Answer:
3.1% is the fraction of the sample after 28650 years
Explanation:
The isotope decay follows the equation:
Ln[A] = -kt + Ln[A]₀
<em>Where [A] could be taken as fraction of isotope after time t, k is decay constant and [A]₀ is initial fraction of the isotope = 1</em>
<em />
k could be obtained from Half-Life as follows:
K = Ln 2 / Half-life
K = ln 2 / 5730 years
K = 1.2097x10⁻⁴ years⁻¹
Replacing in isotope decay equation:
Ln[A] = -1.2097x10⁻⁴ years⁻¹*28650 years + Ln[1]
Ln[A] = -3.4657
[A] = 0.0313 =
<h3>3.1% is the fraction of the sample after 28650 years</h3>
<em />
Answer:
Explanation:
If we want to convert from grams to moles, the molar mass is used. This is the mass of 1 mole. They are found on the Periodic Table as the atomic masses, but the units are grams per mole (g/mol) instead of atomic mass units (amu).
Look up the molar mass of carbon.
Set up a ratio using the molar mass.
Since we are converting 3.06 grams to moles, we multiply by that value.
Flip the ratio. This way, the ratio is still equivalent, but the units of grams of carbon cancel.
The original measurement of grams (3.06) has 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place.
The 7 in the ten-thousandth place tells us to round the 4 up to a 5.
3.06 grams of carbon is approximately <u>0.255 moles of carbon.</u>
An hypothesis is the proposed explanation that is made on the basis of limited evidence and it serves as the starting point for further investigation while a problem statement is a clear, concise description of the problems which needs to be addressed.
Problem statement is used to concentrate the focus of the researcher at the beginning, to keep him on track during the operation and at the end it is used to evaluate if the process delivered an outcome that solve the problems.
Hypothesis is used to define the relationship between two variables at the end of the research the scientist has to decide when its starting hypothesis is valid or not.<span />
Answer:
[H⁺] = 5.011 × 10⁻³ mol.L⁻¹
Explanation:
The pH is converted into concentration of H⁺ as,
[H⁺] = 10^-pH
Where 10 is antilog,
So, putting values,
[H⁺] = 10⁻²·³
[H⁺] = 0.00501
Or,
[H⁺] = 5.011 × 10⁻³ mol.L⁻¹
