Students in a science class observed that when a strip of Magnesium (Mg) metal was placed in a test tube containing Hydrobromic acid (HBr), the Magnesium began to bubble as hydrogen gas and Magnesium Bromide are formed. Which of the following choices show both the correctly balanced equation and identify the type of reaction? A.
Mg+2HBr →H2+MgBr2 (synthesis)

B.
2Mg+HBr →H2+2MgBr2 (decomposition)

C.
Mg+2HBr →H2+MgBr2 (single replacement)

D.
Mg+2HBr →2H2+MgBr2 (double replacement)

Pls help, I'll mark brainiest, I really need a good grade, so pls answer correctly

Imagine you are riding on a yacht in the ocean and traveling at 20 mph. you then hit a golf ball at 100 mph from the deck of the yacht. you see the ball move away from you at 100mph, while a person standing on a near by beach would observe your golf ball traveling at 120 mph (20 mph + 100 mph). now imagine you are aboard the hermes spacecraft traveling at 0.1c (1/10 the speed of light) past mars and shine a laser from the front of the ship. you would see the light traveling at c (the speed of light) away from your ship. according to einstein’s special relativity, how fast will a person on mars observe the light to be traveling? a) 0.1c (1/10 the speed of light) b) c (the speed of light) c)1.1c (c+0.1c)

An electron is traveling with initial kinetic energy k in a uniform electric field. the electron comes to rest momentarily after traveling a distance d. (a) what is the magnitude of the electric field

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