Answer:-
Explanations:- Atomic number of Se is 34 and it forms after accepting two electrons and there becomes total 36 electrons to it.
Atomic number of Sr is 38 and it forms on losing two electrons from it's valence shell and there also becomes total 36 electrons to it.
Now, both of these are isoelectronic means having with equal number of electrons but the cation(positively charged ion) has more protons as compared to the anion(negatively charged ion) and because of this it has more effective nuclear charge and it's size is smaller.
The anion has less effective nuclear charge and so it's size is bigger.
Hence, the right choice is .
To find moles from grams divide the number of moles by the molar mass...
32.7g/18.01 which is 1.82 using significant figure rules
Answer:
0.768 kg
Explanation:
Step 1: Given data
- Mass of ammonium nitrate (solute): 27.8 g
- Molality of the solution (m): 0.452 m
Step 2: Calculate the moles corresponding to 27.8 g of ammonium nitrate
The molar mass of ammonium nitrate is 80.04 g/mol.
Step 3: Calculate the mass of water
The molality is equal to the moles of solute divided by the kilograms of solvent (water).
When the number of moles = mass/molar mass
so the number of moles of CO = mass of CO sample/molar mass of CO
when the mass of CO sample = 36.55 g
and the molar mass of CO = 12 + 16 = 28 g/mol
by substitution:
∴moles of carbon monoxide = 36.55 g / 28 g/mol
= 1.3 moles
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