Answer:
Calcium
Explanation:
The symbol for the element with a mass number of 27 is actually Al for Aluminum instead of Co for Cobalt. Mass number refers to atomic mass, not atomic number.
Aluminum has an atomic mass of 26.982 or 27.
The letters to unscramble are I, M, C, Al, U, and C.
The mystery element is Calcium.
Hope that helps.
C) ![\text{LiBr}_{3}](https://tex.z-dn.net/?f=%5Ctext%7BLiBr%7D_%7B3%7D)
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:
B) ΔT = Q/mCp
Explanation:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.Cp. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
Cp = specific heat capacity of substance
ΔT = change in temperature
ΔT = Final temperature - initial temperature
The substances with higher value of specific heat capacity require more heat to raise the temperature by one degree as compared the substances having low value of specific heat capacity.For example,
The specific heat capacity of oil is 1.57 j/g. K and for water is 4.18 j/g.K. So, water take a time to increase its temperature by one degree by absorbing more heat while oil will heat up faster by absorbing less amount of heat.
A pure substance and a element