A science is an intellectual study of the natural world through experimentation and observation. It seeks to answer objective questions about natural phenomenon which can be quantified and measured, and does not seek to answer philosophical, ideological, or otherwise subjective questions.
C)
Explanations
Approach A: Comparison of the bonding atoms
What element(s) does each species comprise?
- carbon monoxide- one metalloid, carbon, bonded to one nonmetal
- oxygen- one nonmetal
- lithium bromide- one metal and one nonmetal
- ammonia- two nonmetals
Lithium bromide is the only substance that features a metal element bonded to a nonmetal element among all four species in the list. It takes significant differences in electronegativity for the bonding atoms in a binary compound to ionize and form an ionic compound. Therefore the species in question shall contain at least one metal element bonded to one nonmetal.
Approach B: Comparison of melting points
Recall the physical state of the species under room temperature and pressure:
- carbon monoxide- gas
- oxygen- gas
- lithium bromide- ?
- ammonia- gas
Ionic bonds hold ions in an ionic compound in place with great degrees of rigidity. In contrast, covalent molecules adhere to each other with intermolecular interactions that are weaker by magnitudes. It's unlikely for ionic crystals to behave as gases under standard conditions. Thus A, B, D cannot be ionic compounds.
Answer:
True.
Explanation:
ΔHfusion value is defined as the amount of energy needed to produce a phase change in 1 mole of substance at constant pressure, specifically from solid to liquid. Let´s imagine two random substances A and B, with ΔHfusionA= 100 J/mol and ΔHfusionB=200J/mol. If we apply 150J of energy in 1 mol of each substance, we have enough energy for melt A, but we still need 50J for melt B. For that reason a low value of ΔHfusion means is easier to convert it from solid to liquid.