Lewis diagram:
well first you have to know the Valence electrons the elements which will on top of the periodic table.
for examples:
H2O
it will be O-H-O and the dots will on top. oxygen have 6 valence electrons so that mean it need 6 dots. also for H it will have 7 V-electrons.
Answer
For this we use ideal gas equation which is:
P1V1 = P2V2
P1 = 1.10 atm
V1 = 326 ml
P2 = 1.90
V2 = ?
By rearranging the ideal gas equation:
V2 = P1V1 ÷ P2
V2 = 1.10 × 326 ÷1.90
V2 = 358.6 ÷ 1.90
V2 = 188.7 ml
Answer:

Explanation:
In a nuclear reaction, the total mass and total atomic number remains the same.
Am has an atomic number of 95. So correct reaction is:-
To calculate A:
Total mass on reactant side = total mass on product side
343 + 4 = A + 2
A = 345
To calculate Z:
Total atomic number on reactant side = total atomic number on product side
95 + 2 = Z + 0
Z = 97
Hence, the isotopic symbol of unknown element is 
Answer:
The enthalpy change in the the reaction is -47.014 kJ/mol.
Explanation:

Volume of water in calorimeter = 22.0 mL
Density of water = 1.00 g/mL
Mass of the water in calorimeter = m

Mass of substance X = 2.50 g
Mass of the solution = M = 2.50 g + 22 g = 24.50 g
Heat released during the reaction be Q
Change in temperature =ΔT = 28.0°C - 14.0°C = 14.0°C
Specific heat of the solution is equal to that of water :
c = 4.18J/(g°C)


Heat released during the reaction is equal to the heat absorbed by the water or solution.
Heat released during the reaction =-1.433 kJ
Moles of substance X= 
The enthalpy change, ΔH, for this reaction per mole of X:
