Answer:
The number of neutrons is entirely dependent on the Mass number of the particular atom. The standard mass for potassium is 39.
Potassium is element number 19, so it has 19 protons and 19 electrons in the neutral atom. It has therefore 39-19 = 20 Neutrons.
Explanation:
Answer: B) 46.7% Si and 53.3% O
Explanation:
To calculate the mass percent of element in a given compound, we use the formula:
Mass of quartz = 5.05 g
Mass of silicon = 2.36 g
Mass of oxygen = Mass of quartz - mass of silicon = 5.05g - 2.36 g = 2.69 g
Thus the percentages of silicon and oxygen in quartz are B) 46.7% Si and 53.3% O
H₂ is the limiting reactant.
<u>Explanation:</u>
H₂ reacts with O₂
The reaction would be
2H₂ + O₂ → 2H₂O
According to the balanced equation, 2 moles of H₂ reacts with 1 mole of O₂ to form 2 moles of H₂O.
The ratio of usage of H₂ and O₂ is 2 : 1 respectively
If 3 moles of H₂ and 2 moles of O₂ are present then:
3 moles of H₂ would require 1.5 moles of O₂ ( 2 : 1 of H₂ and O₂ )
Out of 2 moles of O₂, 1.5 moles would be used and 0.5 mole would be in excess.
Therefore, H₂ is the limiting reactant as the number of moles of H₂ are not enough to use all the O₂.
Answer:
T₂ = 19.95°C
Explanation:
From the law of conservation of energy:
where,
mc = mass of copper = 37.2 g
Cc = specific heat of copper = 0.385 J/g.°C
mw = mass of water = 188 g
Cw = specific heat of water = 4.184 J/g.°C
ΔTc = Change in temperature of copper = 99.8°C - T₂
ΔTw = Change in temperature of water = T₂ - 18.5°C
T₂ = Final Temperature at Equilibrium = ?
Therefore,
<u>T₂ = 19.95°C</u>