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Vocabulary
Random Questions
Random Questions
Random Questions
Random Questions
100
What is a chemical equation?
A compact notation for describing a chemical change.
100
What is an oxidation reaction?
Oxidation Involves Loss of electrons
100
Which element has the largest atoms? a. U b. Cs
b. Cs The incredible reactivity of cesium is due in part to the large size of its atoms.
100
Besides water, what chemical compound is used in greatest amounts by the global economy with little or no preprocessing? a. CaCO3 b. SiO2 c. cellulose
b. SiO2 Silicon dioxide in the form of sand and gravel is in greatest demand of the compounds listed. About 7.5 gigatons of sand and gravel were used in the world economy in 1983.
100
Which element can be drawn into thinner wires and hammered into thinner sheets than any other element? a. Au b. Mt c. Na
a. Au
200
What is a catalyst ?
A substance that increases the rate of a chemical reaction, without being consumed or produced by the reaction.
200
Which of the following salts has a solubility that decreases as temperature increases? a. Na2CO3 b. Li2CO3 c. K2CO3
b. Li2CO3 When you're looking for weird behavior within a group on the periodic table, the element at the top of the group is always a good bet. The lithium ion itself is very small, giving it a high charge density. It builds a large, ordered shell of waters around it at lower temperatures, which prevents it from being recaptured by the lithium carbonate crystal. At higher temperatures that shell is disrupted, and solubility decreases.
200
The candela is one of the seven base units in the SI system. It measures: a. luminance b. luminous intensity c. combustion rate
b. luminous intensity Luminance is measured in candelas per square meter.
200
What is "diamond ink"? a. colloidal diamond ink for marking metal b. colloidal silver ink c. a mixture of HF, BaSO4, and fluorides for etching glass d. carbon disulfide-based ink for marking diamonds
c. a mixture of HF, BaSO4, and fluorides for etching glass Diamond ink (or etching ink) is a milky white liquid which is shaken and warmed in a lead dish before used to etch marks in glass. It must be stored in plastic, rubber, or paraffin coated bottles.
200
Which of the following pH's for a rain sample would be considered "acid rain"? a. 5 b. 6 c. 7 d. 8 e. 4
e. 4 pH's below 5 indicate "acid rain". Even pure pre-industrial rainwater had a pH between 5 and 6 due to dissolved carbon dioxide equilibria (distilled water in contact with room air will have a pH significantly below 7, for the same reason).
300
What is SI unit for a substance?
A mole
300
What is aqua regia? a. a hormone produced by queen bees b. an acid mixture that dissolves gold c. a purple pigment d. supercooled water
b. an acid mixture that dissolves gold Aqua regia is a 1:3 or 1:4 mixture of HNO3 and HCl. It is called aqua regia because it attacks gold (the "king" of metals) by producing aqueous chlorine from oxidation of the HCl by the HNO3.
300
On the Fahrenheit scale, the coldest possible temperature is: a. -500°F b. -379.5°F c. 32°F d. -459.7°F e. 0°F
d. -459.7°F No temperature is colder than absolute zero, at -459.7°F (-273.15°C).
300
What is the minimum number of photons that must reach the retina each second to produce vision? a. 20 b. 9 c. 200
a. 20 Assuming the wavelength of light is 550 nm, and that vision persists for about 1/30 of a second, and that the threshold for incident radiation to trigger optic nerve impulses is 2×10-16 W, about 20 photons per second can be seen by the retina in the human eye when it is adapted to darkness.
300
Which of the following is NOT one of the basic building blocks of proteins? a. serine b. purine c. threonine
b. purine The common amino acids are alanine, arginine,asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. Purine isn't on the list.
400
What is a pH buffer?
A solution that can maintain its pH value with little change when acids or bases are added to it.
400
If water can dissociate, why doesn't hydrogen gas dissociate?
The first reaction (autoprotolysis of water) isn't a redox reaction; the second reaction you describe IS a redox reaction. So they're different in a very fundamental way.
400
Which of the following is the smallest container that could hide enough plutonium to make an atomic bomb capable of destroying 40 city blocks? a. a coffee can b. an automobile trunk c. a soft drink can d. a small van e. a suitcase
c. a soft drink can A soft drink can can hold enough plutonium to make up to six bombs with that capability, according to the U. S. Natural Resources Defense Council.
400
Which of the "rare" gases is the most common in the atmosphere? a. argon b. radon c. neon d. helium
a. argon Argon makes up a little less than 1% of the atmosphere. Helium is by far the most common of the rare gases in the universe- only hydrogen is more common. However, it is found in lower concentrations than argon in Earth's atmosphere, because atmospheric helium easily escapes into space.
400
What is the smallest mass ever measured directly by a weighing scale? a. a 22 femtogram graphite speck b. a 5 ng virus crystal c. an electron d. a 10 microgram bacterial cell
a. a 22 femtogram graphite speck
500
What is a elementary reaction?
A reaction that occurs in a single step. Equations for elementary reactions show the actual molecules, atoms, and ions that react on a molecular level.
500
On a clear, moonless night, it's still possible to see by the light of the sky. Where does most of the light come from? a. chemiluminescent chemical reactions b. the stars c. the Big Bang d. solar wind e. dust that scatters light all the way from the dayside of the earth
a. chemiluminescent chemical reactions - Ultraviolet light from the sun breaks air molecules into oxygen and nitrogen atoms, and it puts oxygen and nitrogen molecules into high-energy excited states. It also breaks water molecules apart, forming free radicals like OH. In the upper atmosphere, it takes a while for the broken pieces to find each other and recombine. The recombination is still occurring at night. When chemical bonds form, energy is emitted; in this case, as light. The light that is produced is called 'airglow' and it is brighter than all of the stars combined on a clear, moonless night.
500
The 1938 edition of the CRC handbook lists "Masurium" as an element. The element was named for the German province of Masur. What is the modern name for masurium? a. promethium b. astatine c. francium d. technetium
d. technetium
500
Who discovered actinium, element 89? a. Glenn Seaborg b. Pierre Curie c. Marie Curie d. André-Louis Debierne
d. André-Louis Debierne Debierne is credited with discovering actinium in 1899, while working with uranium decay products in the laboratory of Marie and Pierre Curie.
500
The 1938 edition of the CRC handbook lists "Alabamine" as an element. The element was named for the state of Alabama and had the symbol Ab. What is the modern name for alabamine? a. francium b. technetium c. astatine d. promethium
c. astatine