Answer: X could represent the element of oxidation state (+2) such as (Mg2+, Pb2+, Ba2+, Ca2+, Ba2+, Zn2+, ....etc)
Explanation:
- The formula of the compound XSO4 is a neutral compound that the algebraic summation of the oxidation states of different elements in it must be zero.
- The group SO4 has the oxidation state (2-), that S has (6+) oxidation state and O has (2-) oxidation state, so the oxidation of SO4 = (6+) + (-2*4) = -2.
- It is clear that X must have the oxidation state 2+.
- So, X could be represents by many different elements such as (Mg2+, Pb2+, Ba2+, Ca2+, Ba2+, Zn2+, Fe2+, ....etc)
First, we will get the "n", the number of half lives, it is the elapsed time over the half life. In the problem, the time is measured in days, so we have
6/2 = 3
to get the ending amount of radioactive sample, we have
32g x (1/2)³ = 4 grams of radioactive sample ⇒ the amount left after 6 days
Answer: D
Explanation: Keeping the pressure constant and increasing the temperature.
Answer:
<em>2.5</em> moles of sodium phosphate
Explanation:
3 Pb(NO3)2 + 2 Na3PO4 → Pb3(PO4)2 + 6 NaNO3
6 (moles in the reaction)- 7.5(moles in the task)
2 (moles in the reaction)- x (moles in answer) ⇒6x = 2*7.5 ⇒ x = 15/6=2.5 (moles)
