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Answer:
a. The student performed the splint test incorrectly. He should of observed a popping sound when the splint was placed in the test tube.
Explanation:
It is given that a student performed an experiment where he dropped a nickel metal in to HCl solution. He observed the reaction and performed a splint test in the test tube that is filled with a gas which is formed while Nickle is dropped into the solution of HCl.
But the experiment that the student performed was incorrect. He must have observed the popping sound when the splint was placed in the test tube.
When the splint was added to the gas splint flared up. The hydrogen gas pops out when exposed to the flame.

Thus the correct option is (a).
Answer: 0.5 kg
Explanation:
Force of launched skyrocket = 10 N
Acceleration of skyrocket = 20 m/s squared (i.e 20m/s^2)
Mass of the skyrocket = ?
Recall that Force is the product of the mass of an object by the acceleration by which it moves.
i.e Force = Mass x Acceleration
10N = Mass x 20m/s^2
Mass = (10N/20m/s^2)
Mass = 0.5 kg
Thus, the mass of this skyrocket is 0.5 kilograms
Answer:
The specific shape that an electron moves in inside a sub-level <em><u>shell</u></em><em><u>.</u></em>
Yes we would be able to live in cold climates.