Assuming that the following reaction is performed at stp, how many ml of oxygen are needed to react with 50ml of h2 gas in synthesis of water

equation given 2h2+o2 = 2h2o

The balanced chemical reaction is written as:

2H2+O2 = 2H2O

We are given the amount of H2 gas to be used in the reaction. This will be used as the starting point for the calculations. We calculate as follows:

.050 L H2 ( 1 mol H2 / 22.4 L H2 ) ( 1 mol O2 / 2 mol H2 ) ( 22.4 L / 1 mol ) = 0.025 L O2 or 25 mL O2

Google it that might work

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

explanation

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.