Answer:
Mass = 32 g
Explanation:
Given data:
Number of moles of oxygen = 1.0 mol
Mass of oxygen = ?
Solution:
Formula:
Number of moles = mass/molar mass
Molar mass of oxygen (O₂) is 32 g/mol
by putting values,
1.0 mol = mass/ 32 g/mol
Mass = 1.0 mol ×32 g/mol
Mass = 32 g
Answer:- B) Full ionic equation
Explanations:- A molecular equation does not have ions. It is the non charge form of the elements of compounds. When we write the full or total ionic equation for the molecular equation then ions are written for the aqueous species. The ions present on both sides(reactant and product sides) in a full ionic equation are known as spectator ions or common ions. These ions are canceled to get the net ionic equation. For example, reaction of aqueous solution of silver nitrate with aqueous solution of barium chloride to form aqueous solution of barium nitrate and a precipitate of silver chloride.
Balanced molecular equation:-

Full ionic equation:-

If we look at the above full ionic equation then barium ion and nitrate ions are the spectator ions are they are present on both sides.
So, while writing the net ionic equation, these spectator ions are canceled.
Net ionic equation:-

So, it is also clear from the above example that it's the full ionic equation that include spectator ions.
Answer: The empirical formula is 
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mas of H = 1.8 g
Mass of S = 56.1 g
Mass of O = 42.1 g
Step 1 : convert given masses into moles.
Moles of H =
Mass of S =
Moles of O=
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For H =
For S =
For O =
Converting to whole number ratios
The ratio of H: S: O= 2: 2: 3
Hence the empirical formula is 
There are 1,000m is 1k. So just move the decimal one position right. 127.56m
There are 10,000cm in 1k. Move the decimal two positions right. 1275.6cm