Answer:
a) Xbenzene = 0.283
b) Xtoluene = 0.717
Explanation:
At T = 20°C:
⇒ vapor pressure of benzene (P*b) = 75 torr
⇒ vapor pressure toluene (P*t) = 22 torr
Raoult's law:
∴ Pi: partial pressure of i
∴ Xi: mole fraction
∴ P*i: vapor pressure at T
a) solution: benzene (b) + toluene (t)
∴ Psln = 37 torr; at T=20°C
⇒ Psln = Pb + Pt
∴ Pb = (Xb)*(P*b)
∴ Pt = (Xt)*(P*t)
∴ Xb + Xt = 1
⇒ Psln = 37 torr = (Xb)(75 torr) + (1 - Xb)(22 torr)
⇒ 37 torr - 22 torr = (75 torr)Xb - (22 torr)Xb
⇒ 15 torr = 53 torrXb
⇒ Xb = 15 torr / 53 torr
⇒ Xb = 0.283
b) Xb + Xt = 1
⇒ Xt = 1 - Xb
⇒ Xt = 1 - 0.283
⇒ Xt = 0.717
Answer:
The main advantage would be that with the pouring temperature being much higher, there is very little chance that the metal will solidify in the mould while busy pouring. This will allow for moulds that are quite intricate to still be fully filled. The drawbacks, though, include an increased chance defects forming which relates to shrinkage (cold shots, shrinkage pores, etc). Another drawback includes entrained air being present, due to the viscosity of the metal being low because of the high pouring temperature.
Answer:
The direction will be changed
.
Explanation:
According to the principles of motion, if an object is moving with solitary velocity and if an external force is applied to it, then that force changes the position, speed, and direction of that object.
In the given question, an external force is being applied to the toy which will change the direction of that toy.
“Models are developed when a scientist’s creativity and insight are combined with data and observations about many similar scenarios”. Models are used for a lot of things in science. As we know everything has advantages and disadvantages, and the same applies to models. Models help us illustrate the concept and formulate hypothesis. When models are used, the scientists are able to notice patterns and develop and revise representation that become a useful model, which makes their scientific knowledge stronger and helps them understand more about the nature of science. Models are a simplified representation. One of the biggest advantages of the model is, that it allows you to have a look at things which are too small such as atoms or too big such as the solar system.
Although, having many benefits, models have quite a number of disadvantages. Models sometimes oversimplify the process therefore leading to a misunderstanding. As models are supposed to be a simplified representation, they will not be complex, which means they will lack detail. For Example “our particle model explains many things about matter, it is not comprehensive — for example, it cannot predict why certain materials have different electrical properties. We could add further refinements that are outside the scope of this course to enable it to do so, but it would make our model so complicated that it would no longer be useful to us”
I think it is because it is directly about the north or south pole (I forget) so while all the other stars seem to rotate around because the Earth is rotating but the North Star is directly in the center. Don't take my word though.
