C. marbles placed inside hollow sphere
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Answer:
n = 0.0814 mol
Explanation:
Given mass, m = 35.7g
The molar mass of Tin(IV) bromate, M = 438.33 g/mol
We need to find the number of moles of bromine. We know that,
No. of moles = given mass/molar mass
So,

So, there are 0.0814 moles of bromine in 35.7g of Tin(IV) bromate.
Answer:
1) The elements have filled valence levels.
Explanation:
Since they have filled valence levels, they're stable and don't need to electrons to fill their valence shells since they're already full.
2) False, They do have electrons
3) False, He does have only one electron shell, but going down the periods, every next element have one more electron shell than a preceding one has.
4)False, they're actually the smallest atoms of their respective period
Answer:
OPTION (A) : Testing a rock sample for gold content
Explanation:
For testing a rock sample of gold content you will need a Chemist. To test the material, the sample is rubbed on black stone which will leave a mark on the stone. This mark is tested by applying aqua fortis i.e nitric acid on the mark. If the mark gets dissolve then the material is not gold. If the mark sustain the it is further tested by applying aqua regia i.e nitric acid and hydrochloric acid which will prove the sample is of gold if it gets dissolve on using hydrochloric acid. The purity of the sample can be checked by differing the concentration of the aqua regia and comparing it with the gold material of the known purity.