Exam One
If an atom has 33 protons, 42 neutrons, and 33 electrons, what is the mass number?
75
Mass number: sum of protons and electrons
Define limiting reactant:
The reactant that can generate the smallest amount of product "limits" the reaction
What is the trend of atomic radii on the periodic table.
-increases from top to bottom because there is an increase in orbitals
-Decreases from left to right
Explain the difference between atomic number and atomic mass.
Atomic Number: # of protons in the nucleus
Atomic Mass: Mass of the atom
Is milk a homogeneous or heterogeneous mixture?
Heterogenous
Milk can be separated at room temperature.
Explain the difference between accuracy and precision.
Accuracy: how close a measured or calculated value is to the true value
Precision: degree to which additional measurements or calculations give the same or similar value.
Equation: P4 + 6 Cl2 → 4 PCl3
What mass of PCl3 is produced from 4.92g of Cl2
1.57g
What is the trend of ionization energy on the periodic table?
-decreases from top to bottom
-increases from left to right
What is the heat of fusion?
energy required when a solid turns into a liquid
True
What is the chemical formula for Calcium Fluoride.
CaF2
What is the equation for percent yield?
actual/theoretical x100
True or False: Light can have mass.
False
Light can behave as a particle but has no mass
Compare the 3 elements: C, O, Si
Place in order of increasing atomic radius.
From smallest to largest: O, C, Si
Electron configurations can predict....
how atoms form molecules
What is the difference between a cation and anion.
Cation: more protons than electrons
Anions: more electrons than protons
Thermodynamics is the study of...
heat (energy) and work
What are the four shapes of atomic orbitals?
s, p, d, f
Describe how an electron emits light.
The electrons move and get excited. This excitement causes electrons to bounce and emit light.
Sublimation: takes energy
Deposition: gives off energy
What are the elements in group 2A on the periodic table.
Alkaline Earth Metals
The temperature of 10.0 g of a piece of copper (C=0.385 J/g K) is raised from 298 K to 598 K, how much heat (q) was required for this temperature change?
q=mcΔT
q=1.16 x 10 ^3 J
Which atom can never be the central atom in a Lewis Dot Structure?
Hydrogen
What is an isotope?
Atoms of the same element with different mass numbers (vary in the # of neutrons)
Mendelev in 1869