Half-life of a radioactive substance is the time required to reduce the amount of substance to half of its initial amount.
In present case, half-life is material is given as 1000 years and initial amount of material is given as 400 kg
Answer 1) Since, half-life of radio-active substance is 1000 years, therefore after 1st half life, amount of the material will be left to half the initial amount. Hence, amount of substance left after 1000 years = 400/2 = 200 kg.
Answer 2) For 2000 years, radioactive material has crossed 2 times the half life. Therefore , amount of the material will be left to 1/4 the initial amount. Hence, amount of substance left after 2000 years = 400/4 = 100 kg.
Answer 3) For 4000 years, radioactive material has crossed 4 times the half life. Therefore , amount of the material will be left to 1/16 the initial amount. Hence, amount of substance left after 4000 years = 400/16 = 25 kg.
Answer:
with the molecular formula C3H5(ONO2)3, has a high nitrogen content (18.5 percent) and contains sufficient oxygen atoms to oxidize the carbon and hydrogen atoms while nitrogen is being liberated, so that it is one of the most powerful explosives known.
Explanation:
NTG reduces preload via venous dilation, and achieves modest afterload reduction via arterial dilation. These effects result in decreased myocardial oxygen demand. In addition, NTG induces coronary vasodilation, thereby increasing oxygen delivery.
Answer:
The energy produced equals 140.760 kJ
Explanation:
The relation between power, current and voltage is
Applying the given values in the relation above we get
Now Since 
Again applying the calculated values we get
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Ch.2 - Atoms & ElementsSee all chapters
Atomic Theory
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Solution: Which of the following chemical reactions is/are NOT possible according to Dalton's atomic theory?a. reaction 1: CCl4 → CH4b. reaction 2: N2 + 3H2 → 2NH3c. reaction 3: 2H2 + O2 → 2H2O + Au
Problem
Which of the following chemical reactions is/are NOT possible according to Dalton's atomic theory?
a. reaction 1: CCl4 → CH4
b. reaction 2: N2 + 3H2 → 2NH3
c. reaction 3: 2H2 + O2 → 2H2O + Au
Answer:
0.52 mol
Explanation:
Using the general gas equation formula:
PV = nRT
Where;
P = pressure (atm)
V = volume (Liters)
n = number of moles (mol)
R = gas law constant (0.0821 Latm/molK)
T = temperature (K)
At STP (standard temperature and pressure), temperature of a gas is 273K, while its pressure is 1 atm
Using PV = nRT
n = PV/RT
n = (1 × 11.74) ÷ (0.0821 × 273)
n = 11.74 ÷ 22.41
n = 0.52 mol
There are 0.52 moles in the basketball
