Graphite is used as a dry lubricant due to the presence of
mobile electrons
free electrons
octahedral structures
layered structures
Correct answer is D
Graphite is an excellent dry lubricant. This is because its layered structure allows one layer to slide over another easily. It is non-volatile and not sticky.
1.0 atm
0.1 atm
9.0 atm
0.9 atm
Correct answer is B
Partial pressure is found by Dalton's Law:
Px = PTotal ( nx / nTotal )
where
Px = partial pressure of gas x
PTotal = total pressure of all gases
nx = number of moles of gas x
nTotal = number of moles of all gases
Step 1
Find PTotal
Standard pressure is 1 atm.
Step 2
Add up the number of moles of the component gases to find nTotal
nTotal = noxygen + nnitrogen
nTotal = 100 + 900
nTotal =1000cm3
Step 3
Now you have all the information needed to plug the values into the equation and solve for Poxygen
P-oxygen = PTotal ( n-oxygen / nTotal )
oxygen = 1 atm ( 100 / 1000 )
oxygen= 0.1atm
Which of the following acids would form normal salt only?
Tetraoxosulphate(VI) acid
Trioxonitrate(V) acid
Tetraoxophosphate(V) acid
Trioxosulphate(IV) acid
Correct answer is A
Normal salts are formed when all the replaceable hydrogen ions in the acid have been completely replaced by metallic ions
Consider the following reaction equation:
CaO + SiO2 ------> CaSiO3
Silicon(IV) oxide is acting as
a basic oxide
a reducing agent
an acidic oxide
an oxidizing agent
Correct answer is C
Silicon dioxide is an acidic oxide. It will react with strong bases to form silicate salts, SiO2 is acidic oxide because Si is non-metal. Oxides of non-metals are acidic in nature.
Before a reaction could take place, there should be
ionization of reactant particles
breakage of bonds of products
breakage of bonds of reactants
ionization of product particles
Correct answer is C
Activation energy must be achieved before reaction begin. This is because in any chemical reaction, chemical bonds in the reactants are broken, and new bonds in the products are formed