Here is a good Q

[adrakdavra]

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A vertically oriented spring is stretched by 0.50 m when a mass of 1 kg is suspended from it. What is the work done on the spring?

5.0 J
2.5 J
0.5 J
20.0 J

 

[Temperature101]

A vertically oriented spring is stretched by 0.50 m when a mass of 1 kg is suspended from it. What is the work done on the spring?

5.0 J
2.5 J
0.5 J
20.0 J

Free body diagram: Force acting up and Weight acting down ----> F = mg = 10N

Spring constant: F = kx -----> 10 = k (0.5) ----> k = 20 N/m

Work: E = 1/2kx^2 -----> E = 2.5 J....... Am I correct?

 

[adrakdavra]

s

Free body diagram: Force acting up and Weight acting down ----> F = mg = 10N

Spring constant: F = kx -----> 10 = k (0.1) ----> k = 20 N/m

Work: E = 1/2kx^2 -----> E = 2.5 J....... Am I correct?

Yes you are 👍 not that many people got this Q right, that tell you something.....😎

Here is another Q I got it right but I don't fully understand it

In the manufacture of HCl, 10 grams of chlorine gas were used. If the reaction went to completion and the hydrogen gas was in excess, how many grams of HCl were obtained?

2.5
5.1
10.3 *
20.0

 

[Temperature101]

s

Yes you are 👍 not that many people got this Q right, that tell you something.....😎

Here is another Q I got it right but I don't fully understand it

In the manufacture of HCl, 10 grams of chlorine gas were used. If the reaction went to completion and the hydrogen gas was in excess, how many grams of HCl were obtained?

2.5
5.1
10.3 *
20.0

answer: C .... There are 35.5 grams of Cl to 1 gram of H in HCl. If they are using 10 grams of Cl, which is lower than 1/3 of its atomic weight, the reaction also have to use 1/3 of H....10 + 0.3 = 10.3g of HCl

 

[gettheleadout]

s

Yes you are 👍 not that many people got this Q right, that tell you something.....😎

Here is another Q I got it right but I don't fully understand it

In the manufacture of HCl, 10 grams of chlorine gas were used. If the reaction went to completion and the hydrogen gas was in excess, how many grams of HCl were obtained?

2.5
5.1
10.3 *
20.0

Almost all the mass of HCl is from Cl, so with H2 as the limiting reactant we can assume all of this mass will show up in HCl. Adding in the little additional mass from the proton, and we get a mass of HCl very slightly higher than 10g. No math involved.