Answer:
Option-A is the correct answer
Explanation:
Lithium belong to group 1 metals. Hence, it can loose one electron to form lithium ion i.e. Li⁺¹ or Li⁺
While, Nitrogen is non-metal and hence has the ability to gain the electron lost by lithium metal. Furthermore, Nitrogen can gain maximum 3 electrons to acheive noble gas configuration. Hence, three Li atoms will loose their electrons and Nitrogen will gain those three electrons to form nitride ion i.e. N³⁻.
Answer:
A group is a column of elements in the periodic table of the chemical elements.
So, the columns on the periodic table are called groups.
The energy can be shown as:
Q = ms dT
Whereas, m is the mass of block
s is specific heat
dT is change in temperature.
Copper block having the lowest specific heat and thus having the higher change in temperature and therefore having the higher final temperature.
Answer : The correct option is, (D) 3600 kJ
Explanation :
Mass of octane = 75 g
Molar mass of octane = 114.23 g/mole
Enthalpy of combustion = -5500 kJ/mol
First we have to calculate the moles of octane.

Now we have to calculate the heat released in the reaction.
As, 1 mole of octane released heat = -5500 kJ
So, 0.656 mole of octane released heat = 0.656 × (-5500 kJ)
= -3608 kJ
≈ -3600 kJ
Therefore, the heat released in the reaction is 3600 kJ
Answer:
1.99 x 10⁻¹⁸J
Explanation:
Given parameters:
Frequency of the wave = 3 x 10¹⁵Hz
Unknown:
Energy of the photon = ?
Solution:
To solve this problem, we use the expression below;
E = hf
Where E is the energy, h is the Planck's constant and f is the frequency
Now insert the parameters and solve for E;
E = 6.63 x 10⁻³⁴ x 3 x 10¹⁵ = 19.9 x 10⁻¹⁹J or 1.99 x 10⁻¹⁸J