Chem 100 Exam 1
The process of fermentation is an example of:
chemical change
What fundamental force is responsible for holding together the subatomic particles of an atomic nucleus?
electromagnetism
Which is lighter electrons or neutrons?
electrons
A human is an example of a(n):
heterogenous mixture
What is the correct IUPAC name for Mg₃(PO₄)₂?
magnesium phosphate
Which is more passive, protons or electrons?
protons
What is electromagnetism responsible for?
the attractions between protons and neutrons in the atomic nucleus
What is the atomic number equal to?
the number of protons in the nucleus
What is the correct molecular geometry of NH₃ according to Valence Shell Electron Pair Repulsion Theory?
trigonal pyramid
Is this correct? Manganese(II) sulfide - MnS
yes
Draw the Lewis structure of ozone (O₃) and then determine its electron domain and molecular geometries.
trigonal planar/bent (120d)
Is this correct?: Potassium phosphate - K₃PO₄
yes
Write the chemical formula for bromine pentachloride:
BrCl₅
Balance the following chemical equation (if necessary) for the combustion reaction of glucose: C(6)H(12)O(6)+O(2) --> CO(2) + H(2)O
C(6)H(12)O(6)+6O(2) --> 6CO(2) + 6H(2)O
Which of the following is a physical change?
a) an alkaline battery is discharged b)a lithium-ion battery is recharged c)water is boiled in a microwave d)a car battery is jump-started e)a pinch of salt is dissolved in water answer: c (the process of boiling water is phase change from liquid to gas)
Gasoline is composed of a variety of different liquid hydrocarbons, which do not separate as time passes. Gasoline is an example of a:
solution (gasoline is a homogenous liquid-liquid mixture of a variety of different hydrocarbons and other soluble additives)
Draw the Lewis structure of CBr₄ and then determine its electron domain and molecular geometries.
tetrahedral/tetrahedral
A more electronegative atom
will have more attraction to the electrons in a chemical bond
Draw the Lewis structure of PF₃ and then determine the number of nonbonding electron pairs on the central atom.
1 nonbonding pair on central atom
What numbers belong in the blank spaces to fully balance the following reaction? __Fe (s) + __Cl₂ (g) → __FeCl₃ (s)
2,3,2
Balance the following chemical equation (if necessary): Ca(s) + O₂(g) → CaO(s)
2Ca(s) + O₂(g) → 2CaO(s)
What is the coefficient in front of the NO when the equation below is balanced? NH₃(g) + O₂ (g) → NO(g) + H₂O (g)
4 (4 NH₃(g) + 5 O₂ (g) → 4 NO(g) + 6 H₂O (g).)
Write the chemical formula for carbon tetrafluoride
CF₄
Write the chemical formula for chromium(III) phosphate:
CrPO₄
Balance the following chemical equation (if necessary) for the combustion reaction of propane:C₃H₈(g) + O₂(g) → CO₂(g) + H₂O(g)
C₃H₈(g) + 5O₂(g) → 3CO₂(g) + 4H₂O(g)
Balance the following chemical equation (if necessary): C₆H₆O(l) + O₂(g) → H₂O(g) + CO₂(g)
C₆H₆O(l) + 7 O₂(g) → 3 H₂O(g) + 6 CO₂(g)
Which one of the following statements best describes electronegativity in atoms?
Electronegativity is the attraction an element's nucleus has for the electrons in a chemical bond.
Which of the following statements about subatomic particles are true? I. Protons and electrons have charges of opposite signs but the same magnitude. II. Protons have twice the mass of neutrons. III. Electrons are lighter than neutrons.
I and III
Which of the following statements about subatomic particles are false? I. Neutrons reside inside of the nucleus. II. The atomic number is equal to the number of neutrons in the nucleus of an atom. III. Electrons are more massive than protons. A) I and II only B) I and III only C) II and III only D) I, II and III
II and III are false
What is a heterogenous mixture?
Mixture with a difference in composition within the mixture
Balance the following chemical equation (if necessary): PbCO₃(s) → PbO(s) + CO₂(g)
PbCO₃(s) → PbO(s) + CO₂(g)
Protons and electrons have charges of __________ signs but the _________ magnitude
Protons and electrons have charges of opposite signs but the same magnitude
Which of these represents a chemical change?
a)lard heated changes to liquid b)water disappears from a beaker in a few days at room temp. c)sugar dissolving in water d)milk turns sour after sitting at room temp. for a few days e)water boils below 100dC on a mt. top answer: milk turning sour (the molecules in sour milk are different than those in fresh and you can't unsour milk)
What is the correct IUPAC name for Cs₃P?
cesium phosphide
What is the correct IUPAC name for Cr₂(SO₄)₃?
chromium (III) sulfate
In the process of making biofuel from corn, the corn is ground, mixed with water, and then enzymes are added to ferment the starch. The fermentation produces ethanol and carbon dioxide. The ethanol is further distilled for use as a biofuel. In this process ______ is an example of a chemical change.
fermenting the starch (starch and sugars are converted ethanol by enzymes)
Italian dressing contains olive oil and vinegar, which will separate out from each other if left to sit. This makes the dressing a:
heterogenous mixture
What kind of mixture is sand?
heterogenous mixture; does not have uniform composition
Is this correct? Copper(I) sulfide - CuS
no, copper (I) sulfide is Cu₂S
A white powder mixture is placed into water. Some of the powder sinks to the bottom of the container, some rises to the top. The separation of the powder mixture is an example of:
physical change (separation of two substances using density is a physical change; no chemical bonds have been made or broken in the process)
The process of filtration is an example of:
physical change (the substances that are being separated do not change into different substances)
Which group in the periodic table tends to have high electronegativity values?
the halogens
What is the correct IUPAC name for V₂S₃?
vanadium (III) sulfide