Answer:
1. A
2. D
3. D
4. B
Explanation:
Sulfer is in the 3rd period of the periodic table meaning that 2 periods came before it hence the 2 electron shells and it is in the 6th group hence the 6 valence electrons.
Using this logic we know that the element in the 5th period and the 7th group which would be Iodine
We also know that the element in the 4th period and 8th group is Krypton
The Lewis dot model is more commonly used to show chemical reactions, I haven't heard of the addition or subtraction models before so there's a chance that it may only be part of your curriculum, or they are answers made up for your multiple choice.
Hope this helps!!!
Its basically a chart with all the known elements on it. The elements are organized by period and group. Period and group are determined by the number of protons and electrons an atome has.
Answer:
The molecular weight of the unknown compound is 267.7 g/mol
Explanation:
Lowering vapor pressure → Colligative property where the vapor pressure of solution is lower than vapor pressure of pure solvent
ΔP = P° . Xm
0.526 atm - 0.501 atm = 0.025atm
0.025 atm = 0.526 atm . Xm
Xm = 0.025 atm / 0.526 atm → 0.0475 (mole fraction)
Mole fraction = Moles of solute / Total moles (solute + solvent)
0.0475 = Moles of solute / Moles of solute + Moles of solvent
We determine the moles of solvent → 116.2 g . 1mol / 58 g = 2 moles
0.0475 = Moles of solute / Moles of solute + 2
0.0475 moles of solute + 0.095 = Moles of solute
0.095 = Moles of solute - 0.0475 moles of solute
0.095 / 0.9525 = Moles of solute → 0.0997 moles
Molas mass = g/mol → 26.7 g / 0.0997 mol = 267.7 g/mol
Ammonia is formed by a reaction between hydrogen and nitrogen as shown by the equation below.
N2(g) + 3H2(g) = 2NH3(g)
1 mole of ammonia contains 17 g
Therefore 10.78 g of ammonia are equivalent to 10.78/17 = 0.6341 moles
The mole ratio of hydrogen to ammonia is 3 : 2
Therefore, moles of hydrogen used will be 0.6341 × 3/2 = 0.9512 moles
1 mole of hydrogen is equivalent to 2 g
Thus, the mas of hydrogen will be 0.9512 moles × 2 = 1.9023 g
Answer:
Option C:- that is equal to mass of an proton.
Explanation:
Protons and neutrons have approximately the same mass, about 1.67 × 10-24 grams, which scientists define as one atomic mass unit (amu) or one Dalton. While electron has mass of 9.31 ×10⁻¹⁹.
