Answer:
Some of the physical changes used by the industrial chemist in order to identify it is by scratching it with other metals in order to find the hardness of it. Trying to deform it in order to find the malleability, and to heat it and measure the temperature in order to find the melting point.
Some of the chemical changes used by the industrial chemist in order to identify it is by inserting it in water to observe that whether it reacts with it or not, if the reaction is violent, then the metal belongs to either group I or group II. The other method is to insert it in acids of distinct strength and to observe its reaction. The metals belonging to the second group react briskly with acids. The other metals react gradually with acids and others are almost inert.
Answer:
n₂ = 2.55 mol
Explanation:
Given data:
Initial number of moles = 0.758 mol
Initial volume = 80.6 L
Final volume = 270.9 L
Final number of moles = ?
Solution:
Formula:
V₁/n₁ = V₂/n₂
V₁ = Initial volume
n₁ = initial number of moles
V₂ = Final volume
n₂ = Final number of moles
now we will put the values in formula.
V₁/n₁ = V₂/n₂
80.6 L / 0.758 mol = 270.9 L/ n₂
n₂ = 270.9 L× 0.758 mol / 80.6 L
n₂ = 205.34 L.mol /80.6 L
n₂ = 2.55 mol
Na₂CrO₄ + PbCl₂ → PbCrO₄ + 2 NaCl
<u>Explanation:</u>
In a double displacement reaction, the reactants which are involved in the reaction exchanging their ions thereby produces 2 new compounds. Here sodium chromate and lead chloride are undergoing double displacement reaction, the ions exchanges their position there by forming sodium chloride and lead chromate. So the double displacement reaction is given as,
Na₂CrO₄ + PbCl₂ → PbCrO₄ + 2 NaCl
<u>Answer 2 :</u> The given electronic configuration for a neutral atom of phosphorous in its ground state is incorrect.
Explanation :
A neutral atom of phosphorous has 15 electrons.
The given electronic configuration is incorrect.
The reason is, According to Aufbau principle, the electrons will be first filled in the sub-shell having lower orbital energy. As from the given configuration, 3p sub-shell has lower orbital energy than 4s sub-shell. So, the electrons will be filled in 3p sub-shell first. Hence, the ground state electronic configuration of neutral atom of phosphorous is,
<u>Answer 3 :</u>
Element Rubidium Magnesium Aluminium
Symbol Rb Mg Al
Group number 1 2 13
Number of valence 1 2 3
electrons
The order of general reactivity on the basis of number of valence electrons.
Rb > Mg > Al
Reason : The reactivity is determined by the number of electrons present in the outermost shell that means the element which have 1 valence electron will be more reactive because they can easily lose electrons.
I had the same question last week and my answer was C. Try that.
