An element that exist as a discreet atom has only one atom which can stand alone on its own. Example of this is Neon, which is a noble gas. The chemical symbol for neon is Ne.
Elements are able to exist as discreet atom because they are chemical stable and inert.
The second one.
Remember, temperature is the AVERAGE kinetic energy. So, looking for highest average kinetic energy means looking for highest temperature, which is 55.
Note: the amount of the substance does not determine the average kinetic energy.
Answer:
−2399.33 kJ
Explanation:
If NH₄NO₃ reacts with fuel oil to give a ΔH of -7198 for every 3 moles of NH₄NO₃
What is the enthalpy change for 1.0 mole of NH₄NO₃ in this reaction
∴ For every 1 mole, we will have 
of the total enthaply of the 3 moles
so, to determine the 1 mole; we have:
= −2399.33 kJ
∴ the enthalpy change for 1.0 mole of NH₄NO₃ in this reaction = −2399.33 kJ
Answer:
C)We cannot be sure unless we find out its boiling point.
Explanation:
It is necessary to clearly explain here that simply observing two compounds of the same homologous series irrespective of how close they may be in the series will not give us the faintest idea regarding which one will be a liquid, solid or gas at room temperature.
However, to determine whether an unknown substance will be a liquid at room temperature, then its important to measure its boiling point. If the boiling point is above room temperature, and the melting point is below room temperature, the compound is a liquid. If the boiling point of the unknown substance is below room temperature, it is a gas.
It is now safe to conclude that cannot decide on the state of matter in which a compound exists unless we know something about its boiling point, not merely looking closely at the properties of its neighbouring compounds in the same homologous series
