Chlorine is the most electronegative
Answer:
They decrease, because of the stronger effective nuclear charge.
Explanation:
- Atomic radii decreases from left to right across a period.
- This is due to the increase in the no. of protons and electrons through the period.
- One proton has a greater effect than one electron.
- So, electrons are attracted towards the nucleus and resulting in a smaller atomic radii.
<em>Thus, the right choice is: They decrease, because of the stronger effective nuclear charge.</em>
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1 mol of any gas or mix of gases at STP conditions will have a volume of 22.4 L. Since the problem doesn’t said what are the conditions I will asume that are STP condition and the volume of one mole of the mix will have a volume of 22.4 L.
You may know that density is
D=m/v
In one mole of air I will have 80% of Nitrogen (N2) and 20% oxygen (O2).
So the mass of one mole of air will be
14 x2x0.80+16x2x0.20 = 22.4 g + 6.4 g = 28.8 g
D= 28.8/22.4 = 1.28 g/L
Of course if the temperature is higher the density will be smaller because the volume of one mole will be bigger and viceversa if the temperature decrease. Also if the pressure is different than one atm the volume of a mol will change.
a) (NH4)2SO4 --- 1 mole of it contains 2 moles of N, 8 moles of H, 1 mole of S, and 4 moles of O.
MM = (2 moles N x 14.0 g/mole) + (8 moles H x 1.01 g/mole) + (1 mole S x 32.1 g/mole) + (4 moles O x 16.0 g/mole) = 132 g/mole.
6.60 g (NH4)2SO4 x (1 mole (NH4)2SO4 / 132 g (NH4)2SO4) = 0.0500 moles (NH4)2SO4
b) The molar mass for Ca(OH)2 = 74.0 g/mole, calculated like (NH4)2SO4 above.
4.5 kg Ca(OH)2 x (1000 g / 1 kg) x (1 mole Ca(OH)2 / 74.0 g Ca(OH)2) = 60.8 moles Ca(OH)2
