Answer: The correct option is heterogeneous mixture whose components are attracted differently to a magnet.
Explanation: There are two types of mixtures:
1) Homogeneous mixtures: In these mixtures, the particles are uniformly distributed throughout the mixture. These particles cannot be separated.
2) Heterogeneous Mixtures: These are the mixtures where the particles are visible separated and are not-uniformly distributed. These particles can be separated easily.
If magnet is used to separate the components of a mixture, the heterogeneous mixtures will only get separated.
To separate the components by a magnet, the components of a mixture should attract the magnet differently. One component should attract the magnet and another should not. Hence, they can be easily separated.
<u>Answer:</u>
<u>For Part A:</u> The partial pressure of Helium is 218 mmHg.
<u>For Part B:</u> The mass of helium gas is 0.504 g.
<u>Explanation:</u>
We are given:
To calculate the partial pressure of helium, we use the formula:
Putting values in above equation, we get:
Hence, the partial pressure of Helium is 218 mmHg.
To calculate the mass of helium gas, we use the equation given by ideal gas:
PV = nRT
or,
where,
P = Pressure of helium gas = 218 mmHg
V = Volume of the helium gas = 10.2 L
m = Mass of helium gas = ? g
M = Molar mass of helium gas = 4 g/mol
R = Gas constant = 
T = Temperature of helium gas = 283 K
Putting values in above equation, we get:
Hence, the mass of helium gas is 0.504 g.
The word elliptical refers to an Oval.
Answer:
- <em>He realized that some elements had not been discovered.</em>
Explanation:
Some scientists that tried to arrange the list of elements known before Mendeleev include Antoine Lavoisier, Johann Döbereiner, Alexandre Béguyer de Chancourtois, John Newlands, and Julius Lothar Meyer.
<em>Dimitri Mendeleev</em> was so succesful that he is recognized as the most important in such work.
Mendeleev by writing the properties of the elements on cards elaborated by him, and "playing" trying to order them, realized that, some properties regularly (periodically) repeated.
The elements were sorted in increasing atomic weight (which is not the actual order in the periodic table), but when an element did not meet the pattern discovered, he moved it to a position were its properties fitted.
The amazing creativity of Mendeleev led him to leave blanks for what he thought were places that should be occupied by elements yet undiscovered. More amazing is that he was able to predict the properties of some of those elements.
When years after some of the elements were discovered, the genius of Mendeleev was proven because the "new" elements had the properties predicted by him.
