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WorksheetsMidterm Chem
Total questions: 20
Worksheet time: 10mins
Lighting a match and baking a cake are two activities that involve chemical changes. Why are these actions considered chemical changes?
They change the state of matter.
They create new substances.
They change volume.
They create energy.
Which equation for the complete combustion of propane (C3H8) is correctly balanced?
C3H8 + 3O2 --> 2 CO2 + 4H2
C3H8 + 7O2 --> 3CO2 + 4H2O
2C3H8 + 10O2 --> 6CO2 + 8H2O
C3H8 + 5 O2 --> 3CO2 + 4H2O
What type of reaction is shown below?
2KClO3 --> 2KCl + 3O2
synthesis
combustion
decomposition
single replacement
A sodium (Na) atom contains 11 protons, 12 neutrons, and 11 electrons. In order to make the sodium ion Na+, what must happen to the sodium atom?
It must gain one electron.
It must lose one electron.
It must gain one proton.
It must lose one proton.
Neutrons are particles of an atom that
Are part of the nucleus.
Are located outside the nucleus.
Have positive charges.
Have negative charges.
What do the ions K+, Ca2+, and Cl- have in common?
They have the same number of protons
They are all metals
They have the same electron configuration as Argon
They are larger than their original atoms
A student has a homework assignment to identify the properties of an element based on its electron configuration. If the element has an electron configuration of 1s22s22p63s23p64s23d104p5, which of the following is most likely a property of this element?
Low ionization energy
Form ions with a -2 charge
Good electricity conductor
Has 7 valence electrons
In the electron cloud model of the atom, what does the cloud represent?
The exact orbits of the electron
The probability of the electron location
The average distance between the electron and the nucleus
The minimum distance between the electron and the nucleus
Which of the following electron movements will release visible light?
n = 4 to n = 2
n = 2 to n = 1
n = 1 to n = 2
n = 1 to n = 3
Copper is used in electrical wiring because electrons are
Shared between two atoms.
Transferred between atoms forming ions.
Delocalized and can move between many atoms.
Held very tightly by each atom.
A bond is formed when an electron is transferred from a sodium atom to a chlorine atom. What happens to the sodium atom during this process?
The mass of the atom increases.
The atom becomes an isotope.
The atomic number decreases.
The atom becomes a positive ion.
Which is true about the melting points of ionic and molecular compounds?
The melting points of ionic and molecular compounds are similar.
The melting points of ionic compounds are lower than the melting points of molecular compounds.
The melting points of ionic and molecular compounds increase with the number of atoms present in the compound.
The melting points of ionic compounds are higher than the melting points of molecular compounds.
What is the chemical formula of magnesium fluoride?
MgF
MgF2
MgF3
Mg2F2
What is the correct name for the compound whose formula is Fe2O3?
Iron oxide
Iron trioxide
Iron (II) oxide
Iron (III) oxide
What is the IUPAC name of the compound whose formula is (NH4)3(PO4)?
Ammonium phosphate
Triammonium monophosphate
Triammonium phosphate
Ammonium phosphide
Which substance, when mixed with water, will produce the best conductor of electricity?
Table salt (NaCl)
Glucose (C6H12O6)
Carbon dioxide (CO2)
Bromine (Br2)
Chromium is characterized by a very high melting point. Use the Periodic Table to identify which of these elements most likely has a similar melting point.
Chlorine
Manganese
Bromine
Krypton
Electronegativity is a measure of how easy it is for an atom to attract another electron. The elements He, Ne and Ar have the lowest electronegativity values. What do these elements have in common?
They have an outer orbital full of electrons.
They have one electron in their outer orbital.
They lose a proton which makes them negatively charged.
They have an extra electron which makes them positively charged.
What remains after 20984Po undergoes alpha decay?
20985Po
20984Po
20582Po
20582Pb
When a gamma ray is emitted by an element, what happens to the atomic mass and the atomic number?
The atomic mass stays the same, and the atomic number stays the same.
The atomic mass changes, and the atomic number stays the same.
The atomic mass stays the same, and the atomic number changes.
The atomic mass changes, and the atomic number changes.
