Answer:
Apparent magnitude
Explanation:
By definition, Apparent magnitude which is usually denoted by "m" is the measure of the brightness of a star or even other astronomical objects that are observed from Earth. Meanwhile the absolute magnitude is defined as the intrinsic luminosity emitted by a star or other astronomical objects.
Thus, apparent magnitude is correct.
Answer:
28.3 °C
Explanation:
We assume that the specific heat of the solution is equal to the specific heat of water (4.184 Jg⁻¹ °C⁻¹).
First, we find the heat released by the dissolution of CaCl₂. The grams will be converted to moles using the molar mass (110.986 g/mol), then multiplied by the molar heat of solution:
(3.00 g)(mol/110.986 g)(-82.8 kJ/mol) = -2.23812 kJ
The negative sign indicates that heat is released. Extra significant figures are included to avoid round-off errors.
The amount of heat released by the CaCl₂ dissolution is equal to the heat absorbed by the water. The equation is rearranged to solve for Δt, the temperature change of the water.
Q = mcΔt ⇒ Δt = Q/(mc)
Δt = (2.23812 kJ)(1000 J/kJ) / (100 mL)(1 g/mL)(4.184 Jg⁻¹ °C⁻¹) = 5.3 °C
We can then calculated the final temperature t₂ of the solution:
Δt = t₂ - t₁
t₂ = Δt + t₁ = 5.3 °C + 23.0 °C = 28.3 °C
Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is a weak acid with the chemical formula H3PO4.
Answer:
1.5 hours or 90 minutes
Explanation:
Velocity = d/t
V = 64 mi / hour or 96 mi / 9 min OR 16 mi / 15 min
D = 96 miles
Velocity * Time = Distance
Time = Distance / Velocity
T = 96 mi / 64 mi / hour
96 / 64 = 1.5 mi per hour
T = 1.5 hours or 90 minutes