Answer:
Indeed, the two samples should contain about the same number of gas particles. However, the molar mass of is larger than that of (by a factor of about .) Therefore, the mass of the sample is significantly larger than that of the sample.
Explanation:
The and the sample here are under the same pressure and temperature, and have the same volume. Indeed, if both gases are ideal, then by Avogadro's Law, the two samples would contain the same number of gas particles ( and molecules, respectively.) That is:
.
Note that the mass of a gas is different from the number of gas particles in it. In particular, if all particles in this gas have a molar mass of , then:
.
In other words,
- .
- .
The ratio between the mass of the and that of the sample would be:
.
Since by Avogadro's Law:
.
Look up relative atomic mass data on a modern periodic table:
Therefore:
- .
- .
Verify whether :
- Left-hand side: .
- Right-hand side: .
Note that the mass of the sample comes with only two significant figures. The two sides of this equations would indeed be equal if both values are rounded to two significant figures.
Answer:
The mass percent of aluminum sulfate in the sample is 16.18%.
Explanation:
Mass of the sample = 1.45 g
Mass of the precipitate = 0.107 g
Moles of aluminum hydroxide =
According to reaction, 2 moles of aluminum hydroxide is obtained from 1 mole of aluminum sulfate .
Then 0.001372 moles of aluminum hydroxide will be obtained from:
Mass of 0.000686 moles of aluminum sulfate :
= 0.000686 mol × 342 g/mol = 0.2346 g
The mass percent of aluminum sulfate in the sample:
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 =
Answer:
d. cells are made of atoms and molecules. :)
Explanation:
hope i helped