Please I need help its timed- Students in a science class observed that when a strip of magnesium (Mg) metal was placed in a test tube containing hydrochloric acid (HCl), the magnesium began to bubble as hydrogen gas and magnesium chloride are formed. Which of the following choices show both the correctly balanced equation and identify the type of reaction?

A.

Mg + 2HCl →2H2 + MgCl2 (single replacement)

B.

Mg + 2HCl →H2 + MgCl2 (single replacement)

C.

Mg + 2HCl →H2 + MgCl2 (synthesis)

D.

2Mg + HCl →H2 + 2MgCl2 (synthesis)

c

Explanation:

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000