Which of the following can be used to measure absolute time? select all that apply.
varv...
Chemistry, 16.12.2019 18:31 jacquelinegonz
Which of the following can be used to measure absolute time? select all that apply.
varves
tree rings
law of superposition
ratio of c-12 to c-14 in a bone sample
which statements are true? select all that apply.
an atom is the smallest complete part of an element.
an element is a pure substance made of one kind of atom.
the nucleus is the tiny center of an atom, and it contains protons and neutrons.
isotopes are atoms of the same element that contain the same number of neutrons but different numbers of protons.
the time required for one-half of the atoms from a sample of a radioactive substance to decay is called its
half-life
beta decay
alpha decay
isotope number
which statements about radiocarbon dating are true? select all that apply.
it's useful for dating all inorganic things.
it's useful for dating some organic (once-living) things.
it's useful for dating some materials that are millions of years old.
it's useful for dating some materials that are thousands of years old.
for a living organism, which of the following are true? select all that apply.
the ratio of c-14 to c-12 remains constant.
the ratio of c-14 to c-12 increases over time.
the ratio of c-14 to c-12 decreases over time.
the amount of c-14 is less than the amount of c-12.
potassium-40 (k-40) decays into argon-40 (ar-40). after 1.25 billion years, 20 grams of k-40 would be reduced to 10 grams. how much of the original k-40 would remain after 5 billion years?
0 grams
1.25 grams
2.5 grams
5 grams
uranium-238 (u-238) decays into lead-206 (pb-206). which of the following are true statements? select all that apply.
u-238 is the parent, and pb-206 is the daughter.
u-238 is the daughter, and pb-206 is the parent.
a rock sample containing a relatively small amount pb-206 is old.
a rock sample containing a relatively small amount of pb-206 is young.
if a sample is thought to be several million years old, which method would best to determine its absolute age?
c-14/c-12
ar-40/k-40
pb-206/u-238
a fossil bone is tested, and no c-14 is found. what can be said about the fossil's age?
it is 5,730 years old.
it is less than 5,730 years old.
it is more than 5,730 years old.
absolute-age dating techniques can be used to determine the age of which of these? select all that apply.
earth
some rocks
some fossils
substances made entirely of pb-206
substances made entirely of ar-40
Answers: 1
Chemistry, 21.06.2019 21:40
It is important to wear proper protective equipment in lab even when not actively performing experiments because accidents can affect any researcher, even one not working on an experiment. select the best answer from the choices provided
Answers: 3
Chemistry, 22.06.2019 08:30
The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.
Answers: 1
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The reactions of photosynthesis occur in the of plant cell? a.mitochondria. b. lysosomes. c. chloroplasts. d. chlorophyll
Answers: 1
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