Atomic mass number of first 30 elements
1 answer:
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The question is incomplete. The complete question is:
The half-life for the decay of carbon-14 is 5.73x10^3 years. Suppose the activity due to the radioactive decay of the carbon-14 in a tiny sample of an artifact made of woodfrom an archeological dig is measured to be 2.8x10^3 Bq. The activity in a similiar-sized sample of fresh wood is measured to be 3.0x10^3 Bq. Calculate the age of the artifact. Round your answer to 2 significant digits.
Answer:
570 years
Explanation:
The activity of the fresh sample is taken as the initial activity of the wood sample while the activity measured at a time t is the present activity of the wood artifact. The time taken for the wood to attain its current activity can be calculated from the formula shown in the image attached. The activity at a time t must always be less than the activity of a fresh wood sample. Detailed solution is found in the image attached.
Answer:
0.00 g
Explanation:
We have the masses of two reactants, so this is a limiting reactant problem.
We will need a balanced equation with masses, moles, and molar masses of the compounds involved.
1. Gather all the information in one place with molar masses above the formulas and masses below them.
Mᵣ 30.07 32.00
2CH₃CH₃ + 7O₂ ⟶ 4CO₂ + 6H₂O
Mass/g: 1.50 11.
2. Calculate the moles of each reactant
3. Calculate the moles of CO₂ we can obtain from each reactant
From ethane:
The molar ratio is 4 mol CO₂:2 mol C₂H₆
From oxygen:
The molar ratio is 4 mol CO₂:7 mol O₂
4. Identify the limiting and excess reactants
The limiting reactant is ethane, because it gives the smaller amount of CO₂.
The excess reactant is oxygen.
5. Mass of ethane left over.
Ethane is the limiting reactant. It will be completely used up.
The mass of ethane left over will be 0.00 g.