False, that only applies to water as far as I know, but I know for a fact that gold does not melt at 0 degrees Celsius
Protons
Explanation: the atomic number is the same as the number of protons
The options for given question are as follow,
1) Methane molecules show hydrogen bonding.
<span>2) Ammonia molecules show hydrogen bonding. </span>
<span>3) Methane has stronger hydrogen bonding than ammonia. </span>
<span>4) Both the compounds do not show hydrogen bonding. </span>
<span>5) Both the compounds have strong hydrogen bonding.
</span>
Answer:
Correct answer is Option-2 (Ammonia molecules show hydrogen bonding).
Explanation:
Hydrogen bond interactions are formed when a partial positive hydrogen atom attached to most electronegative atom of one molecule interacts with the partial negative most electronegative element of another molecule. So, in Ammonia hydrogen gets partial positive charge as nitrogen is highly electronegative. While the C-H bond in Methane is non-polar and fails to form hydrogen bond interactions.
Answer:
Covalent compounds have weak forces of attraction between the binding molecules. Thus less energy is required to break the force of bonding. Therefore covalent compounds have low melting and boiling point.
Explanation:
Answer: 72 grams of 
are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number 
of particles.
To calculate the number of moles, we use the equation:
Putting in the values we get:
According to stoichiometry:
1 mole of 
requires 5 moles of oxygen
0.45 moles of require= 
moles of oxygen
Mass of 
72 grams of are needed to completely burn 19.7 g
