Answer:
A coordinate covalent bond is a bond in which both electrons come from the same atom.
Example: The bonding between the C atom and the O atom (carbon monoxide)
Answer:
Oxygen, and from solid to liquid. This is because oxygen's melting point is at -218°C. Melting point refers to the temperature where heat causes particles to vibrate with sufficient energy to break the solid structure, so for oxygen this means it's being turned into a liquid.
Answer:
The vertical columns (group) of the periodic table are arranged such that all it's elements have the same number of valence electrons. All elements within a certain group thus group share similar properties.
Answer:
21.3 g. Option B
Explanation:
The reaction is:
4HF(g) + SiO₂(s) → SiF₄(g) + 2H₂O(g)
We analysed it and it is correctly balanced.
4 moles of hydrogen fluoride react to 1 mol of silicon dioxide in order to produce 1 mol of silicon fluoride and 2 moles of water vapor.
We determine molar mass of each reactant:
HF → 1.01 g/mol + 19 g/mol = 20.01 g/mol
SiO₂ → 16 g/mol . 2 + 28.09 g/mol = 60.09 g/mol
We convert mass to moles: 16 g . 1 mol /60.09g = 0.266 moles of glass
Ratio is 1:4. 1 mol of glass react to 4 moles of HF
Our 0.266 moles may react to (0.266 . 4) / 1 = 1.07 moles of gas
We convert moles to mass: 1.07 mol . 20.01 g/mol = 21.3 g
