Answer:
This question is incomplete
Explanation:
This question is incomplete, however, element R and element Q having the same number of valence electrons means they belong to the same group in the periodic table which is the reason for there similar chemical behavior (as elements in the same group tend to have the same chemical properties).
Element R having fewer energy level (or electron shell) than element Q shows element R has fewer number of electrons than element Q and can be found earlier in the periodic table (or group in particular) when compared to element Q
Answer:
Change occur in heat energy.
Explanation:
Change occur in the heat energy of molecules during condensation process. The molecules of gas releases its heat energy and converted into liquid state. With this heat energy, they are active and escape from each other but when the heat energy is removed from them, the attractive forces between these gas molecules are formed which convert them into liquid state so change in heat energy occur in the condensation process.
Answer:
Δ S = 26.2 J/K
Explanation:
The change in entropy can be calculated from the formula -
Δ S = m Cp ln ( T₂ / T₁ )
Where ,
Δ S = change in entropy
m = mass = 2.00 kg
Cp =specific heat of lead is 130 J / (kg ∙ K) .
T₂ = final temperature 10.0°C + 273 = 283 K
T₁ = initial temperature , 40.0°C + 273 = 313 K
Applying the above formula ,
The change in entropy is calculated as ,
ΔS = m Cp ln ( T₂ / T₁ ) = (2.00 )( 130 ) ln( 283 K / 313 K )
ΔS = 26.2 J/K
Answer:
74mL
Explanation:
Given parameters:
Molar mass of citric acid = 192g/mol
Molar mass of baking soda = 84g/mol
Concentration of citric acid = 0.8M
Mass of baking powder = 15g
Unknown parameters:
Volume of citric acid = ?
Solution
Equation of the reaction:
C₆H₈O₇ + 3NaHCO₃ → Na₃C₆H₅O₇ + 3H₂O + 3CO₂
Procedure:
- We work from the known parameters to the unknown. From the statement of the problem, we can approach the solution from the parameters of the baking powder.
- From the baking powder, we can establish a molar relationship between the two reactants. We employ the mole concept in this regard.
- We find the number of moles of the baking powder that went into the reaction using the expression below:
Number of moles = 
Number of moles = 
= 0.179mole
- From the equation of the reaction, we can find the number of moles of the citric acid:
3 moles of baking powder reacted with 1 mole of citric acid
0.179 moles of baking powder would react with 
:
This yields 0.059mole of citric acid
- To find the volume of the citric acid, we use the mole expression below:
Volume of citric acid = 
Volume of citric acid = 
= 0.074L
Expressing in mL gives 74mL
