Answer:
Conduct Electricity and Are malleable
Explanation:
Answer:

Explanation:
1. Mass of zinc
The density of zinc is 7.14 g/cm³
D = m/V

2. Volume of aluminium
The density of aluminium is 2.60/cm³.

Answer: option A. Cobalt
Explanation:
1) Data:
Q = 1.24 × 10⁶ J
m = 2 kg
Tf = 1768 K
Ti = 298 K
Cs = ?
2) Formula:
Q = m Cs ΔT
ΔT = Tf - Ti = 1,768K - 298K = 1,470K
3) Calculations:
i) Solve for Cs:
Cs = Q / [ m ΔT]
ii) Substitute the data:
Cs = 1.24 × 10⁵ J / [ 2kg (1768K - 298K) ] = 421 J / (kg K)
4) Compare with the specific heats (Cs) of the vaious metals given and you find that it is Cobalt.
Answer : The molality of NaCl is, 1.95 mol/kg
Explanation :
Formula used for Elevation in boiling point :

where,
= change in boiling point = 
= boiling point constant for water = 
m = molality
i = Van't Hoff factor = 2 (for electrolyte)
The dissociation
will be,

So, Van't Hoff factor = Number of solute particles =
= 1 + 1 = 2
Now put all the given values in the above formula, we get:


Therefore, the molality of NaCl is, 1.95 mol/kg