<span>From the above given choices :
melting is an endothermic process</span>
Answer:
Ar
Explanation:
does not react with anything it has a full electron shell so it does not combine and it is a noble gas
Answer:
zero
Explanation:
I I think one should be so accurate with measurements and experiments
Explanation:
As 
is a covalent compound because it is made up by the combination of two non-metal atoms. Atomic number of an iodine atom is 53 and it contains 7 valence electrons as it belongs to group 17 of the periodic table.
Therefore, sharing of electrons will take place when two iodine atoms chemically combine with each other leading to the formation of a covalent bonding.
Hence, weak forces like london dispersion forces will be present between a molecule of .
The weak intermolecular forces which can arise either between nucleus and electrons or between electron-electron are known as dispersion forces. These forces are also known as London dispersion forces and these are temporary in nature.
thus, we can conclude that london dispersion force is the major attractive force that exists among different molecules in the solid.
Answer:
The answer to your question is below
Explanation:
Data
mass of CaCO₃ = 155 g
mass of HCl = 250 g
mass of CaCl₂ = 142 g
reactants = CaCO₃ + HCl
products = CaCl₂ + CO₂ + H₂O
1.- Balanced chemical reaction
CaCO₃ + 2HCl ⇒ CaCl₂ + CO₂ + H₂O
2.- Limiting reactant
molar mass of CaCO₃ = 40 + 12 + 48 = 100 g
molar mass of HCl = 2[1 + 35.5 ] = 73 g
theoretical proportion CaCO₃ /HCl = 100 / 73 = 1.37
experimental proportion CaCO₃ /HCl = 155 / 250 = 0.62
As the experimental proportion was lower than the theoretical proportion the limiting reactant is CaCO₃
3.-
Calculate the molar mass of CaCl₂
CaCl₂ = 40 + 71 = 111 g
100 g of CaCO₃ ------------------ 111 g of CaCl₂
155 g of CaCO₃ ----------------- x
x = (155 x 111) / 100
x = 17205 / 100
x = 172.05 g of CaCl₂
4.- percent yield
Percent yield = 142 / 172.05 x 100 = 82.5 %
5.- Excess reactant
100 g of CaCO₃ -------------------- 73 g of HCl
155 g of caCO₃ ------------------- x
x = (155 x 73)/100
x = 133.15 g
Mass of HCl = 250 - 133.15
= 136.9 g
