Answer:
sulfur
Explanation:
without sulfur you can not grow any food
Answer:
ΔH rx = -43.5 kJ / mol
Explanation:
In water, Xdissolves thus:
X(s) + H₂O(l) → X(aq) + H₂O(aq)
It is possible to find the heat in dissolution process using coffee cup calorimeter equation:
Q = -m×C×ΔT
<em>Where Q is heat, m is mass of solution (35.0g -density 1g/mL- + 2.20g = 37.2g), C is specific heat of solution (4.18J/g°C), and ΔT is change in temperature (26.0°C-15.0°C = 11.0°C)</em>
Replacing:
Q = -37.2g×4.18J/g°C×11.0°C
Q = -1710J = -<em>1.71kJ</em>
As enthalpy is the change in heat per mole of reaction, moles of X that reacted were:
2.20g X × (1mol / 56.0g) = <em>0.0393 moles</em>
As heat produced per 0.0393moles was -1.71kJ, heat per mole of X is:
-1.71kJ / 0.0393mol = -<em>43.5 kJ / mol = ΔH rx</em>
Answer:
Sry i am unable to see the attached picture but i hope this helps
Explanation:
There are a couple of ways to prepare a buffer solution of a specific pH. In the first method, prepare a solution with an acid and its conjugate base by dissolving the acid form of the buffer in about 60% of the volume of water required to obtain the final solution volume
Answer:
of the stock solution would be required.
Explanation:
Assume that a solution of volume 
contains a solute with a concentration of 
. The quantity 
of that solute in this solution would be:
.
For the solution that needs to be prepared, 
. The volume of this solution is 
. Calculate the quantity of the solute (magnesium chloride) in the required solution:
.
Rearrange the equation to find an expression of volume , given the concentration and quantity of the solute:
.
Concentration of the solute in the stock solution: 
.
Quantity of the solute required: 
.
Calculate the volume of the stock solution that would contain the required of the magnesium chloride solute:
.
2)A complete desktop uses an average of 200 Watt hours (Wh). This is the sum of the average consumption per hour of the computer itself (171 W), the internet modem (10 W), the printer (5 W) and the loudspeakers (20 W). Assuming that a computer is on for eight hours a day, the annual consumption comes to 600 kWh. That corresponds to CO2 emissions of about 175 kg per year, i.e. 1.75 % of the average annual emission of a Belgian.
