Answer:
90yrs
Explanation:
Half life is the time taken for half of an original radioactive material to decay by half.
For the sample;
Half - life = 45yrs
Original amount = 600cpm
Start Number of atoms
0yrs 600cpm
First half life
45yrs 300cpm
Second half life
90yrs 150cpm
Answer:
Carbon dioxide (CO₂) is an important green house gas. A small increase in the concentration of this gas can lead to the global rise in the surface temperature. Over the last 100 years, this gas has increased significantly. One of the main cause behind this the anthropogenic activities.
After the setup of the industrial revolution, there has been a large increase in this CO₂ concentration, as there are numerous large factories and indutries that releases this harmful gases. In addition to this, the burning up of fossil fuel also is responsible for the emission of large amount of carbon into the atmosphere.
Deforestation also is another cause, because trees are no longer there in vast quantities which takes up a large number of atmospheric carbon and in return liberates plenty of oxygen.
Thus, the activities done by man over the last century has led to the increase in the concentration of CO₂ into the atmosphere.
Answer:
2.28
Explanation:
HCl(l) ===> H+ + cl-
HCl is a very strong acid. Almost all of it will decompose to the right. That means the concentration of H+ is 0.00530
pH = - log [H+]
pH = - log[0.00530]
pH = - - 2.2757
pH = 2.2757
Rounded this 2.28
A) heating a pan of water until the water is all gone because then it would change from a liquid top a gas.
Calculate the food energy (joules/g) of one of your food
samples. one chemistry calorie is equal to 4.186 joules. convert the energy you
calculated to kilojoules (1 kj = 1000 j). since nothing is given, an example is
avocadoes have 160 cal/100 g serving
(160 cal/ 100 g)(4.186 J/ 1 cal) (1 kJ/1000 J) = 0.0067 kJ/g
