Answer and Explanation:
It's very important to assume that the rate of radioactive decay will remain constant over time to make scientists' lives easier when calculating the ages of fossils, compounds, etc.
If the rate changes, it would be extremely challenging for people to figure out the relative ages of rock strata, fossils, or other substances with radioactive elements in them. This is a fundamental assumption in order to be able to use radioactive dating.
Hope this helps!
Answer:
True
Explanation:
The physical changes are reversible in most cases and these changes are not the chemical changes which means that it is only the change in its state not in their nature. Just take the example of water, on cooling it becomes solid and change in color can be seen which is white in solid form and colorless in liquid form. This is also reversible and is a physical change. This means that physical changes can be identified at macroscopic level. Hence the answer is true.
<span>the elements in groups1a, 2a, 3a have positive charges according to their group numbers</span>
The metal component of the given compound, CrCl3, is chromium. The number of moles per 1 g of chromium is calculated through the equation below,
n = (1 g Cr)(1 mol Cr/51.996 g Cr)
n = 0.0192 mol Cr(3 electrons/1 mol Cr)
n = 0.0577 e-
Determine the number in charge by multiplying with Faraday's constant,
C = (0.0577 mol Cr)((1 F/1 mol e-)(96485 C/ 1F)
C = 5,566.87 C
Then, calculate time by dividing the charge with the current,
t = 5566.87 C/1.5 A
t = 3711.25 minutes
t = 61.84 hours
<span><em>Answer: 61.84 hours</em></span>
