C . oxygen
i had this the other day
<span>1. MgBr2
Soluble.
Rule: all the binary compounds of the group 17 (different to F) with metals are solubles, except those formed with Ag, Hg (I) and Pb.
2. PbI2
Insoluble.
Rule: it is one of the exceptions stated in the rule above.
3. (NH4)2CO3
Soluble.
Rule: salts containing NH4(+) are soluble.
4. ZnSO4
Soluble
Rule: </span><span>This salt is not an exception to the rule that most sulfate salts are soluble. Important exceptions to this rule include BaSO4,
PbSO4, Ag2SO4 and SrSO4
5. Sr(OH)2
Soluble (slightly soluble).
Rule: </span><span>Hydroxide salts of Group II elements (Ca,
Sr, and Ba) are slightly soluble</span>
They start with the numbers u need to know in order to slove the problem and there has to be a story behind it
<u>Answer:</u> The density of substance is 
<u>Explanation:</u>
To calculate density of a substance, we use the equation:

We are given:
Mass of substance = 61.6 g
Volume of substance = 
Putting values in above equation, we get:

Hence, the density of substance is 
<u> There are more total ions in 2.2 moles of </u>
<h3>What are ions?</h3>
Ion, any atom or group of atoms that bears one or more positive or negative electrical charges. Positively charged ions are called cations; negatively charged ions, anions.
Ions are formed by the addition of electrons to, or the removal of electrons from, neutral atoms or molecules or other ions; by combination of ions with other particles; or by rupture of a covalent bond between two atoms in such a way that both of the electrons of the bond are left in association with one of the formerly bonded atoms.
Examples of these processes include the reaction of a sodium atom with a chlorine atom to form a sodium cation and a chloride anion; the addition of a hydrogen cation to an ammonia molecule to form an ammonium cation; and the dissociation of a water molecule to form a hydrogen cation and a hydroxide anion.
Learn more about ions
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