(2) 2 - 7 - 18 - 7 does, because the electron from the L shell jumped to the N shell, which requires energy.
The rest of them are either different types of atoms (different elements) or are not the excited state (ground state)
Answer: C. The number of collisions of gas particles decreases
Explanation: As temperature decreases so does everything else same with increase.
984 grams of strontium will be recovered from 9.84x10^8 cubic meter of seawater.
Explanation:
From the question data given is :
volume of strontium in sea water= 9.84x10^8 cubic meter
(1 cubic metre = 1000000 ml)
so 9 .84x10^8 cubic meter
= 984 ml.
density of sea water = 1 gram/ml
from the formula mass of strontium can be calculated.
density = 
mass = density x volume
mass = 1 x 984
= 984 grams of strontium will be recovered.
98400 centigram of strontium will be recovered.
Strontium is an alkaline earth metal and is highly reactive.
Answer:
Soluble salts can be made by reacting acids with soluble or insoluble reactants. Titration must be used if the reactants are soluble. Insoluble salts are made by precipitation reactions.
Making insoluble salts
An insoluble salt can be prepared by reacting two suitable solutions together to form a precipitate.
Determining suitable solutions
All nitrates and all sodium salts are soluble. This means a given precipitate XY can be produced by mixing together solutions of:
X nitrate
sodium Y
For example, to prepare a precipitate of calcium carbonate:
X = calcium and Y = carbonate
mix calcium nitrate solution and sodium carbonate solution together
calcium nitrate + sodium carbonate → sodium nitrate + calcium carbonate
Ca(NO3)2(aq) + Na2CO3(aq) → 2NaNO3(aq) + CaCO3(s)
It also works if potassium carbonate solution or ammonium carbonate solution is used instead of sodium carbonate solution. Remember that all common potassium and ammonium salts are soluble.
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Explanation:
Answer:
Flashlight
Explanation:
A flashlight gives out heat
hope this helps...
