CHEM 1010 CHPT 3 - FARRELLY
How many different elements are in the compound C6H12O6?
3
What is the difference between a compound and a mixture?
A mixture can be physically separated into its components; a compound cannot be physically separated into its components.
Which of the following is an example of a physical change?
water boiling and being converted into steam
Which of the following would be considered a homogeneous mixture?
wine
Which atom is smallest?
Be
The atomic symbol for cobalt is ________.
Co
Oxygen atoms are used to make water molecules. Does this mean that oxygen, , and water, O, have similar properties?
No, compounds are uniquely different from the elements from which they're made.
Classify the following as element, compound, or mixture, and justify your classifications: sodium chloride, stainless steel, sugar, aluminum, ice.
compound; mixture; compound; element; compound
Which of these properties describes a metal?
conducts heat very well
If you have one molecule of CO2, how many molecules of O2 does it contain?
None, O2 is a different molecule than CO2.
Half-frozen fruit punch is always sweeter than the same fruit punch completely melted because ________.
crystallization is a purifying process
Which of the following would be considered a physical property?
density
What are metalloids?
elements that have some properties like metals and some like nonmetals
The four substances below are either elements or compounds. Which are which?
elements: o ☻☻ ; compounds: ☺☻ ☺☻☻
If you filter sea water to remove all of the particles you would be left with a clear ________.
homogeneous mixture called a solution
When blue food coloring is dissolved in water, the result is a ________.
homogeneous mixture called a solution
A chemical change involves a change in ________.
how atoms are bonded
Radioactive strontium, Sr (number 38), is especially dangerous to humans because it tends to accumulate in calcium-dependent bone marrow tissues (calcium, Ca, number 20). This fact relates to fact that strontium and calcium are both ________.
in group 2 of the periodic table
The repeating trends that take place when examining the elements are called ________.
periodicity
Which of the following describes a nonmetal?
poor conductor of electricity
Which of the following would be considered a chemical property?
reactivity towards water
Which of the following elements will most likely be shiny and flexible?
rhodium (Rh)
Which of the following elements is a transition metal?
silver (Ag)
What is the name of the following compound? NaF
sodium fluoride
What is the name of the following compound? SF3
sulfur trifluoride
Which of the following would not be considered a physical property?
temperature at which a material catches on fire
About how many elements do you have access to as a consumer of market goods?
ten
The oldest known elements in the periodic table are the ones ________.
that match their Latin names
Which chemical family is composed almost entirely of synthetic elements?
the actinides
How might you separate a mixture of sand and salt? A: with tweezers and a magnifying glass B: just add water C: heat the mixture until one of the components melts
A and B
The systematic names for water, ammonia, and methane are dihydrogen monoxide, O; trihydrogen nitride, N; and tetrahydrogen carbide, C. Why do most people, including chemists, prefer to use the common names for these compounds? (A) The common names are shorter and easier to pronounce. (B) These compounds are encountered frequently. (C) The common names are more widely known. (D) all of the above
(D) all of the above
Compared to microtechnology, nanotechnology focuses on a scale that is about ________.
1000 times smaller
How many atoms of Oxygen (O) are in HClO4?
4
If you have two molecules of TiO2, how many oxygen atoms would you have?
4
How many atoms are in one molecule of Na2SO4?
7
The boiling point of methanol is 65°C and the boiling point of ethanol is 78°C. Which of the following statements is true?
At 70°C you would have methanol gas and liquid ethanol.
Which of the following elements are in the same period as magnesium (Mg)?
Cl
Someone argues that he or she doesn't drink tap water because it contains thousands of molecules of some impurity in each glass. How would you respond in defense of the water's purity, if it indeed does contain thousands of molecules of some impurity per glass?
Compared to the billions and billions of water molecules, a thousand molecules of something else is practically nothing. Besides, it is impossible to obtain perfectly pure bottled water either.
Which element would have chemical properties the most similar to chlorine (Cl)?
I
Which atom is largest?
Rb
If you eat metallic sodium or inhale chlorine gas, you stand a strong chance of dying. Let these two elements react with each other, however, and you can safely sprinkle the compound on your popcorn for better taste. What is going on?
Sodium chloride has nothing in common with the properties of the elements sodium and chlorine.
Why isn't dirt listed in the periodic table?
The periodic table lists only elements made of one kind of material. Dirt is a mixture of elements and compounds.
Why can't the elements of a compound be separated from one another by physical means?
Their atoms are too tightly bound to one another.
What do chicken noodle soup and garden soil have in common?
They are both examples of heterogeneous mixtures.
Which of the following physical properties would you expect for krypton (Kr)?
a gas at room temperature
How would you classify the following material? a cappuccino (with foam)
a heterogeneous mixture
Water and ethanol can be separated by heating the ethanol until it boils away from the water. What type of change is this?
a physical change
How would you classify the following material? coffee (black)
a solution
How would you classify the following material? coffee (with milk)
a suspension
How would you classify the following material? milk
a suspension
Which of the following images could describe an element at the atomic level?
all of the images
Which of the following is a metalloid?
antimony (atomic no. = 51)
Which of the following elements is a gas at room temperature?
argon (Ar
What is the name of the following compound? CaCl2
calcium chloride
What is the name of the following compound? CO2
carbon dioxide
A chemical reaction is synonymous to a ________.
chemical change
A compound is represented by the ________.
chemical formula
Classify the following changes as physical or chemical. Wood burns to ashes; water begins to boil; grass grows; a rock is crushed to powder.
chemical; physical; chemical; physical
Which of the following elements is a halogen?
chlorine (Cl)
A combination of two or more substances in which the participants (reactants) no longer retain their individual chemical properties is called a(n) ________.
compound
The probe tip of a scanning probe microscope ________.
floats above the atoms of a sample
Which of the following is an example of a chemical change?
gasoline being used in the engine of a car producing exhaust
Elements that are in the same ________ have a tendency to have very similar chemical properties due to periodic trends.
group
Which of the following is not the name of a chemical family?
heavy metals
Helium, He, is a nonmetallic gas and the second element in the periodic table. Rather than being placed adjacent to hydrogen, H, however, helium is placed on the far right of the table because ________.
helium is most similar to other group 18 elements
Is the air in your house a homogeneous or heterogeneous mixture?
heterogeneous because of the dust particles it contains
The element silicon has a melting point of 1,410°C and a boiling point of 2,355°C. It is a weak conductor of electricity, its density is 2.3 grams per cubic centimeter and it easily forms silicon dioxide when exposed to air. Which of the following is a chemical property of silicon?
its ability to react with oxygen to form silicon dioxide
Which of the following elements is an alkali metal?
lithium (Li)
A sample of iron weighs more after it rusts because ________.
of the additional oxygen it contains
Which of the following boxes represents a compound?
only C
Which of the following would not be considered a chemical property?
the temperature at which a liquid will boil
Which of the following is a metal?
titanium (atomic no. = 22)
