Prin electroliza apei s-au obținut 15 L de hidrogen la temperatura de 27 °C şi presiunea de 1,66•10 Pa. Să se determine:
a) masa hidrogenului obținut;
b) echivalentul electrochimic al hidrogenului;
c) energia electrică consumată, dacă electroliza are loc la o tensiune de 5 V.
Pierderile de energie se neglijează.
Se vor lua: constanta universală a gazelor R = 8,3 J/(mol · K); constanta
(numărul) lui Faraday F = 96 500 C/mol.

Blank liquids and gases exert a buoyant force on objects placed in them

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 2 options: the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the cold balloon expands and rises. the warm balloon shrinks and sinks. the warm balloon expands and rises. the cold balloon shrinks and sinks.

Hydrogen atoms are excited by a laser to the =4n=4 state and then allowed to emit. what is the maximum number of distinct emission spectral lines (lines of different wavelengths) that can be observed from this system? 8 6 2 7 4 5 1 3 calculate the wavelength of the 4⟶14⟶1 transition. =λ=