical
What is the simplest form of matter
element
what are the two types of mixtures
-homogenous
-heterogenous
How may atoms make up an element
1 atom
What is a substance that can be separated only by chemical means into simpler substances
Compound
Compounds can be separated by what means
chemical
How are compounds written
Chemical formula
- H2O
- NaHCO3
What kind of mixtures is composed of only 1 kind of matter
homogenous
Homogenous mixtures are completely _____ throughout
uniform
Homogenous mixtures are also called
solutions
Heterogenous mixtures have a _____ distribution
non-uniform
What mixtures has a non-uniform distribution
heterogenous
What is an example of a homogenous mixture
- salt water
- air
What is an example of a heterogenous mixture
- apple
- salad
What are the 3 kinds of physical means to separate a mixture?
- filtration
- distillation
- chromatography
Separating mixtures by differences in particle sizes is called
filtration
Separating mixtures by differences in boiling point is called
distillation
Separating mixtures by differences in affinity for a substrate is called
chromatography
This picture is an example of what kind of separation?
Physical separation of a homogenous mixtures by distillation
This picture is an example of what kind of separation?
Physical separation of a heterogeneous mixture using magnetism
This picture is an example of what kind of separation?
physical separation a homogeneous mixtures using chromatography
What kind of particle does this picture represent? And why?
Element - cannot be simplified
What kind of particle does this picture represent? And why?
Compound - 2 or more element chemically bonded
What kind of particle does this picture represent? And why?
Element - only 1 type of atom
What kind of particle does this picture represent? And why?
Mixture - can be physically separated
Properties or changes that can be observed and measured without changing the composition of a substance are called?
Physical properties and changes
Changes in form, not substance are called
phyiscal changes
What are 2 examples of a physical change?
- shape change
- size change
What are 3 examples of physical properties
- density
- metallic characteristics (malleability, ductility, luster, conductivity)
- solubility
What is an example of a physical process
conducting heat or electricity
The ability of a substance to undergo a chemical reaction and form a new substance is called what?
chemical property
What are 2 examples of chemical properties
- Flammability/combustibility
- reactivity
Chemical changes are written as _____
reactions
What are 5 indicators that a chemical change may have occured
- ENERGY is absorbed or released (temp changes)
- COLOR changes
- GAS is produced (bubbling, fizzing, odor change, smoke)
- PRECIPITATE is formed - a solid that separates from solution (won’t dissolve)
- IRREVERSIBILITY - not easily undone
Starting substances in a chemical reaction are called _____
reactants
Reactant + Reactant = _____
Product
Name 3 common examples of a chemical change that can be written as a reaction or series of reactions
- rusting
- cooking
- fermenting
What is the law of conservation of mass
in any physical or chemical change, mass is neither created nor destroyed - it is CONSERVED
The mass of the reactants will always ____ the mass of the products. Why?
- equal
- law of conservation of mass
if i react 15g of H2 with 10g of O2 to produce water, how many grams of product will I have?
25 g
how is the nature of science tentative?
people come up with new and different things/info all the time
What is inference
prediction or understanding you make about something
How does one safely dilute an acid?
add acid to water
why are beakers not used to measure specific volumes of liquid?
not specific
What piece of equipment would you use to measure a volume of liquid
graduated cylinder
Is glucose a mixture or pure substance?
Mixture
What is a qualitative observation
describe “qualities” of something - texture, color, shape, and do NOT involve counting or measuring
What is a quantitative observation
involves counting or measuring using standard scales (mass, volume, time, temperature, frequency of occurence, etc)
What are the 5 safety precautions when using a bunsen burner?
- do not reach over a burner
- ensure that flammables are not being used when a burner is lit
- NEVER LEAVE A LIT BURNER UNATTENDED
- know the location of fire extinguishers, the fire blanket, and safety shower.
- when finished, turn off the main gas valve.
What types of information are given about a chemical on an SDS?
- chemical product identification
- composition of ingredients
- hazards identification
- first aid measures
