Answer:
The given metal sample is not aluminum because its density is 3.0 g/cm³ while density of aluminum is 2.7 g/cm³.
Explanation:
Given data:
Density of aluminum = 2.7 g/cm³
Mass of metal sample = 52.0 g
Volume of metal sample = 17.1 cm³
which sample is that = ?
Solution:
The given problem will be solve through density formula.
d = m/v
d = density
m = mass
v= volume
Now we will put the values in formula.
d = 52.0 g/ 17.1 cm³
d = 3.0 g/cm³
It is given in question the density of aluminum is 2.7 g/cm³. The given metal sample is not aluminum because its density is 3.0 g/cm³.
Rate of Reaction ca be increased by applying following changes,
1) Increase in Temperature:
Increase in Temperature results in the increase of Kinetic Energy, Hence, velocity of reactants increases and rate of collisions increases. Thus, more reactants colloid with enough energy to change into products in given time.
2) Decrease in Activation Energy:
Activation energy is the minimum amount of energy required by reactants to cross the energy barrier to convert into products. Hence, activation energy is decreased by using catalyst.
3) Concentration of Reactants:
The greater the concentration of reactants, greater is the number of reactants per volume. More reactants in less area increase the probability of collision. Hence, collisions increase and rate of reaction increases.
4) Increasing Surface Area of Reactant:
Greater the surface area greater is the rate of reaction.
Answer: Option (c) is the correct answer.
Explanation:
According to the Born-Lande equation,
E = 
where, 
= Avogadro's constant
r = distance between the anion and cation
M = Medlung constant
= charge on the cation
= charge on the anion
E = lattice energy
According to this expression, lattice energy is inversely proportional to the distance between the cation and anion. And, when we move down a group then there occurs an increase in the atomic radii of the atoms.
As a result, there will occur a decrease in their lattice energy. Since, the anionic part is same in all the given species but the cationic part is different.
In 
the size of magnesium cation is smaller than calcium, barium and strontium ion. Hence, there will be least distance between Mg and Br ions.
Thus, we can conclude that the magnitude of lattice energy will be the highest in .
(~26grams/mole) and Avogadros # (6.022x10^23) 84.3grams x 1mole/26grams x 6.022x10^23 molecules/mole = 1.95x10^24 molecules of C2H2
The number of electrons is 20. hope this helps
