All questions
- M.In two moles of acetaldehyde (CH3 CHO) calculate the following a. Number of moles of carbon b. Number of moles of hydrogen a) Number of moles of carbon 1 molecule of CH3CHO contains 2 C-atoms. Therefore, 2 mol of CH3CHO contains 2×2 = 4 moles of Carbon. b) Number... 1
- N. Calculate the number of moles of magnesium oxide, MgO in i. 80 g and ii. 10 g of the compound. Molar mass of MgO= (atomic mass of Mg)+(atomic mass of O) =24+16 =40 g/mol 1) 80g of MgO number of mol = Given space mass over Molar space m... 1
- O. What is volume of carbon dioxide, CO2 occupying by i. 5 moles and i. 5 moles of CO_(2 )gas measured at STP. Solution :: molar volume of gas at STP is 22.4 dm³ mol⁻¹ (n)Number of moles of gas = Volumespace o... 1
- P. Calculate the mass of potassium chlorate required to liberate 6.72 dm3 of oxygen at STP beginmatrix 2KClO₃ &→ 2KCl&+3O₂\\ 2moles & & 3 moles endmatrix 2 moles of KClO₃ = 2× 122.5=245g 3 moles of O₂ =3× 22.4=67.2 dm³ hence , 245... 1
- Q. Calculate the number of atoms of hydrogen present in 5.6 g of urea, (NH2 )2 CO No of atoms of H= 2.24× 10²³ , N= 1.124× 10²³ , C= 0.562×10²³, O= 0.562× 10²³ 1
- R. Calculate the mass of sulfur dioxide produced by burning 16 g of sulfur in excess of oxygen in contact process. Answer is 32 grams 1
- Explain The need of the term average atomic mass i. Several naturally occurring elements exist as a mixture of two or more isotopes. ii. Isotopes have different atomic masses. iii. The atom... 1
- Explain Molar mass. The mass of one mole of a substance (element/compound) in grams is called its molar mass. The molar mass of any element in grams is numerica... 1
- Explain Mole concept. Even a small amount of any substance contains very large number of atoms or molecules. Therefore, a quantitative adjective 'mole' is used to... 1
- Explain Formula mass with an example. The formula mass of a molecule (also known as formula weight) is the sum of the atomic weights of the atoms in the empirical formula of the... 1
- Explain : Molar volume of gas. One mole of any gas occupies a volume of 22.4 dm³ at standard temperature (0^o C) and pressure (1 atm) (STP). The volume of 22.4 dm3 at STP... 1
- F. Types of matter (on the basis of chemical composition). On the basis of composition, matter can be classified as compound, element and mixture. Solids, liquids and gases are physical states of mat... 2
- State the law of multiple proportions When two elements A and B form more than one compounds, the masses of element B that combine with a given mass of A are always in the ratio... 1
- State and explain the law of conservation of mass 'mass can neither be created nor destroyed' this law is know as law of conservation of mass . Antoine Lavoisier carefully performed many com... 1
- What is meant by molar volume of a gas ? One mole of any gas occupies a volume of 22.4 dm3 at standard temperature (0^o C) and pressure (1 atm) (STP). The volume of 22.4 dm³ at STP... 1
- What is the SI unit of amount of a substance ? Answer: The SI unit of amount of substance is the mole (symbol: mol). The mole is one of the seven SI base units. One mole is the amount of... 1
- How many particles are present in 1 mole of a substance ? The number of particles present in 1 mole is 6.022 × 10²³ It is Avogadro's number equal to 6.022×10²³ and is expressed as the symbol N_A. 1
- Calculate the molecular mass of the following in u. a. NH3 b. CH3 COOH c. C2 H5 OH A) NH_(3 ) _(molecular mass of )NH_(3 =(1 × atomic space mass space of space N ) ) + (3× atomic mass of H) =(1×14 u)+(3× 1u) =17 u B) CH_(3... 1
- How many grams does an atom of hydrogen weigh ? The weight of 1 atom of hydrogen is calculated as 1.66058 × 10⁻²⁴ grams. Explaination : we know that 1 molecule is made up of 6.023 ×10²³ at... 2
- Point out the difference between 12 g of carbon and 12 u of carbon 12 g of carbon is the molar mass of carbon and 12 u of carbon is the mass of one carbon atom since , 1u= 1 atomic mass unit =1.661 × 10⁻²⁷ k... 1
- A. State and explain Avogadro's law. In 1811, Avogadro proposed that equal volumes of all gases at the same temperature and pressure contain equal number of molecules According... 1
- 1. Choose the most correct option A sample of pure water, whatever the source always contains The answer is highlighted in question like this correct answer Answers ) Q1. Choose the most correct option A) a. 88.9 B) d. Na₂S, NaF C) a.... 1
- Formation of real image using a biconvex lens is shown below If the whole set up is immersed in water without disturbing the object and the The correct option is image disappers Explainnation :: from space 1over f=(μ_rel-1)(1over R₁-1over R₂) Focal length of lens will change henc... 1
- A load of mass M kg is suspended from a steel wire of length 2m and radius 1.0mm in Searle's apparatus The correct answer is option B) 3.00 mm Explaination :: 1