Explanation:
Na represents the neutral element; Sodium. Because of it's atomic number of 11, It has 11 electrons.
Na+ on the other hand represents a cation. The sodium ion has lost an electron, hence the total number of electrons it has = 10.
The K and L shells each have maximum number of electrons they can accommodate. This is given by the formular; 2n^2
K shell = 2 (1)^2 = 2 electrons
L shell = 2 (2)^2 = 8 electrons
Seeing as Na+ has 10 electrons, It completely filled the K and L shells ( 2 + 8 = 10 )
Complete question is;
When the concentrations of reactant molecules are increased, the rate of reaction increases. The best explanation for this phenomenon is that as the reactant concentration increases,
A)the average kinetic energy of molecules increases.
B)the frequency of molecular collisions increases.
C)the rate constant increases.
D)the activation energy increases.
E)the order of reaction increases.
Answer:
B) The frequency of molecular collisions increases.
Explanation:
When we increase number of reactant molecules, the effective collision between the reactant molecules will form a product which also increases. As a result, the overall rate of the reaction will also increase which means the frequency of the molecular collision will also increase as well.
Thus, the correct answer is Option B
Answer:
1) conduction
2) Radiation
Explanation:
Conduction is a mode of heat transfer by which heat energy is transferred through a material, the average position of the particles of the material remaining the same.
Radiation is a process of heat transfer by which heat is transferred from a hotter to a cooler point without any intervening medium.
The pan used to fry the egg is a conductor of heat hence heat can pass through it by conduction thereby enabling the eggs to cook.
Heat can travel without an intervening medium hence Zoe feels hot near the stove. This ability of the heat to travel without an intervening medium is called radiation.
The freezing point depression of the solution or pure substance that is added with the solvent is calculated through the equation,
ΔTf = Kfm
where ΔT is the freezing point depression, Kf is the constant for water given to be -1.86°C/m and m is the molality of the solution.
Molality is calculated through the equation,
m = number of moles solute/ kg of solvent
Calculation of molality is shown below.
m = (21.5 g C6H12O6)(1 mol/180 g) / (0.255 kg)
m = 0.468 molal
The freezing point depression is then,
ΔTf = (-1.86°C/m)(0.468 m) = -0.87°C
<em>Answer: -0.87°C</em>
