Answer:
Explanation:
We know that in 1 mole of any substances there are atoms
This number () is a constant that is known as the avogadros number
if we know how many atoms are in a mole of chromium to calculate how many there are in 11.9 moles we apply a simple rule of three
In 11.9 moles of chrome there are atoms
Answer:
Its C. electrons have both wave-like and particle-like properties
Explanation:
(2) Ca and Br (4) Na and P
Elements in the same groups shows similar chemical and physical properties. The elements having similar chemical properties are Be and Mg.
A group in periodic table is a column with elements of similar physical and chemical properties.
Both beryllium (Be) and magnesium are in group two with two valence electrons and both are metals. They have similar chemical and physical properties.
Cl is in 17th group and Ar is a 18th group element. They do not show any similarity in chemical properties. One is halogen which is unstable and the second one is noble gas which is stable. Thus no similarity.
Ca is a 2nd group element and Br is 17th group and they are different in chemical properties. One is metal and the second one is halogen with higher electronegativity.
Similarly, Na is in first group and P is 15th group element in periodic table in periodic table and does not show chemical similarities.
Therefore, the elements showing similar chemical properties are Be, Mg thus, option 1 is correct.
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atoms are made of 3 types of sub atomic particles- protons, neutrons and electrons
from these 3 particles, electrons are responsible for participating in chemical bonds. therefore chemical properties of elements are based on the number of electrons present.
valence electrons are the number of electrons in the outermost energy shell that are involved in chemical bonds.
atoms with same number of valence electrons are grouped in to columns called groups.
therefore elements of the same group have same number of valence electrons, hence similar chemical properties.
from the options given
only Be and Mg belong to the same group they both belong to group 2 with 2 valence electrons
therefore Be and Mg have similar chemical properties
answer is
1) Be and Mg
b. It is a reaction that requires heat to proceed.
c. It is a reaction that draws heat from its surroundings.
d. It is a reaction that releases heat to its surroundings.
Answer: Protons
Explanation: When determining an element identity the most important Subatomic part to look at is the number of protons in the nucleus determines the identity of an atom .
Taking into account the definition of dilution, the molarity of the diluted solution is 0.125 M.
When it is desired to prepare a less concentrated solution from a more concentrated one, it is called dilution.
Dilution is the process of reducing the concentration of solute in solution, which is accomplished by simply adding more solvent to the solution at the same amount of solute.
In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.
A dilution is mathematically expressed as:
Ci×Vi = Cf×Vf
where
In this case, you know:
Replacing in the definition of dilution:
0.15 M× 125 mL= Cf× 150 mL
Solving:
(0.15 M× 125 mL)÷ 150 mL= Cf
0.125 M= Cf
In summary, the molarity of the diluted solution is 0.125 M.
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Answer:
0.125 M
Explanation:
M₁V₁ = M₂V₂
125 mL / 1000 = 0.125 L = V₁
25 + 125 = 150 mL / 1000 = 0.150 L = V₂
0.15 M = M₁
M₁ × V₁ / V₂ = M₂
(0.15) × (0.125) / (0.150) = 0.125 M
0.125 M is the answer
Answer:
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