Answer:
The mass of PbSO4 formed 15.163 gram
Explanation:
mole of Pb(NO₃)₂ = 1.25 x 0.05 = 0.0625
mole of Na₂SO₄ = 2 x 0.025 = 0.05
Pb(NO₃)₂ + Na₂SO₄ → PbSO₄ + 2 NaNO₃
( Mole/Stoichiometry ) 
= 0.0625 = 0.05
From (Mole/ Stoichiometry ) we can conclude that Na₂SO₄ is limiting reagent.
Mass of PbSO₄ precipitate = 0.05 x Molecular mass of PbSO₄
= 0.05 x 303.26 g
= 15.163 g
Answer:Phase changes require either the addition of heat energy (melting, evaporation, and sublimation) or subtraction of heat energy (condensation and freezing). ... Changing the amount of heat energy usually causes a temperature change.
Explanation:
To increase the energy of the emitted electrons, the frequency of the incident light on the metal must be increased.
<h3>What is energy of emitted electron?</h3>
The maximum energy of an emitted electron is equal to the energy of a photon for frequency f (E = hf ), minus the energy required to eject an electron from the metal's surface, also known as work function.
Ee = E - W
<h3>Energy of the emitted electron</h3>
The energy of emitted electrons based on the research of Albert Einstein is given as;
E = hf
where;
- h is planck's constant
- f is frequency of incident light on the metal
Thus, to increase the energy of the emitted electrons, the frequency of the incident light on the metal must be increased.
Learn more about energy of electron here: brainly.com/question/11316046
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