Answer:
Compounds are pure substance consisting of two or more different atoms
Answer: C) Roman numeral following the name.
Explanation: If we want to name an ionic compound like NaCl then we can easily write its name. Na is sodium and Cl is chlorine. First we write the name of the metal ion and then the name of the anion it has. Here we have mono atomic ion and for these we use the suffix -ide. So, the name will be sodium chloride.
Now, if we have something like 
and we write the name as Iron chloride, then it will not be correct since Fe is a transition metal and it shows +2 and +3 oxidation states. So, to overcome this difficulty, a roman numeral is used for the oxidation state of the metal ion. The name of above compound will be Iron(III)chloride. Similarly, if we have 
then its name will be written as Iron(II)chloride.
In both the above names, the roman numerals (III) and (II) are indicating numerical value of the charge of the metal ion. So, the correct choice is C) Roman numerals following the name.
when naming a transition metal ion that can have more than one common ionic charge, the numerical value of the charge can be indicated by a Roman numeral following the name.
D, the energy of formation is equal to the dissociation. so from magnesium ions and Hydrogen ions, when they form the lattice energy is equal to formation-dissociation, as they aren't going to dissociate (fixed in lattice) the formation should be the same as the the overall lattice energy.
Answer:
<em>Barometers measure this pressure. ... Changes in the atmosphere, including changes in air pressure, affect the weather. Meteorologists use barometers to predict short-term changes in the weather. A rapid drop in atmospheric pressure means that a low-pressure system is arriving.</em>
Explanation:
<h3>
<em>I </em><em>hope</em><em> this</em><em> helps</em><em>!</em></h3>
Answer:
See the explanation and examples below, please.
Explanation:
To calculate the molar mass of a substance you must have the atomic weights of each component:
Example NaCl ionic compound (sodium chloride, known as table salt)
Molar mass NaCl = Atomic weight Na + Atomic weight Cl = 22, 98 gr + 35, 45gr = 58.35 grams / mol
Example covalent compound HCl (hydrochloric acid) = Atomic weight H + Atomic weight Cl = 1, 004gr + 35, 45 gr = 36, 45 grams / mol
In the case of having compound H20 (water), it is calculated:
Molar mass NaCl = 2 x (Atomic weight H) + Atomic weight 0 (the atomic weight of 1 mol of Hydrogen is multiplied by 2)
