Answer:
B. The temperature of the water when the food sample has finished burning completely.
Explanation:
Heat or thermal energy is a form of energy that transfers from one object to another due to a temperature difference between the objects. The units for heat are joules or calories.
Calorimetry is the measurement of heat energy released or absorbed in a chemical reaction. A calorimeter is used in calorimetry. The calorimeter operates on the Law of Conservation of Energy which states that energy is never created or destroyed but is transformed from one form to another or between objects.
In food calorimetry, the energy released when food is burned is measured by recording the rise in temperature of water in a calorimeter when a given mass of a food sample is burned completely.
Energy can be calculated using the formula: Q = mc ∆T
where Q = the energy in joules or calories, m = the mass in grams, c = specific heat and ∆T = the change in temperature (final temperature - initial temperature).
The temperature of the water when the food sample has finished burning completely is taken as the final temperature of the water. The sample is allowed to smolder for sometime before recording the final water temperature. This is because the water temperature will continue to rise after the flame has gone out.
With the information given most likely in order to find the partial pressure of the gas produced you have to subtract the total air pressure in the collection flask by the atmospheric pressure since you assume that the flask started with atmospheric pressure when it was sealed and then the gas was added as the reaction took place increasing the pressure.
1.44atm-0.95 atm=0.49atm
Answer:
37.5 g NaCl
Explanation:
Step 1: Given data
- Concentration of NaCl: 15.0% m/m
- Mass of the solution: 250.0 g
Step 2: Calculate how many grams of NaCl are in 250.0 g of solution
The concentration of NaCl is 15.0% by mass, that is, there are 15.0 g of NaCl every 100 g of solution.
250.0 g Solution × 15.0 g NaCl/100 g Solution = 37.5 g NaCl
When you have a chemical reaction, it means something goes wrong with your chemicals.
