Physics and Chem Question (1 Viewer)

[Shoom]

How much energy would be used by a 100W globe and 50W fan operating non stop for 2 days?

Show working please.

Calculate the mass of silver formed by the thermal decomposition of Silver Oxide. 5.00g of Silver Oxide was decomposed.


THANKS
SHOW ALL WORKING PLEASE.

 

[ratcher0071]

How much energy would be used by a 100W globe and 50W fan operating non stop for 2 days?

Show working please.

Calculate the mass of silver formed by the thermal decomposition of Silver Oxide. 5.00g of Silver Oxide was decomposed.


THANKS
SHOW ALL WORKING PLEASE.

Energy(J)=Power(W) x Time(s)
E=(100 + 50) x (2days x 24hours x 60mins x 60seconds)
E=(150) x (172800)
E=25920000 Joules
E=25920 kJ
E=25.92 MJ

For the 2nd question i don't know.

 

[Shoom]

I thought you divide by 1000 and time by 48. Now its in kw.h. The Jacaranda textbook says calculating energy in kw.h and thats how they do it. But your answer is right.

 

[kaz1]

How much energy would be used by a 100W globe and 50W fan operating non stop for 2 days?

Show working please.

Calculate the mass of silver formed by the thermal decomposition of Silver Oxide. 5.00g of Silver Oxide was decomposed.


THANKS
SHOW ALL WORKING PLEASE.

For the second question.

Ag₂O

Molar Mass of Ag₂O=(107.9 x 2) + 16
=231.8
Percentage of Silver in the Compound is 215.8/231.8 x 100 = 93%
93% of 5g is 4.655g
Therefore there is 4.655g of Silver.

I just had a jab at it. I never done that type of question before.

 

[Shoom]

A 12 volt battery placed in a series circuit with 2ohm and 4ohm resistors. The current flowing and the power dissapated in the 4ohm resistor would be?

Ook I= 2A, P=v^2/r or I^2 R I can get 16 both ways.

 

[VenomP]

How much energy would be used by a 100W globe and 50W fan operating non stop for 2 days?

Show working please.

Calculate the mass of silver formed by the thermal decomposition of Silver Oxide. 5.00g of Silver Oxide was decomposed.


THANKS
SHOW ALL WORKING PLEASE.

Physics

Energy in kilowatt-hours (globe) = power in kilowatts x time in hours
0.100 x 48 = 4.8

Energy in kilowatt hours (fan) = power in kilowatts x time in hours
0.050 x 48 = 2.4

Total = 4.8 + 2.4
= 7.2 Kilowatts

I think that's right. Might get someone else to check, though.

As for Chem, I have no idea.

 

[ratcher0071]

For the second question.

Ag₂O

Molar Mass of Ag₂O=(107.9 x 2) + 16
=231.8
Percentage of Silver in the Compound is 215.8/231.8 x 100 = 93%
93% of 5g is 465.5g
Therefore there is 465.5g of Silver.

I just had a jab at it. I never done that type of question before.

93% of 5g is 4.65g

 

[ratcher0071]

Physics

Energy in kilowatt-hours (globe) = power in kilowatts x time in hours
0.100 x 48 = 4.8

Energy in kilowatt hours (fan) = power in kilowatts x time in hours
0.050 x 48 = 2.4

Total = 4.8 + 2.4
= 7.2 Kilowatts

I think that's right. Might get someone else to check, though.

As for Chem, I have no idea.

7.2 Kilowatt hours is correct.

 

[ratcher0071]

A 12 volt battery placed in a series circuit with 2ohm and 4ohm resistors. The current flowing and the power dissapated in the 4ohm resistor would be?

Ook I= 2A, P=v^2/r or I^2 R I can get 16 both ways.

P=I^2 x R
P=2^2 x 4
P=4 x 4
P=16 Watts

to calculate voltage in the 4 ohm resistor
V=IR
V=2 x 4
V= 8 volts

Then use this 8 volts in P=V^2/R
P=8^2/4
P=64/4
P=16 Watts

therefore by using both equations you get 16 watts.

 

[Shoom]

Thanks, thats what I got, the book obviously did a mistake,

 

[kaz1]

93% of 5g is 4.65g

Lol, made a typo.