For which of the following activities might you want to hire a chemist?
Answer: D. testing a rock sample for gold content
Which of the following procedures involves a physical change in one of the substances?
Answer: C. separating a salt solution by evaporating the water
Answer:
C. An electron has a high probability of being in certain regions.
Explanation:
In the electron cloud model, there are no electron-orbits around the nucleus but a cloud. This cloud has various densities with respect to distance from the nucleus. The most dense region of the cloud (which is the region close to the nucleus) is where electrons has the highest probability of existence.
The model explains that an electron a greater chance of being in the region closer to the nucleus. Thus, an electron has a high probability of being in certain region of the cloud about the central nucleus. And an electrostatic force exists between the nucleus and the electrons.
<span>0.453 moles O2 is the solution</span>
Answer: 0.0508mL
Explanation: Using the basic formula that states: C acid * V acid = C base * V base. we have:0.568 * 17.88 = 20 * C base.
therefore concentration of the base is 1.0156/20 = 0.0508 mL
- From the general law of gases: PV = nRT,
where P is the pressure (atm),
V is the volume (L),
n is the number of moles,
R is the general gas constant (8.314 L.atm/mol.K),
T is the temperature in Kelvin
- at constant volume of the gas: P1T2 = P2T1
P1 = 3.20 atm, T1 = 300 K, T2 = 290 K, P2 = ??
(3.20 atm)(290 K) = P2(300 K)
P2 = (3.20 atm)(290 K)/ (300 K) = 3.093 atm
