Answer:
the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
Answer:
the volume occupied by 3.0 g of the gas is 16.8 L.
Explanation:
Given;
initial reacting mass of the helium gas, m₁ = 4.0 g
volume occupied by the helium gas, V = 22.4 L
pressure of the gas, P = 1 .0 atm
temperature of the gas, T = 0⁰C = 273 K
atomic mass of helium gas, M = 4.0 g/mol
initial number of moles of the gas is calculated as follows;
The number of moles of the gas when the reacting mass is 3.0 g;
m₂ = 3.0 g
The volume of the gas at 0.75 mol is determined using ideal gas law;
PV = nRT
Therefore, the volume occupied by 3.0 g of the gas is 16.8 L.
Answer:
.0924 moles of NaCl
Explanation:
So you know you have 5.4 g of NaCl and you need to know how many moles there are in this amount of NaCl
- You'll need to find the atomic mass of the compound NaCl to help you solve for moles
- Sodium (Na) on the periodic table has a mass of 22.99
- Chlorine (Cl) on the periodic table has a mass of 35.45
Add these two together----> 22.99 + 35.45 = 58.44
Now you can calculate for moles
<u>Written-out method:</u>
<u>5.4 grams of NaCl | 1 mole of NaCl </u>
| 58.44 grams NaCl = .0924 moles of NaCl
<u>Plug into calculator method:</u>
(5.4 g of NaCl/ 58.44g NaCl= .0925 moles)
The answer would be 2+ since the atomic number represents how many protons are in the element. In this case, there are 16 protons, but only 14 electrons, which means there are an additional 2 protons, hence the 2+ charge on the ion.
The volume of the gas that occupy at STP is 165. 28 cm^3
calculation
by use of combined gas law that is P1V1/T1=P2V2/T2, where
P1=84.6 kpa
T1=23.5 +273=296.5 K
V1=215 cm^3
At STP T= 273 K and P= 101.325 Kpa
therefore p2 = 101.325 Kpa and T2 = 272 K V2=?
by making V2 the subject of the formula V2 =T2P1V1/P2T1
V2 = 273 K x 84.6 Kpa x 215 cm^3/ 101,.325 Kpa x296.5 K =165.28 cm^3
