<h3>
Answer:</h3>
28.96 kJ/°C
<h3>
Explanation:</h3>
We are given;
- Enthalpy change (ΔH) = −3226.7 kJ/mol
- The reaction is exothermic since the heat change is negative;
- Mass of benzoic acid = 3.1007 g
- Temperature change (21.84°C to 24.67°C) = 2.83°C
We are required to find the heat capacity of benzoic acid;
<h3>Step 1: Moles of benzoic acid </h3>
Moles = Mass ÷ molar mass
Molar mass of benzoic = 122.12 g/mol
Therefore;
Moles = 3.1007 g ÷ 122.12 g/mol
= 0.0254 moles
<h3>Step 2: Determine the specific heat capacity </h3>
Heat change for 1 mole = 3226.7 kJ
Moles of Benzoic acid = 0.0254 moles
But;
Specific heat capacity × ΔT = Moles × Heat change
cΔT = nΔH
Therefore;
Specific heat capacity,c = nΔH ÷ ΔT
= (3226.7 kJ × 0.0254 moles) ÷ 2.83°C
= 28.96 kJ/°C
Therefore, the specific heat capacity of benzoic acid is 28.96 kJ/°C
Answer:
1.457*10^-8 grams
Explanation:
First we want to find the molar concentration of MgF2. We can do this by dividing 0.016 (the solubility in grams of MgCl2 in a litre of water) by its molar mass (approx. 62.3 grams). Thus, the molar solubility of MgF2 is 2.57*10^-4 M.
Next, we must calculate the Ksp of MgF2. The equilibrium expression is:
MgF2⇄Mg+2F
Thus
This means that, in equilibrium, there are 2.57*10^-4 M of and 5.136*10^-4 M of
Plugging in the above information, our Ksp for MgF2 is approximately 6.78*10^-11
Next we will need to use the RICE table. Since there is already 0.29M of NaF dissolved, there is initially 0.29M of .
R: MgF2 ⇄ +2
I: N/A 0 0.29M
C: N/A +x +x
--------------------------------------------
E: N/A x 0.29+x
To make calculations easier, we will assume that 0.29+x≈0.29
This means that Ksp=0.29x=6.78*10^-11
Therefore, x≈2.338*10^-10M
Multiply that by 62.3 and we get around 1.457*10^-8 grams.
Answer:
drought
Explanation:
droughts are long periods without water
Answer: A
0 degrees and 101 kPa are the conditions that describe the standard temperature and pressure. When expressed in K, the standard temperature 0 degrees equals 273.5 K. Also the standard pressure 101 kPa equals 760 mmHg or 1 Atm.
Answer :
The parent and daughter concentrations (in percentages) is, 60 % and 40 % respectively.
The age of rock is
Explanation :
First we have to calculate the parent and daughter concentrations (in percentages).
and,
As we know that, the half-life of uranium-238 = years
Now we have to calculate the rate constant, we use the formula :
Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant =
t = time passed by the sample = ?
a = initial amount of the reactant = 3 g
a - x = amount left after decay process = 1.8 g
Now put all the given values in above equation, we get
Therefore, the age of rock is