Answer:
Na2S
Explanation:
Na2S: Na (always +1). S (-2) in this formula
CaSO4: Ca (always +2). O (-2). => S (+6) in CaSO4
S (0)
SO2: O(-2) => S (+4)
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Given :
On a shelf sits a bottle of NaCl solutions with a molar concentration of 2.50 M and a total volume of 300 mL. If 15.0 mL of the solution is added to 985 mL of pure water .
To Find :
The molar concentration of NaCl in the new solution.
Solution :
Molarity M is given by :
Now , 1000 ml of NaCl contains 2.5 moles of NaCl .
So , 15 ml of NaCl contains :
New , volume V = 15 + 985 = 1000 ml = 1 L .
So , putting value of n and V in above equation :
Therefore , the molar concentration of NaCl in the new solution is 0.0375 M .
Hence , this is the required solution .
Answer:
Ca + Pb(NO3)2 → Pb + Ca(NO3)2
Explanation:
This is an oxidation-reduction (redox) reaction:
PbII + 2 e- → Pb0
(reduction)
Ca0 - 2 e- → CaII
(oxidation)
Pb(NO3)2 is an oxidizing agent, Ca is a reducing agent.