Answer:
1384 kJ/mol
Explanation:
The heat absorbed by the calorimeter is equal to the heat released due to the combustion of the organic compound. C is the total heat capacity of the calorimeter and Δt is the change in temperature from intial to final:
Q = CΔt = (3576 J°C⁻¹)(30.589°C - 25.000°C) = 19986.264 J
Extra significant figures are kept to avoid round-off errors.
We then calculate the moles of the organic compound:
(0.6654 g)(mol/46.07) = 0.0144432 mol
We then calculate the heat released per mole and convert to the proper units. (The conversion between kJ and J is infinitely precise and is not involved in the consideration of significant figures)
(19986.264 J)(1kJ/1000J) / (0.0144432 mol) = 1384 kJ/mol
A, as carbon is an atomic substance - element
Answer:
5.37 × 10⁻⁴ mol/L
Explanation:
<em>A chemist makes 660. mL of magnesium fluoride working solution by adding distilled water to 230. mL of a 0.00154 mol/L stock solution of magnesium fluoride in water. Calculate the concentration of the chemist's working solution. Round your answer to 3 significant digits.</em>
Step 1: Given data
- Initial concentration (C₁): 0.00154 mol/L
- Initial volume (V₁): 230. mL
- Final concentration (C₂): ?
- Final volume (V₂): 660. mL
Step 2: Calculate the concentration of the final solution
We want to prepare a dilute solution from a concentrated one. We can calculate the concentration of the final solution using the dilution rule.
C₁ × V₁ = C₂ × V₂
C₂ = C₁ × V₁ / V₂
C₂ = 0.00154 mol/L × 230. mL / 660. mL = 5.37 × 10⁻⁴ mol/L
It is B: Fixed volume, takes the shape of the container
Answer:
c. Forms different hydrates which have different colors
Explanation: