Answer:- 
molecules.
Solution:- The grams of tetrabromomethane are given and it asks to calculate the number of molecules.
It is a two step unit conversion problem. In the first step, grams are converted to moles on dividing the grams by molar mass.
In second step, the moles are converted to molecules on multiplying by Avogadro number.
Molar mass of 
= 12+4(79.9) = 331.6 g per mol
let's make the set up using dimensional analysis:
= molecules
So, there will be molecules in 250 grams of .
The molarity of acetic acid in the vinegar is 0.94 M
<u><em> calculation</em></u>
Step 1: write the balanced equation between CH3COOH + NaOH
that is CH3COOH + NaOH → CH3COONa + H2O
step 2 : find the moles of NaOH
moles =molarity x volume in L
volume in liters = 26.90/1000=0.0269 l
moles = 0.175 mol /L x 0.0269 L =0.0047 moles of NaOH
Step 3: use the mole ratio to find moles of CH3COOH
that is the mole ratio of CH3COOH: NaOH is 1:1 therefore the moles of CH3COOH is =0.0047 moles
Step 4: find the molarity of CH3COOH
molarity = moles/volume in liters
volume in liter = 5.00/1000 =0.005 l
molarity is therefore=0.0047 moles/ 0.005 l = 0.94 M
The answer:
<span>The equation of its dissolution in water is: AgNO3 → Ag + (aq) + NO3- (aq)
and </span>AgNO3 → Ag + (aq) + NO3- (aq)
1 mol 1mol 1mol
? -------- 0.854mo
so for finding the value, it is sufficients to complute 1 x 0.854 mol =0.854 mol
so, 0.854 mol is required for the reaction to form 0.854 mol of Ag
Answer :Solid in bottle a is ionic, solid in bottle b is molecular and solid in bottle c is ionic.
Explanation :
Ionic compound is formed when a metal atom donates one or more electrons to a non metal. This results in the formation of a cation ( a positive ion) and an anion ( a negative ion). These ions are bonded to each other by electrostatic attraction.
The intermolecular forces in case of a an ionic compound are very strong.
The melting point of a substance depends on how strongly the molecules are attracted to each other. Stronger the forces, higher is the melting point.
Therefore ionic compounds always have very high melting points.
On the other hand, covalent compounds have weak intermolecular forces. Therefore they have low melting points.
Based on above discussion, we can classify the given compounds as follows.
a) Solid in bottle a is Ionic as it has high melting point.
b) Solid in bottle b is molecular as it has low melting point.
c) Solid in bottle c is Ionic as it has high melting point.
Ionic salt dissociate completely in water particularly in water at low concentration.
The molal freezing point of depression constant for water is 1.85kg/k/mol
therefore depression of freezing point =1.853 x 0.100 x 2.32=0.429 degrees celsius
hence solute freeze at - 0.429 degree celsius
