Answer:
2.83 g
Explanation:
At constant temperature and pressure, Using Avogadro's law
Given ,
V₁ = 2.12 L
V₂ = 3.12 L
n₁ = 0.120 moles
n₂ = ?
Using above equation as:
n₂ = 0.17660 moles
Molar mass of methane gas = 16.05 g/mol
So, Mass = Moles*Molar mass = 0.17660 * 16.05 g = 2.83 g
<u>2.83 g are in the piston.</u>
Answer:
The correct options are:
1) Pure chemical substance
2) Element.
Explanation:
each of the term is explained below:
1) <u>Mixture: </u> Since tungsten is an element in periodic table thus it is not a mixture.
2) False by definition of mixture.
3) false by definition of mixture.
4) <u>Solution:</u> Tungsten in a filament is in solid form hence solution is incorrect.
5) Since it is given in the question itself that the sample is pure hence option 'E' is correct as chemical substance is a pure substance that has a homogeneous composition and the sample in the question is given as pure.
6) <u>Compound:</u> By definition of compound it is formed by mixing 2 or more elements but since tungsten is an element that occurs independently in nature hence it is not a compound.
7) Tungsten is a element in the periodic table with atomic number 74.
Answer :Solid in bottle a is ionic, solid in bottle b is molecular and solid in bottle c is ionic.
Explanation :
Ionic compound is formed when a metal atom donates one or more electrons to a non metal. This results in the formation of a cation ( a positive ion) and an anion ( a negative ion). These ions are bonded to each other by electrostatic attraction.
The intermolecular forces in case of a an ionic compound are very strong.
The melting point of a substance depends on how strongly the molecules are attracted to each other. Stronger the forces, higher is the melting point.
Therefore ionic compounds always have very high melting points.
On the other hand, covalent compounds have weak intermolecular forces. Therefore they have low melting points.
Based on above discussion, we can classify the given compounds as follows.
a) Solid in bottle a is Ionic as it has high melting point.
b) Solid in bottle b is molecular as it has low melting point.
c) Solid in bottle c is Ionic as it has high melting point.
The net ionic equation of borax hydrolysis would be:
<span>Na2B4O7 + 7H2O-----------------> 2 NaOH + 4 H3BO3
</span>
Wherein 2 moles of sodium hydroxide and 4 moles of boric acid are produced by the hydrolysis.
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% yield = 80.719
<h3>Further explanation</h3>
Given
22.0 g of Mgl₂
25.0 g of Mg
25.0 g of l₂
Required
The percent yield
Solution
Reaction
Mg + I₂⇒ MgI₂
mol Mg = 25 g : 24.305 g/mol = 1.029
mol I₂ = 25 g : 253.809 g/mol = 0.098
Limiting reactant = I₂
Excess reactant = Mg
mol MgI₂ based on I₂, so mol MgI₂ = 0.098
Mass MgI₂ (theoretical):
= mol x MW
= 0.098 x 278.114
= 27.255 g
% yield = (actual/theoretical) x 100%
% yield = (22 / 27.255) x 100%
% yield = 80.719
