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

Athermometer is removed from a room where the temperature is 70° f and is taken outside, where the air temperature is 10° f. after one-half minute the thermometer reads 60° f. what is the reading of the thermometer at t = 1 min? (round your answer to two decimal places.) ° f how long will it take for the thermometer to reach 30° f? (round your answer to two decimal places.)

Astudent is performing an experiment comparing sound and light waves. the student gathers the following data. what conclusion does the student most likely make based on this data? light waves always travel the same speed; however, the speed of sound is determined by the medium that it travels through. all sound waves always have the same energy, so the temperature of the medium does not affect wave speed. light needs to vibrate particles, so it travels fastest in tightly packed solids, while sound does not need a medium, so it travels fastest in a gas. tightly packed particles in solids slow down the light waves; however, sound waves make particles bounce into each other, so they travel faster in solids.

The dot diagram represents the motion of the motorcycle as it moves from left to right