For question #12, use the following picture: 12. What element is this? How do you know?
2 answers:
Answer: The element shown in the image is Helium (He).
Explanation: We are given a image of an atom having protons, neutrons and electrons.
Number of protons as shown in image = 2
Number of neutrons as shown in image = 2
Number of electron as shown in image = 2
Atomic number = Number of protons = Number of electrons
Atomic number of the element = 2
Atomic Mass = Number of protons + Number of neutrons
Atomic mass = 2 + 2 = 4
The element having Atomic number = 2 and mass number = 4 is Helium.
Element =
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Answer:
The volume of this sample when the temperature is changed to 150 K and the pressure is changed to 160 kPa is 52.5 mL.
Explanation:
Boyle's law says that: "The volume occupied by a certain gaseous mass at constant temperature is inversely proportional to pressure" and is expressed mathematically as:
P * V = k
where k is a constant.
Charles's Law consists of the relationship that exists between the volume and the temperature of a certain quantity of ideal gas, which is maintained at a constant pressure, by means of a constant of proportionality that is applied directly. So Charles's law is a law that mathematically says that when the amount of gas and pressure are kept constant, the quotient that exists between the volume and the temperature will always have the same value:
Gay-Lussac's law states that the pressure of a fixed volume of a gas is directly proportional to its temperature. In other words, if the volume of a certain quantity of ideal gas remains constant, the quotient between pressure and temperature remains constant:
Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:
Considering an initial state 1 and a final state 2, it is satisfied:
In this case:
- P1: 240 kPa
- V1: 70 mL
- T1: 300 K
- P2: 160 kPa
- V2: ?
- T2: 150 K
Replacing:
Solving:
V2= 52.5 mL
<u><em>The volume of this sample when the temperature is changed to 150 K and the pressure is changed to 160 kPa is 52.5 mL.</em></u>