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How did the name 'hydrogen' originate?

Write the co-ordinates of origin .

The digits of a two-digit number differ by 3 If the digits are interchanged and the resulting number is added to the original number we get 143 What can be the original number

One of the two digits of a two digit number is three times the other digit. If you interchange the digits of this two-digit number and add the resulting number to the original number, you get 88. What is the original number?

An ideal gas intially has pressure P volume V and temperature T . Its is isothermally expanded to four times of its original volume, then it is compressed at constant pressure to attain its original volume V . Finally, the gas is heated at constant volume to get the original temperature T . (a) Draw V-T curve (b) Calculate the total work done by the gas in the process.(given ln2 = 0.693)

For a first order reactions, the half -life is 10 mins. How much time in minutes will it take to reduce the concentration of reactant to 25% of its original concentration ?

Suppose 4 letters are taken out of 4 different envelopes. In how many ways, can they be reinserted in the envelopes so that no letter goes in to its original envelope?

How many anomalous pairs were present in original Mendeleev periodic table ?