Test: Some Basic Concepts Of Chemistry - NEET MCQ

Physical properties are those which can be measured or observed without changing the identity or composition of the substance.

The calculation of molar mass involves summing the contributions from each element in the compound. In this case, the molar mass is calculated as follows:

• Element 1: 2 atoms of element with atomic mass 27
• Element 2: 3 atoms of element with atomic mass 16

The calculation can be broken down into the following steps:

• Calculate contribution from the first element: 2 × 27 = 54
• Calculate contribution from the second element: 3 × 16 = 48

Now, add these contributions together:

• Total Molar Mass: 54 + 48 = 102 g/mol

Thus, the molar mass of the compound is 102 g/mol.

The SI units for the base physical quantities are as follows:

• Length: Meter (m) is the SI unit.
• Mass: Kilogram (kg) is the SI unit.
• Current: Ampere (A) is the SI unit.

Option A correctly lists Meter, Kilogram, and Ampere, which are the correct SI units for length, mass, and current, respectively.

Molarity is defined as the number of moles of solute present per litre of solution. This means that for any given solution, its molarity is calculated by:

• Dividing the number of moles of the solute by the volume of the solution in litres.

Therefore, the correct answer is option C.

Moles of CO =8 moles Moles of Fe₂O₃= 2.5 moles.

3 moles of CO is needed for 1 mole of Fe₂O₃ so 8 moles of CO will require 2.66 mole of Fe₂O₃ so Fe₂O₃ is limiting reagent.

1 mole of Fe₂O₃ produce 2 mole of Fe so 2.5 mole of Fe₂O₃will produce 5 mole of Fe = 280g of Fe.

Also 1 mole of Fe₂O₃ also produce 3 mole of CO₂ so 2.5 mole of Fe₂O₃ will produce 7.5 mole of CO₂=330g.

According to this total mass of reactants = total mass of product so no. of atoms of each element in reactant is equal to no. of atoms of that element in product

The molar mass is calculated by summing the atomic masses of each element:

• Carbon (C): 6 atoms × 12 g/mol = 72 g/mol
• Hydrogen (H): 10 atoms × 1 g/mol = 10 g/mol
• Oxygen (O): 5 atoms × 16 g/mol = 80 g/mol

Total molar mass = 72 + 10 + 80 = 162 g/mol.

C-0/100-0 = F-32/180.
C/5= F-32/9.
C/5= 100-32/9.
C/5= 68/9.
C= 68×5/9.
C= 340/9.
C= 37.77.
C= 37.8

Density = mass/volume. SI unit of mass is kg and that of volume is m³ so SI unit of Density is kg m⁻³

The calculation of masses (sometimes volumes also) of the reactants and the products involved in a chemical reaction is called stoichiometry.

The molar mass of CaCO₃ is calculated as follows:

• Molar mass = (1 × 40 g/mol)
• + (1 × 12 g/mol)
• + (3 × 16 g/mol)

This results in:

• Molar mass = 100 g/mol

Since we know that 1litre -1000ml 1ml-1\1000litre So,12ml-1/1000×12=12/1000 =0.012

The Kelvin scale is an absolute temperature scale where 0 K corresponds to absolute zero, the coldest possible temperature.

To convert a temperature from Celsius to Kelvin, you add 273.15 to the Celsius temperature. Thus, the relationship between the Kelvin (K) and Celsius (°C) scales is given by the formula:

K = °C + 273.15

This conversion accounts for the offset between the two scales, ensuring that the temperature in Kelvin accurately reflects the absolute temperature.

The molecular mass of glucose (C₆H₁₂O₆) is calculated by adding the atomic masses of all constituent atoms:

• Carbon (C): 6 atoms × 12 u = 72 u
• Hydrogen (H): 12 atoms × 1 u = 12 u
• Oxygen (O): 6 atoms × 16 u = 96 u

Total molecular mass = 72 u + 12 u + 96 u = 180 u

Molar mass of AgNO₃ = mass of Ag + N + O₃ = 107.87 + 14 + 3* 16 = 107. 87 + 14 + 48 = 169.87 g

Chemical Formula: ZnSO₄

Molar Mass Calculation:

• Zinc (Zn): 65.38 g/mol
• Sulfur (S): 32.07 g/mol
• Oxygen (O₄): 4 × 16.00 g/mol = 64.00 g/mol

Total Molar Mass: 65.38 + 32.07 + 64.00 = 161.45 g/mol

The molar mass of anhydrous ZnSO₄ is approximately 161.47 g/mol.

Standard temperature and pressure (STP) is defined as 0 degrees Celsius and 1 atmosphere of pressure. At STP, 1 mole of any gas occupies 22.4 liters.
First, calculate the number of moles of hydrogen gas (H2) in 67.2 liters:
67.2 L / 22.4 L/mole = 3 moles of H2
Each molecule of H2 contains 2 atoms of hydrogen. Therefore, 3 moles of H2 contains:
3 moles * (6.022 x 10^23 molecules/mole) * 2 atoms/molecule = 3.6132 x 10^24 atoms of hydrogen.

n can vary from 0 to 10 and can be either positive (+ve) or negative (–ve).

Correct option is A
The stock solution is the solution of higher concentration. Therefore in the laboratory, a solution of the desired concentration is prepared by diluting a stock solution.
Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
Hence, option A is correct

18g H₂O = 1mol water = 6.02 x 10²³ molecules of water = 6.02 x 10²³ atoms of oxygen.

Chemistry primarily contributes to developing materials used in superconductivity, but does not play a major role in the theoretical explanation of the phenomenon, which falls under physics. Therefore, chemistry's role is minor in explaining superconductivity itself compared to its involvement in:

• Material synthesis
• Development of superconducting materials

Solid
Holds shape
Fixed Volume


Liquid
Shape of Container
Free Surface
Fixed Volume


Gas
Shape Of Container
Volume of Container

Explanation:

Solid is the only state of matter that has a definite shape and definite volume.

Molality is defined as the number of moles of solute per kilogram of solvent.

• Moles of solute: The quantity of the substance being dissolved.
• Kilograms of solvent: The mass of the substance in which the solute is dissolved.

This means that:

• Molality is a way to express the concentration of a solution.
• It is particularly useful in situations where temperature changes occur, as it does not change with temperature variations.

To convert millilitres to litres, divide by 1000 because 1 litre equals 1000 millilitres. Therefore:

• 0.05 mL divided by 1000 equals 0.00005 litres.