1st answer :- The two main methods of mineral formation are cooling and evaporation.
The number of years required for 1/4 cobalt-60 to remain after decay is calculated as follows
after one half life 1/2 of the original mass isotope remains
after another half life 1/4 mass of original mass remains
therefore if one half life is 5.3 years then the years required
= 2 x 5.3years = 10.6 years
P = pressure, V = volume, T = absolute temperature k = constant.
Avagadro's number is just a measurement. One mole is 6.022 X 10^23 of anything - atoms, molecules, marbles... anything.
<span>1) If one mole = 6.022 X 10^23, then 8.00mol of H2S is: </span>
<span>(3.00mol H2S) (6.022 X 10^23 molecules H2S / 1 mol H2S) = 1.8060 X 10^24 molecules H2S. </span>
<span>Rounded to 3 sig figs =1.81 X 10^24 molecules H2S
</span>part2.
<span> This one uses moles in the stoichiometric sense as well as the measurement. One formula unit of MgCl2 contains 1 mole Mg and 2 moles Cl. </span>
<span>First, figure out how many moles of formula units there are. </span>
(1.81 X 10^24 FU's) (1mol MgCl2 / 6.022 X 10^23 FU's) = 3.0056mol MgCl2.
<span>Now, we know that there are 2 moles of Cl in every mole of MgCl2 (2 Cl atoms in every unit of MgCl2). From this we can determine how many moles of Cl atoms there are: </span>
<span>(3.0056mol MgCl2) (2mol Cl atoms / 1mol MgCl2) = 6.0112mol Cl atoms. </span>
<span>Now round to 3 sig figs = 10.0mol Cl atoms</span>
If you double the concentration of A, the rate is doubled. If you doubled the concentration of B, since the rate law has B^2, the rate is multiplied by 4. If you double both A & B's concentrations, then the rate would be multiplied by 2*4 = 8, which is the last option.
