A sample of Vitamin C is known to contain 2.58 ×1024 oxygen atoms. How many moles of oxygen atoms are present in the sample?
Answer: 4.28 mol One mole of a substance is equal to the substance’s 6,022 x 1023 units. The 6.022 x... View Article
Latest Posts
The mass of one steel screw is 4.11g. Find the mass of one mole of these steel screws. Compare this value with the mass of the Earth (5.98 × 1024kg). Which one of the two is heavier and by how many times?
Answer: Mass of one steel screw = 4.11g Mass of Earth = 5.98 × 1024 kg = 5.98 × 1027... View Article
Cinnabar (HgS) is a prominent ore of mercury. How many grams of mercury are present in 225 g of pure HgS? Molar mass of Hg and S are 200.6 g mol-1 and 32 g mol-1 respectively.
Answer: Molar mass of HgS = The molar mass of Hg + the molar mass of S The molar mass... View Article
The difference in the mass of 100 moles each of sodium atoms and sodium ions is 5.48002 g. Compute the mass of an electron.
Answer: 9.1×10-31 kg Sodium atom and ion differ by one electron. For 100 moles each of sodium atoms and ions... View Article
Calcium chloride when dissolved in water dissociates into its ions according to the following equation. CaCl2 (aq) → Ca2 + (aq) + 2Cl– (aq) Calculate the number of ions obtained from CaCl2 when 222 g of it is dissolved in water.
Answer: 3.6132 × 1024 ions 1 mole of calcium chloride (CaCl2) = 111g ∴ 222g of CaCl2 is equivalent to... View Article
Find the ratio by mass of the combining elements in the following compounds. (You may use Appendix-III) (a) C2 H5 OH (b) NH3 (c) Ca(OH)2
Answer: The total sum of the masses of the atoms or elements present in the molecule is termed as molecular... View Article
Find the ratio by mass of the combining elements in the following compounds. (You may use Appendix-III) (a) CaCO3 (d) C2 H5 OH (b) MgCl2 (e) NH3 (c) H2 SO4 (f) Ca(OH)2
Answer: The total sum of the masses of the atoms or elements present in the molecule is termed as molecular... View Article
Verify by calculating that 240 g of calcium and 240 g magnesium elements have a mole ratio of 3:5.
Answer: Relative molar mass is defined as the smallest mass unit of a compound with one twelfth of the mass... View Article
Verify by calculating that (a) 5 moles of CO2 and 5 moles of H2 O do not have the same mass.
Answer: Relative molar mass is defined as the smallest mass unit of a compound with one twelfth of the mass... View Article
Calculate the number of moles of magnesium present in a magnesium ribbon weighing 12 g. Molar atomic mass of magnesium is 24 g mol-1.
Answer: A mole is defined as the mass of the substance which consists of the equal quantity of basic units.... View Article
You are provided with a fine white coloured powder which is either sugar or salt. How would you identify it without tasting? To examine if the fine white coloured powder is sugar pr salt we can conduct two experiments.
Answer: Heating the given fine white coloured powder Sugar melts to liquid form when heated because sucrose has a decomposition... View Article
Classify each of the following on the basis of their atomicity. (a) F2 (b) NO2 (c) N2O (d) C2H6 (e) P4 (f) H2O2 (g) P4O10 (H) O3 (i) HCl (j) CH4 (k) He (l) Ag
Answer: Atomicity can be defined as the total number of atoms that composes a molecule. Simply put, it is the... View Article
Does the solubility of a substance change with temperature? Explain with the help of an example.
Answer: Solubility is the ability of a solute to get dissolved in 100g solvent. Solubility of a given solute to... View Article
What is the fraction of the mass of water due to neutrons?
Answer: 0.4444 Mass of one mole of a substance is equal to its relative atomic or molecular mass in grams.... View Article
State the number of atoms present in each of the following chemical species (a) CO3-2 (b) PO4-3 (c) P2O5 (d) CO
Answer: (a) CO3-2 The number of atoms in CO32- = Atom of carbon + Atom of oxygen Atom of carbon... View Article
Give the chemical formulae for the following compounds and compute the ratio by mass of the combining elements in each one of them. (You may use appendix-III). (a) Ammonia (b) Carbon monoxide (c) Hydrogen chloride (d) Aluminium fluoride (e) Magnesium sulphide
Answer: S. No. Compounds Chemical formula Ratio by mass of the combining elements (a) Ammonia NH3 N:H = 14:3 (b)... View Article
Which of the following symbols of elements are incorrect? Give their correct symbols (a) Cobalt CO (b) Carbon c (c) Aluminium AL (d) Helium He (e) Sodium So
Answer: The Periodic table generally displays only the symbol of the element and not its entire name. Most of the... View Article
Give the formulae of the compounds formed from the following sets of elements (a) Calcium and fluorine (b) Hydrogen and sulphur (c) Nitrogen and hydrogen (d) Carbon and chlorine (e) Sodium and oxygen (f) Carbon and oxygen
Answer: (a) Calcium and fluoride Calcium Fluoride (CaF2) (b) Hydrogen and sulphur Hydrogen Sulphide (H2S) (c) Nitrogen and hydrogen Ammonia... View Article
Write the cations and anions present (if any) in the following compounds (a) CH3COONa b) NaCl (c) H2 (d) NH4NO3
Answer: An anion may be defined as an atom or molecule that is negatively charged. A cation may be defined... View Article
Write the molecular formulae of all the compounds that can be formed by the combination of following ions Cu2+, Na+, Fe3+, Cl– SO4-2, PO4-3
Answer: The molecular formula is the expression of the number of atoms of each element in one molecule of a... View Article
