The number of moles in 2.154 x 10⁻¹ kg of Al is 7.984.
<h3>What is a Mole?</h3>
- A mole is a unit used to describe the amount of substance that has exactly the same number of elementary particles as there are atoms in 12 grams of Carbon - 12.
- A mole has 6.022 x 10²³ elementary particles (atoms, ions or molecules, etc.). This fixed quantity is known as Avagadro's Number.
The molar mass of Al = 26.98 gmol⁻¹
Given the mass of Al = 2.154 x 10⁻¹ kg = 215.4 g
Number of moles given by
where m = given mass of the compound
M = Molar mass of the compound
The number of moles of Al = = 7.984 moles
Hence, the number of moles of Al is 7.984 moles.
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Half life is defined as the amount of time it takes for a radioactive material to divide itself into half after radioactive decay process. So basically, after the prescribed half-life, what transforms to another material is 1/2 of the original and what is left is 1/2 as well. In this case, the formula applicable is
ln N/No = -kt
where N represents the masses before and after decay, t is the time elapsed and k is the decay rate constant.
Substituting,
ln 10/40 = -k*20
-k = <span>-0.0693
To find t1/2 or half life, then
ln 0.5 = -k*t1/2
t1/2 = ln 0.5 / 0.0693 = 0.1 minutes
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Answer:
Explanation:
18.01528 g/mol. I googled this, but it would be 16 for O plus 2 for the 2 H's. 18 g/mol divided by 12.5g=1.44 mol of H20.
1.44mol* molecules/mol= 8.6688*10^23.
Answer:
the answers are either a or d
Explanation:
Answer:
D. Ash is a different substance than wood.