Answer:
B. 1:2
Explanation:
Molar ratio depicts the relationship between the number of moles of two substances. The chemical equation in this question is as follows:
2H2 + O2 → 2H2O
This question is asking to identify the molar ratio of O2 to H2O in the equation. Since 1 mole of oxygen gas (O2) produces 2 moles of water (H2O). Hence, the O2 to H2O molar ratio is 1:2.
Answer:
This metal could be the aluminium with a specific heat of 
Explanation:
A pie of unknown metal presents a mass (M) of 348 g. This metal is heated using energy (E) of 6.64 kJ and the temperature increases from T1 =24.4 to T2 =43.6°C. We can calculate the specific heat (H) of this metal as follows

We can replace previously presented data in this equation. After simplifying and converting to adequated units, we found that

Finally, the specific heat of this metal is

The aluminium could be the metal, its specific heat is similar to that found in this problem.
Finally, we can conclude that this metal could be the aluminium with a specific heat of 
<span>it tells you the sequence in which events occurred, not how long ago they occurred.</span>
1st one is Science and the 2nd one is Bias
Boiling point of a compound is determined by the strength of intermolecular forces of attraction between the molecules present in it. Stronger the intermolecular forces of attraction, higher will be the boiling point.
Ionic compounds show ion-ion interactions which are the strongest among all. Ion-dipole interactions are shown when ionic solutes are dissolved in polar solvents. Hydrogen bonding is also a relatively stronger force that is present between H atom and an electronegative atom like F, O and N(
) . All polar molecules show dipole-dipole interaction (
and
). Dispersion forces are the weakest intermolecular forces due to momentary dipoles between electron clouds and nucleus.
Among the given compounds,
has dispersion forces as the major intermolecular forces of attraction. So they they exhibit the weakest IMF, hence have the lowest boiling point.