Answer:
P4Se3
Explanation:
Applying the Law of Conservation of Mass:
(133 mg total) - (45.8 mg P) = 87.2 mg Se
Dividing by the molar mass,
Phosphorus:-(45.8 mg P) / (30.97376 g P/mol) = 1.4786 mmol P
Selenium:-(87.2 mg Se) / (78.96 g Se/mol) = 1.1044 mmol Se
Divide by the smaller number of millimoles:
(1.4786 mmol P) / 1.1044 mmol = 1.339
(1.1044 mmol Se) / 1.1044 mmol = 1.000
multiply by 3, to get a whole number interger. then round to the nearest whole numbers to find the empirical formula.
Therefore the empirical formula is P4Se3
I believe B would be the answer
Answer:
D. A change of appearance
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.
Answer:
Why can leaving an interior light on in a car cause the battery to die? It drains the electrolyte from the cells
Explanation:
When light of a car is on, the electrolyte of the battery is in use and when its exhausted or drains off the battery eventually dies off