79 terms

GES 105 Final (Need to finish)

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Any material that is made up of only one type of atom is classified as
an element
The periodic table lists
more than 100 elements
The most abundant element in the universe is
hydrogen
The origin of the elements is
the stars
What is known about atoms is that they are
perpetually moving, tinier than the wavelengths of visible light, recycling among innumerable forms.
What is known about atoms is that they are
mostly empty space
Which of the following particles are electrically neutral?
neutron
The symbol CO denotes
the combination of carbon and oxygen
The atomic number of an element matches the number of
protons in the nucleus of an atom
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. Why?
Helium is most similar to other group 8A elements
The radioactive decay of nature's elements occurs in the
soil we walk on, air we breathe, interior of Earth
Most of the radiation in Earth's biosphere
occurs as natural background radiation
Of alpha, beta, and gamma radiation, two are high -speed particles, and the one that isn't is
gamma
Which of these is actually a high-speed electron?
beta
Which of these cannot be separated by electrical or magnetic means?
gamma
Which of these is the most penetrating in common materials?
gamma
Which of these radioactive elements is gaseous at everyday temperatures?
radon
When food is exposed to gamma radiation, the food
doesn't become radioactive at all
A certain isotope has a half-life of one day. This means the amount of that isotope remaining at the end of four days will be
one-sixteenth
When an element ejects an alpha particle, the mass number of the resulting element
reduces by 4
Is chemistry the study of the submicroscopic, the microscopic, or the macroscopic, or all three?
All of the above, because most everything is made of atoms and molecules.
The phase in which atoms and molecules no longer move is the
none of the above
The first box in question 26 shown below represents which kind of matter?
a compound
Which has stronger attractions among its submicroscopic particles: a solid at 25°C or a gas at 25°C?
The attractions within the solid must be stronger than the attractions among the particles of the gas.
What is the gas found within a bubble of boiling water?
water vapor
Physical or chemical change? see picture
Chemical, because the atoms are connected differently
Atomic clocks are used in?
GPS
What is the difference between a compound and a mixture?
The components of a mixture are not chemically bonded together.
Classify the following changes as physical or chemical: Wood burns to ashes; water begins to boil; grass grows.
Chemical; Physical; Chemical
What chemical change occurs when a wax candle burns?
The heated wax molecules combine with oxygen molecules.
How many valence electrons does helium have?
two
How many bonds is oxygen able to make?
two
The argon atom tends NOT to gain any additional electrons because
there is no more room available in its outermost occupied shell.
Magnesium ions carry a 2+ charge, and hydroxide ions carry a 1- charge. What is the chemical formula for the ionic compound magnesium hydroxide?
Mg(OH)2
An atom loses an electron to another atom. Is this an example of a physical or a chemical change?
Chemical change involving the formation of positive ions.
Which has stronger attractions among its submicroscopic particles: a solid at 25°C or a gas at 25°C?
The attractions within the solid must be stronger than the attractions among the particles of the gas.
What is the difference between a compound and a mixture?
The components of a mixture are not chemically bonded together.
Classify the following bond as ionic, covalent, or metallic (Na, atomic number 11; Cl, atomic number 17
Na with Cl Na with Na Cl with Cl
ionic, metallic, covalent
Which bond is most polar?
O-H
Atoms of metallic elements can form ionic bonds, but they are not very good at forming covalent bonds. Why?
hey have a great tendency to lose electrons.
When nitrogen and fluorine combine to form a molecule, the most likely chemical formula is
NF 3
Which of the following substances should be most soluble in hexane, CH3 CH 2 CH 2 CH 2 CH 2 CH3 ?
I 2
Many dry cereals are fortified with iron, which is added in the form of small iron particles. How might these particles be separated from the cereal?
Collect the iron filings with a magnet.
Would you expect to find more dissolved oxygen in cold polar or warm tropical ocean waters?
Polar oceans, because the solubility of oxygen in water decreases with increasing temperature.
How would you respond in defense of water's purity if it contained 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.
What is the molarity of 10 liters of a solution with 3 moles of sodium cyanide in it?
0.3 molar
Soap attracts "grime" by which type of molecular interaction?
Induced dipole-induced dipole.
Which of the following is not a method of disinfecting drinking water?
Aeration
Milk is an example of a
Homogenous suspension
Which of the following would be considered pure?
Baking soda
Salt water is an example of a
Homogenous solution
What is the solvent in air?
Nitrogen
Balance this equation:
___CH4 + ___O2 → ___CO2 + ___H2O
1,2,1,2
How many moles are there in 100 g of chlorine gas?
1.43
What is the molarity of a solution containing 500 grams of sodium chloride in 1L of water?
8.5 M
What volume of solution would be needed to make a 0.5 M NaOH solution using 20 grams of the compound?
1000 mL
Water, H 2 O, has a formula mass of 18. How many moles of water are there in 18 grams of water?
1 mole
How many grams of water, H 2 O, are there in 2 moles of water?
36 grams
How many moles of sucrose, C 12 H 22 O 11 ( 342g/mol), are there in 200 grams of sucrose?
0.585 moles
How much do Avogadro's number of sulfur atoms weigh?
32 g
What is the percent carbon in ethanol, C 2 H 5 OH?
52%
How many moles of oxygen, O 2 , can be produced from two moles of KClO 3 ?
2 KClO 3 →2 KCl + 3 O 2
3 mole
What is the relationship between a hydroxide ion and a water molecule?
A hydroxide ion is a water molecule minus a hydrogen nucleus.
Water is formed from the reaction of an acid and a base. Why is it not classified as a salt?
Not all acid-base reactions produce salts, as is the case with the formation of water.
Which salt forms from the reaction of hydrogen chloride, HCl, with potassium hydroxide, KOH?
KCl
Cutting back on the pollutants that cause acid rain is one solution to the problem of acidified lakes. Another solution would be to
add a neutralizing substance such as limestone.
How might warmer oceans accelerate global warming?
The heat collected by the ocean water would be radiated back into the atmosphere.
When water behaves as an acid, what does it lose?
A hydrogen ion
What element is oxidized in the following equation, and what element is reduced?
I 2 + 2 Br - →2 I - + Br 2
iodine, I, is reduced, while the bromine ion, Br - , is oxidized.
Which element behaves as the oxidizing agent in the equation in question 69, and which element behaves as the reducing agent?
For the equation in Question 69, the A. I 2 is the oxidizing agent, while the Br - is the reducing agent.
Identify the acid or base behavior of each substance in these reactions:
H 3 O+ + Cl - → H 2 O + HCl
H 3 O+ acts as an acid, Cl - acts as a base, H 2 O acts as a base, HCl acts as an acid.
A solution of pH=7 has an [H30+] = ? Remember pH=-log [H3O+]
10 -7
Why does the melting point of hydrocarbons increase as the number of carbon atoms per molecule increases?
Because of greater induced dipole-induced dipole molecular attractions.
What is radon at standard temperature and pressure?
A gas
Where is maximum attraction between molecules found?
Maximum attraction is found in solids and gradually less attraction is found in liquids, then in gases.
What is a physical change?
A physical change is a change of state of matter.
For example solid -> liquid
What is a chemical change?
A chemical change is when atoms in the reactant molecules break apart and form new molecules.
What is a compound?
A compound contains different atoms bonded together.
What is a mixture?
A mixture contains more than one kind of atom and molecule.