Answer:
used=Evaporation and sublimation
released=condensation and freezing
Explanation:
Answer:
0.302 moles
Explanation:
Data given
Mass of Pb(NO₃)₂ = 100 g
Moles of Pb(NO₃)₂ = ?
Solution:
To find mole we have to know about molar mass of Pb(NO₃)₂
So,
Molar mass of Pb(NO₃)₂ = 207 + 2[14 + 3(16)]
= 207 + 2[14 + 48]
= 207 + 124
Molar mass of Pb(NO₃)₂ = 331 g/mol
Formula used :
no. of moles = mass in grams / molar mass
Put values in above formula
no. of moles = 100 g / 331 g/mol
no. of moles = 0.302 moles
no. of moles of Pb(NO₃)₂ = 0.302 moles
The amount of heat needed to raise the temperature of an object is obtained through the equation,
H = m(cp)(20) + m (heat of fusion) + m(cp) (dT)
where H is heat, m is mass, cp is specific gravity, and dT is the change in temperature. The specific gravity of water is 0.5 cal/g.C. The third term is for water and cp is equal to 1 cal/g.C. Substituting the values,
815 cal = (5 g)(0.5 cal/g.C)(20C) + (80 cal/g)(5 g) + 5(1)(T2)
The value of T2 is 73 degrees C.
Answer: K and Mg
Explanation:
The first one refers to the atomic radius and increases going down and to the left on the periodic table. K is in between Rb and Na.
