Explanation:
Archaeologists use that assumption, called the law of superposition, to help determine a relative chronology for the site itself. Then, they use contextual clues and absolute dating techniques to help point to the age of the artifacts found in each layer.
Answer:
01) Cu tting hair is a physical change. reason-1
02) Cooking can be either one, but I would choose chemical reason-3
03) Ice cream melting is a physical change reason-2
Explanation:
When this is the first order reaction of the radioactive decay:
and according to the first order rate equation:
㏑(Ao/A) = K t
and when Ao = is the starting concentration
and A = is the concentration at time t
and K is the rate constant
t is the elapsed time = 14.26 days
for 1 half-life ∴ Ao/A = 2
by substitution:
㏑2 = K * 14.26 days
∴ K = 0.0486 days^-1
Answer:
120 grams
Explanation:
Data:
Volume = V= 2 L
Molarity = 1.5 M
Molecular masses:
Na = 23, O= 16, H=1
Total molecular mass =M= 23+16+1 = 40
mass = m = ?
To find the mass we need to find moles from molarity formula:
Molarity = n/V
n= Molarity x V
= 1.5 x 2
n= 3 moles
Now we can find mass:
number of moles = given mass / molecular mass
n = m/M
m= n x M
= 3 x 40
m = 120 grams
