Exam 1 Flashcards
Are pure substances visible to our naked eye?
No, we talk about it at the submicroscopic level
Are Mixtures visible to our naked eye?
Yes, we talk about it at the microscopic level
What are the two types of pure substances?
Elements and Compounds
What are the two types of mixtures?
Heterogeneous or Homogeneous
What is the difference between an elements and a compound?
An Element is a singular composition of matter (elements form the periodic table)
A compound is made up of these elements
What is the difference between a homogeneous and heterogeneous mixture?
Homogeneous is a mixture that has a uniform appearance.
EX: salt and sugar
Heterogeneous is a mixture that has a visible variety of substances
EX: salt and pepper
What are the types of properties?
Physical and chemical
What is part of a physical property?
it can include appearance, density, solubility, freezing point, boiling point
How do we know a property is physical?
Physical properties do NOT change the identity of the substance
What is part of a chemical property?
Flammability and Reactivity
What determines a property as a chemical one?
Chemical changes convert one substance into another
What type of measurement system do we use in science?
The Metric System
In sig figs ________ always count
Integers
Do zeros in between 2 integers count? Provide an example
Yes, zeros in between two integers ALWAYS count
ex: 12,004
Do zeros in the beginning of a number count? Provide an example..
No, zeros in the beginning of a number NEVER count
ex: 0.000015
Zeros at the end only count if and only if…
there is a decimal
ex: 1,200.56
What do we know about zeros that are at the end but before a decimal?
We are unsure of whether or not they count
ex: 100
When calculating sig. figs, (addition and subtraction), what are the rules?
Your final answer can only have as many decimal places as the least exact measurement.
ex: 3.18 + 0.01315 means your answer can only have 6 decimal places since 0.01315 is the LEAST exact measurement
When calculating sig. figs, (multiplication and division), what are the rules?
Your final answer can only have as many SIG FIGS as the least exact measurement.
ex: 203 * 0.0048 means your answer can only have 2 sig figs since 0.0048 has the LEAST exact measurement.
What contents are in scientific notation?
It contains a coefficient and an exponential notation (*10 ^ x)
If the exponent in the notation is positive, where do we move the decimal?
to the right
If the exponent in the notation is negative, where do we move the decimal?
To the left
What are the 3 conversion factors for grams?
1 kg = 1000 g
1mg = 0.001 g
1000 mg = 1 g
How do you convert from Celsius to Kelvin?
K= Celsius + 273
How do you convert Kelvin to Celsius
Celsius= K - 273
How do you convert Farenheit to Kelvin?
- Convert Farenheit to Celsius
Celsius = (F - 32) * (5/9) - Use the celsius to convert to Kelvin
Celsius +273
How do you convert Kelvin to Farenheit?
- Convert Kelvin to Celsius by subtracting 273
- Use that value to find farenheit
Celsius * (9/5) + 32
What is the formula for specific heat?
heat / (mass) ( change in temp)
OR
(J)/ (g * Change in Celsius)
What is the notation (from class) to write an atom
includes mass # and atomic #
[ mass #]
[ Atomic # } X
What is an isotope?
These occur when atoms of the same element contain different numbers of neutrons
What is an ion?
An ion is formed when an atom (or groups of atoms) has either a +/- charge due to their number of electrons
If we have too many electrons we have a/an _______. It has a __________ charge
Anion/ negative
If we have too few electrons, we have a/an _________. It has a ___________ charge
Cation/ positive
Which periodic group is more likely to lose electrons?
Metals/non metals/ halogens/ noble gases
metals
Which periodic groups is more likely to gain electrons?
Non metals
How do you solve for atomic mass?
First separate the isotopes with their corresponding percentage. Then multiply their individual mass with their percent. Lastly, add the two values in order to get your average atomic mass.
How do you solve for mass percent?
You simply divide the mass of the element by the total mass and then multiply by 100
What is Daltons Atomic Theory
- All matter is made from indivisible particles called atoms
- Atoms of the same element are chemically identical
- Elements are characterized by the mass of their atoms
- Atoms join in small whole number ratios to form compounds
- Reactions change the combination of atoms not the atoms themselves
How is Dalton’s Atomic Theory a bit outdated?
Although atoms are indivisible particles, we know that something makes up those atoms (protons, neutrons and electrons)
We also know that atoms of the same element can have different masses due to their number of neutrons
All types of light and radiations fall along the ___________ spectrum
electromagnetic
What is the order of lowest energy to highest?
Radio waves, microwaves, Infarred, Ultraviolet, X Rays and Gamma Rays
Particles of light are called
Photons
How dies Atomic Spectra help our understanding of electron energy.
This helps us understand that electron energy is quantized. The specific colors associated with atoms is due to the amount of energy level.
What do we mean by quantized?
This means there is only a specific amount of energy allowed for every electron
t/f Electrons follow definite circular paths
false, they are mainly in a diffused cloud of negative charge around the nucleus
t/f atomic orbitals are NOT solids
true, orbitals are simply areas in which an electron will most likely be located