An exothermic reaction is just where heat is released. So basically if heat is released during the reaction is is an exothermic one.
Answer:
Two Sections that contain nitrogen of a nucleotide that bond together to connect strands of DNA or RNA.
Explanation:
Answer:
100 grams of C-14 decays to 25 grams in 11,460 years.
The C-14 isotope is only useful for dating fossils up to about 50,000 years old
If an ancient bone contains 6.25% of its original carbon, then the bone must be 22,920 years old.
Explanation:
We already know that the half life of C-14 is 5,730 years. After the first half life, we have 50 grams remaining. This takes 5,730 years. After the second half life (11,460 years now gone) we have 25 grams of C-14 left.
If a fossil material is older than 50,000 years an undetectable amount of 14C is left in the sample hence Carbon-14 is no longer suitable for dating the sample.
From;
0.693/5730 = 2.303/t log (No/0.0625No)
Where;
t = time taken and No = initial amount of C-14
0.693/5730= 2.77/t
t = 22,920 years
Answer:
Astatine is a halogen with several isotopes that all have short half-lives.
Which of the following combinations of mass number and neutrons are possible as isotopes of astatine? Choose one or more:
i) A = 211, n = 127
ii) A = 210, n = 125
iii) A = 220, n = 134
iv) A = 207, n = 122
v) A = 209, n = 124
Explanation:
The mass number is the sum of the number of protons and the number of neutrons in an atom.
Atomic number of At(astatine ) =85
That means it has --- 85protons.
Its mass number A=210
Hence, the number of neutrons in At are:
Second option:
ii) A=210 , n=125 is the answer.
Answer:
A) The data to support his hypothesis, so he should investigate if the same change happens in the density of solid water.
