19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
1.0 g of magnesium is burnt with 0.56 g O2 in a closed vessel. Which reactant is left in excess and how much? (At. wt. Mg = 24, O = 16) (NEET 2014)
When 22.4 litres of H2(g) is mixed with 11.2 litres of Cl2(g), each at STP, the moles of HCl(g) formed is equal to (NEET 2014)
Equal masses of H2, O2 and methane have been taken in a container of volume V at temperature 27°C in identical conditions. The ratio of the volumes of gases H2 : O2 : methane would be (NEET 2014)
6.02 × 1020 molecules of urea are present in 100 mL of its solution. The concentration of solution is (NEET 2013)
A sample of calcium carbonate (CaCO3) has the following percentage composition: Ca = 40%, C = 12%, O = 48%. If the law of constant proportions is true, then the weight of calcium in 4g of a s…
Hydrogen and oxygen combine to form H2O2 and H2O containing 5.93% and 11.2% hydrogen respectively. The data illustrates:
The percentage of copper and oxygen in samples of CuO obtained by different methods were found to be the same. This illustrates the law of
The law of multiple proportion is illustrated by
Carbon and oxygen combine to form two oxides, carbon monoxide and carbon dioxide in which the ratio of the weights of carbon and oxygen is respectively 12:16 an 12:32. These figures illustrate the:
Which of the following reaction is not according to the law of conservation of mass
Who proposed Law of Conservation of Mass?
If 6.3g of NaHCO3 are added 15.0g CH3COOH solution, the residue is found to weigh 18.0 g. What is the mass of CO2 released in the reaction?
One of the statements of Dalton’s atomic theory in given below “Compounds are formed when atoms of different elements combine in a fixed ratio” Which of the following laws is not related to this…
_________is referred to as the closeness of different measurements for the same quantity.
How many significant figures are present in 0.10100 × 103?
Which of the following is the most accurate measurement?
The result of the operation 2.5 × 1.5 should be which of the following on the basis of significant figures?
2.005 has ….A…. significant figures. Here, A refers to
How can we write 232.508 in scientific notation?
A metal M of equivalent mass E forms an oxide of molecular formula MxOy. The atomic mass of the metals is given by the correct equation (BCECE 2008)
Which of the following represents the largest unit?
Statement I: The temperatures in degree Celsius and degree Fahrenheit are related to each other by the following relationship. º F º C Statement II The temperature on degree Celsius and Kelvi…
Which of the following statements(s) is false about the arrangement of particles, in different states of matter?
An antifreeze mixture contains 40% ethylene glycol (C2H6O2) by weight in the aqueous solution. If the density of this solution is 1.05 g/mL, what is the molar concentration?
The density (in g mL–1) of a 3.60 M sulphuric acid solution that is 29% H2SO4 (molar mass = 98 g mol-1) by mass will be MOLE & EQUIVALENT CONCEPT