Carbon-14 is radioactive isotope of carbon.
Carbon is essential element of living cells. While the living cells are alive, the carbon contained in them are in equilibrium with the carbon in atmosphere. But, once the cell dies, the carbon-14 isotope undergoes radioactive decay. By measuring the carbon-14 in atmosphere to the carbon-14 in dead organism, we can calculate the time (or years) that organism have died.
However, carbon-14 dating technique is not accurate for estimating the age of materials older than 50,000 years old (above 40,000 years). This is because, 99% of carbon is carbon-12, 1% is carbon-13 and trace remaining is the carbon-14. This means, carbon-14 is found in very trace amount, in fact 1 part per trillion of carbon atoms present is carbon-14. The half of life of carbon-14 is 5,730 years. For dating the organism, we use the concept of half lives of the carbon-14 isotope in the dead organisms and calculate how many half life old the sample is. But as the years increases, the number of carbon-14 isotope becomes too low to detect and make accurate calculation.
This means, at some point the organism can simply run out of carbon-14.
Hence carbon-14 dating is not accurate for estimating age of materials older than 50,000 years old.
The new volume if the balloon is cooled at constant pressure is 3.98 L.
Charles's law, states that the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature if the pressure remains constant.
The new volume is calculated using the Charles law formula
V₁ / T₁ = V₂ / T₂
where,
V₁ = The initial volume of air = 4.24 l
T₁ = 23.00 °C into kelvin = 23 +273 =296 K
T₂ = 5.00 °C into kelvin = 5.00 + 273 = 278 K
V₂ = ?
By making V₂ subject the subject of the formula by multiplying both sides by T₂
V₂ = ( V₁ × T₂ ) / T₁
V₂ = (4.24 L × 278 K) / 296 k
= 3.98 L
Therefore, the new volume, if the balloon is cooled at constant pressure, is 3.98 L.
An air-filled balloon will contract when chilled and expand when heated. This occurs because the gas that makes up the air within the balloon expands when it is warm and contracts when it is cool.
Learn more about Charles law here:
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a) (NH4)2SO4 --- 1 mole of it contains 2 moles of N, 8 moles of H, 1 mole of S, and 4 moles of O.
MM = (2 moles N x 14.0 g/mole) + (8 moles H x 1.01 g/mole) + (1 mole S x 32.1 g/mole) + (4 moles O x 16.0 g/mole) = 132 g/mole.
6.60 g (NH4)2SO4 x (1 mole (NH4)2SO4 / 132 g (NH4)2SO4) = 0.0500 moles (NH4)2SO4
b) The molar mass for Ca(OH)2 = 74.0 g/mole, calculated like (NH4)2SO4 above.
4.5 kg Ca(OH)2 x (1000 g / 1 kg) x (1 mole Ca(OH)2 / 74.0 g Ca(OH)2) = 60.8 moles Ca(OH)2
Answer:
B. Hypothesis
Explanation: A hypothesis is a guess of what will or might happen before an experiment.
