What is matter?
Anything that has mass and takes up space.
What is the difference between an element
compound
What is the difference between homogeneous and heterogeneous mixtures?
Homogeneous = uniform composition throughout (salt water)
What are physical changes?
Changes that don’t alter identity (melting
What are chemical changes?
Changes that create a new substance (rusting
What is the difference between accuracy and precision?
Accuracy = closeness to true value
What are significant figures used for?
To communicate precision in measurements.
How do you determine the number of sig figs in a measurement?
All nonzero digits are significant
How do you add/subtract with sig figs?
Answer has same number of decimal places as the least precise number.
How do you multiply/divide with sig figs?
Answer has same number of sig figs as the least precise number.
What is scientific notation?
A way to express very large or small numbers using powers of 10.
Convert 0.000321 to scientific notation.
3.21 × 10⁻⁴.
Convert 6.12 × 10³ to standard form.
6120
What is density?
Mass ÷ volume.
What are the units for density?
g/mL or g/cm³.
If a block has a mass of 250 g and a volume of 50.0 mL
what is its density?
What is an atom?
The smallest unit of an element that still retains the element’s properties.
What are the three subatomic particles and their charges?
Proton (+1)
Where are the subatomic particles located?
Protons and neutrons = nucleus
What is the atomic number?
The number of protons in an atom.
What is the mass number?
Protons + neutrons.
How do you find the number of neutrons in an atom?
Mass number – atomic number.
What is an isotope?
Atoms of the same element with different numbers of neutrons (different mass number).
What is the average atomic mass on the periodic table?
A weighted average of all naturally occurring isotopes.
