EASY
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One part of an element A combines with two parts of another element B. 6 parts of element C combines with 4 parts of B. If A and C combine together, the ratio of their weights will be governed by.

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Important Questions on Some Basic Concepts of Chemistry

MEDIUM

The ammonia is prepared by treating ammonium sulphate with calcium hydroxide is completely used by NiCl2·6H2O to form a stable coordination compound. Assume that, both the reactions are 100% completed. If 1584 g of ammonium sulphate and 952 g of NiCl2·6H2O are used in the preparation, the combined weight (in grams) of gypsum and the nickel ammonia coordination compound produced is ____.

Atomic weights in g mol-1:

H=1; N=14 O=16; S=32 Cl=35.5; Ca=40 Ni=59

HARD
A mixture of 100 m mol of Ca(OH)2 and 2 g of sodium sulphate was dissolved in water and the volume was made up to 100 mL. What is the mass of calcium sulphate formed and the concentration of OH- in resulting solution, respectively? (Molar mass of CaOH2, Na2SO4 and CaSO4 are 74, 143  and 136 gmol-1, respectively; Ksp of CaOH2 is5.5×10-6)
HARD

Galena (an ore) is partially oxidized by passing air through it at high temperature. After some time, the passage of air is stopped, but the heating is continued in a closed furnace such that the contents undergo self-reduction. The weight (in kg) of Pb produced per kg of O2 consumed is ____. (Atomic weights in g mol-1: O=16, S=32, Pb=207)

Give the answer to the nearest integer value.

MEDIUM

A gaseous hydrocarbon on combustion gives 0.72 g of water and 3.08 g CO2. What is the empirical formula of the hydrocarbon?

EASY
Among the following pairs of compounds, the one that does not illustrate the law of multiple proportions, is
EASY
What is the mass of the precipitate formed when 50 mL of 16.9% solution of AgNO3 is mixed with 50 mL of 5.8% NaCl solution?

(Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5)
EASY
For the following reaction, the mass of water produced from 445 g  of C57H110O6 is: 2 C57H110O6s+163O2g114 CO2g+110H2Ol
MEDIUM
The amount of metallic Zn  (Atomic weight = 65.4) required to react with aqueous sodium hydroxide to produce 1 g of H2 is
MEDIUM
By heating 200 g of metal carbonate, 112 g of metal oxide on a gaseous compound are produced. Vapour density of the gaseous compound is 22. How many moles of gaseous compound is produced in the reaction?
MEDIUM

In the following reaction:

A+2B+3CAB2C3
6.0 g of A, 6.0×1023  atoms of B and 0.036 mol of C reacted and formed 4.8 g of compound AB2C3. If the atomic mass of A  and C are 60 and 80 amu, respectively. What is the atomic mass of B in amu? (Avogadro number=6×1023)

MEDIUM
56.0 L of nitrogen gas is mixed with excess of hydrogen gas and it is found that 20 L of ammonia gas is produced, The volume of unused nitrogen gas is found to be_____ L.
EASY
1 gram of a carbonate M2CO3 on treatment with excess HCl produces 0.01186 moles of CO2 . The molar mass of M2CO3 in  gmol-1 is:
MEDIUM
20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample?

(Atomic weight: Mg = 24)
EASY
What is the quantity of hydrogen gas liberated when 46 g sodium reacts with excess ethanol? (Given Atomic mass of Na = 23 g)
MEDIUM
When 262 g of xenon (atomic mass = 131) reacted completely with 152 g of fluoride (atomic mass = 19), a mixture of XeF2 and XeF6 was produced. The molar ratio of XeF2 :XeF6 is
MEDIUM
When 22.4 L of C4H8 at STP is burnt completely, 89.6 L of CO2 gas at STP and 72 g of water are produced.
The volume of the oxygen gas at STP consumed in the reaction is closest to
MEDIUM
The molecular formula of a commercial resin used for exchanging ions in water softening is C8H7SO3Na molecular weight=206. What would be the maximum uptake of Ca2+ ions by the resin if expressed in mol per gm?
MEDIUM
Which of the following have same number of significant figures?
(A) 0.00253
(B) 1.0003
(C) 15.0
(D)163
Choose the correct answer from the options given below
EASY
Which of the following is an example of Law of multiple proportion?