Answer: The correct option is 2.
Explanation: Group 15 elements are Nitrogen, phosphorous, Arsenic, Antimony, Bismuth.
To know whether an element exits as a diatomic molecule or not, we look at the atomicity of an element.
Atomicity is the number of atoms of an element combining to form a molecule.
Atomicity of Nitrogen = 2
Atomicity of Phosphorous = 4
Atomicity of Bismuth = 1
Atomicity of Arsenic = 1
The element having atomicity 2 will exist as a diatomic molecule.
Hence, Nitrogen is a diatomic molecule 
Answer:
The value of the heat capacity of the Calorimeter 
= 54.4 
Explanation:
Given data
Heat added Q = 4.168 KJ = 4168 J
Mass of water 
= 75.40 gm
Temperature change = ΔT = 35.82 - 24.58 = 11.24 ° c
From the given condition
Q = 
ΔT + ΔT
Put all the values in above equation we get
4168 = 75.70 × 4.18 × 11.24 + × 11.24
611.37 = × 11.24
= 54.4
This is the value of the heat capacity of the Calorimeter.
A mixture consists of numerous substances, whereas a substance does not consist of mixtures, but rather of compounds. Mixtures can be separated physically, while substances cannot.
47% yield.
First, let's determine how many moles of ethane was used and how many moles of CO2 produced. Start with the respective atomic weights.
Atomic weight carbon = 12.0107
Atomic weight hydrogen = 1.00794
Atomic weight oxygen = 15.999
Molar mass C2H6 = 2 * 12.0107 + 6 * 1.00794 = 30.06904 g/mol
Molar mass CO2 = 12.0107 + 2 * 15.999 = 44.0087 g/mol
Moles C2H6 = 8 g / 30.06904 g/mol = 0.266054387 mol
Moles CO2 = 11 g / 44.0087 g/mol = 0.249950578 mol
Looking at the balanced equation, for every 2 moles of C2H6 consumed, 4 moles of CO2 should be produced. So at 100% yield, we should have 0.266054387 / 2 * 4 = 0.532108774 moles of CO2. But we only have 0.249950578 moles, or 0.249950578 / 0.532108774 = 0.46973587 =
46.973587% of what was expected.
Rounding to 2 significant figures gives 47% yield.
