How many liters of hydrogen are obtained from the reaction of 4.00 g sodium with excess water, at STP?

V = 1.95 L.

Explanation:

Hell there!

In this case, according to the following reaction between sodium metal and water:

We can realize that the moles of hydrogen can be calculated by using the initial mass of sodium, its atomic mass (23.0 g/mol) and the 2:1 mole ratio of sodium to hydrogen to obtain:

Finally, we calculate the volume of hydrogen by using the ideal gas equation whereas the pressure is 1 atm and the temperature 273.15 K according to the STP conditions:

Regards!

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.