Answer:
- <em>Hydration number:</em> 4
Explanation:
<u>1) Mass of water in the hydrated compound</u>
Mass of water = Mass of the hydrated sample - mass of the dehydrated compound
Mass of water = 30.7 g - 22.9 g = 7.8 g
<u>2) Number of moles of water</u>
- Number of moles = mass in grams / molar mass
- molar mass of H₂O = 2×1.008 g/mol + 15.999 g*mol = 18.015 g/mol
- Number of moles of H₂O = 7.9 g / 18.015 g/mol = 0.439 mol
<u>3) Number of moles of Strontium nitrate dehydrated, Sr (NO₃)₂</u>
- The mass of strontium nitrate dehydrated is the constant mass obtained after heating = 22.9 g
- Molar mass of Sr (NO₃)₂ : 211.63 g/mol (you can obtain it from a internet or calculate using the atomic masses of each element from a periodic table).
- Number of moles of Sr (NO₃)₂ = 22.9 g / 211.63 g/mol = 0.108 mol
<u>4) Ratio</u>
- 0.439 mol H₂O / 0.108 mol Sr(NO₃)₂ ≈ 4 mol H₂O : 1 mol Sr (NO₃)₂
Which means that the hydration number is 4.
Answer:
2.173 moles of ethanol is presented in a 100.0g sample of ethanol .
Explanation:
The amount of substance that contains as many Particles as there are atoms in exactly 12g of carbon- '12 isotope is called 1 mole '= 46 u.
Answer:
174 kPa
Explanation:
Given that,
Initial temperature, T₁ = 25° C = 25+273 = 298 K
Final temperature, T₂ = 225°C = 225 + 273 = 498 K
Initial pressure, P₁ = 104 kPa
We need to find the new pressure. The relation between the temperature and pressure is given by :
So,
or
P₂ = 174 kPa
So, the new pressure is 174 kPa.
First, let us define Electronegativity. Electronegativity is "the ability of an atom to attract electrons." In addition, electronegativity increases in elements from left to right, while on the other hand, electronegativity decreases from top to bottom in an element group. It decreases because the atomic radius increases as we go downward an element in the group.
