53 if your talking about electrons. 74 if your talking about neutrons. energy levels=5
Hope this helps☺️
The question is incomplete, the complete question is;
Which statement describes a difference between electromagnetic and mechanical waves?
A. Mechanical waves cannot be longitudinal, but electromagnetic waves can.
B. Electromagnetic waves cannot move particles, but mechanical waves can.
C. Electromagnetic waves do not require a medium, but mechanical waves do.
D. Mechanical waves do not transfer energy, but electromagnetic waves do.
Answer:
Electromagnetic waves do not require a medium, but mechanical waves do.
Explanation:
A wave is defined as a disturbance along a medium which transfers energy. Waves may be classified as mechanical waves or electromagnetic waves based on their medium of propagation.
A mechanical wave requires a material medium for propagation. An example of a mechanical wave is sound waves. Sound waves are propagated in air.
Electromagnetic waves do not require a material medium for propagation. They can travel through space. An example of electromagnetic waves is light waves.
I believe the oxygen atom has 8 protons and 8 neutrons.
<span>
1. Remember (sum of products) - (sum of reactants)
So ΔHrxn = 2 ΔHf [H2(g)] + ΔHf [Ca(OH)2(s)] - 2 ΔHf [H2O(l)] - ΔHf [Ca(s)]
= 2*0 + -986.09 kJ/mol - 2*(-285.8 kJ/mol) - 0
Do the math and you'll have the answer. BTW the ΔHf [H2(g)] and ΔHf
[Ca(s)] were 0 because these are elements in their standard states.
</span>HOPE THIS HELPS ;)
Answer:
The mass of cryolite will be produced = 71247 g or, 71.247 kg
Explanation:
The balanced chemical equation for the synthesis of cryolite
Al₂O₃(s) + 6 NaOH(l) + 12 HF(g) → 2 Na₃AlF₆ + 9 H₂O(g)
