Ferromagnesian silicate minerals (i looked it up)
Answer:
Explanation:
The half-life of K-40 (1.3 billion years) is the time it takes for half of it to decay.
After one half-life, half (50 %) of the original amount will remain.
After a second half-life, half of that amount (25 %) will remain, and so on.
We can construct a table as follows:
No. of Fraction
<u>half-lives</u> <u> t/yr </u> <u>Remaining</u>
0 0 1
1 1.3 billion ½
2 2.6 ¼
3 3.9 ⅛
We see that after 2 half-lives, ¼ of the original mass remains.
Conversely, if two half-lives have passed, the original mass must have been four times the mass we have now.
Original mass = 4 × 2.10 g = 
In, 1937 Lawrence, in operating his cyclotron, bombarded a molybdenum-96 foil with deuterium ions (2h), producing for the first time an element not found in nature. He was initially unaware that the radioactivity produced by the "bombarded foil" was not from molybdenum but from a new, artificial element. It was his cooperation with Italian-American physicist <span>Emilio Segrè </span>that allowed the new element to be discovered. The answer is Technetium: Tc
The conversion factor for volume at STP is

or

. Since we want volume, we would use

. We conclude with the following calculations:

The answer is 9.744L H2
Gay-Lussacs law states that pressure of a gas is directly proportional to temperature when the volume is kept constant
P / T = k
where P - pressure , T - temperature in kelvin and k - constant

where parameters for the first instance are on the left side of the equation and parameters for the second instance are on the right side of the equation
T1 - 25 °C + 273 = 298 K
substituting the values in the equation

T2 = 388 K
temperature in celcius - 388 K - 273 = 115 °C
answer is C. 115 °C