For an aqueous solution of MgBr2, a freezing point depression occurs due to the rules of colligative properties. Since MgBr2 is an ionic compound, it acts a strong electrolyte; thus, dissociating completely in an aqueous solution. For the equation:
ΔTf<span> = (K</span>f)(<span>m)(i)
</span>where:
ΔTf = change in freezing point = (Ti - Tf)
Ti = freezing point of pure water = 0 celsius
Tf = freezing point of water with solute = ?
Kf = freezing point depression constant = 1.86 celsius-kg/mole (for water)
m = molality of solution (mol solute/kg solvent) = ?
i = ions in solution = 3
Computing for molality:
Molar mass of MgBr2 = 184.113 g/mol
m = 10.5g MgBr2 / 184.113/ 0.2 kg water = 0.285 mol/kg
For the problem,
ΔTf = (Kf)(m)(i) = 1.86(0.285)(3) = 1.59 = Ti - Tf = 0 - Tf
Tf = -1.59 celsius
Answer:
Modern whales evolved by natural selection over long time periods through descent from common ancestors
Explanation:
According to the evolutionary theory proposed by Darwin, natural selection is a biological process by which organisms adapt and change in response to their environment. In this case, ancient whales that were better suited to environmental conditions survived and produced more offspring than non-adapted individuals. In consequence, predominant adaptive traits observed in modern whales were favored by natural selection in the past, while unsuccessful phenotypes progressively disappeared.
Answer:
80 m/hr
Explanation:
Changes from 20 to 100 meters in ONE Hour
changes 80 meters in one hour = 80 m/hr
1. The answer is; C
The geosphere is made up of the physical rocks (composed of metals and minerals) and magma in the different layers. These densities of these rocks surpass those of other spheres such as the atmosphere and hydrosphere.
2. The answer is; B
Destructive forces break down land. Weathering and erosion are categorized as slow destructive forces because they take many years for their effect to be perceptible to the human's scale. Quick destructive forces are forces such as earthquakes and tsunamis.
3. The answer is; B
The atmosphere on earth is mainly composed of molecular nitrogen at 78%. Oxygen takes up 21% and other gases found in the atmosphere are hydrogen, carbon dioxide,ozone, dust, and water vapor at 1%.
4. The answers that apply are ; A & B
The formula for gravity force is given by the equation.; F(gravity) = (G*m1*m2)/d^2 where G is the gravitational constant, m1 and m2 are the masses of the two objects, and d is the distance between them.
5. The answer is; C
The force of inertia is due to their celestial mass. The larger the mass the higher the inertia. Inertia is the tendency of a moving object to maintain a straight path without an external force applied to it. This, therefore, prevents the moon from being pulled into collision with the earth. Gravity, on the other hand, prevents the moon from flying out of its orbit and away into space.
I believe doctors use (3) Co-60 to treat ILWs. Uranium and Carbon are not used, and a different isotope of lead is used to be attached to monoclonal antibodies.
