Introduction to Chemistry
Organized process used by scientists to verify the work of others
The Scientific method
What is mass?
The amount of matter in a substance, particle or object
What is a mixture?
The combination of two or more pure substances
What is an element?
Is a pure substance that can't be separated into simpler substances by physical or chemical means.
What is a gas?
A substance or matter in a state in which it will expand freely to fill the whole of a container, having no fixed shape and no fixed volume.
What is chemistry?
The study of matter and the changes that it undergoes.
The change of state from gas to solid, without passing through the liquid state
Deposition or crystallization
Define heterogeneous mixture:
A mixture in which the individual substances remain distinct
Mention 5 examples of elements
Any element from the periodic table is an example.
The Gas laws explain the relationship between:
Pressure, volume and Temperature.
List the steps of the scientific method in correct order (according to the book):
1. Observation
2. Hypothesis
3. Experiment
4. Conclusions
5. Theory
6. Revised theory
7. Scientific law or scientific theory
Mention 2 examples of physical changes:
When objects or substances undergo a change that does not change their chemical composition
What is a solution?
AKA homogenous mixture, it has a single phase and constant composition
What is a compound?
Is made up of 2 or more different elements that are chemically combined.
"The volume of a given amount of gas is directly proportional to its Kelvin temperature at constant pressure"
Charles's Law
Mention 5 branches of chemistry:
Organic chemistry
Inorganic chemistry
Biochemistry
Environmental chemistry
Analytical chemistry
Industrial chemistry
Polymer chemistry
Theoretical chemistry
Mention 3 examples of chemical changes:
Happens when one chemical substance is transformed into one or more different substances
What is filtration? For what type of substance would you use it?
Filtration is a technique that uses a porous barrier to separate a liquid from a solid.
Mention 3 examples of compounds:
Any molecule formed by 2 or more elements is an example of compound.
Using the data below, find the V2:
V1= 0.75L
P1= 2.25atm
P2= 1.03atm
P1V1=P2V2
Answer:
1.6L
Mention 1 example of qualitative data and 1 example of quantitative data:
1. Qualitative: Describes physical characteristics
2. Quantitative: Numerical information
What is the difference between extensive and intensive properties of matter? Mention 1 example of each one.
An intensive property does not depend on the amount of substance but extensive does.
What is distilation? For whay type of mixtures would you use it?
It's used with liquid-liquid solutions.
Distilation is a physical separation technique that is based on differences in the boiling points of the substances involved.
Calculate the percet by mass of N, H and O in the following compound:
Compound NOH3 has a total mass of 133g: 25g of Nitrogen and 76g of Hydrogen.
Total mass: 133g
N: 25g, H: 76g, O: 32g
N: 18.7% H: 57.1% O: 24%
"The pressure of a fixed amount of gas varies directly with Kelvin temperature when volume remains constant"