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:
Explanation:
3. The number of electrons and neutrons in an atom are 13 and 14, respectively. Find out the mass number, atomic number, valency, and symbol of the element.
For a neutral atom. number of protons =number of electrons=13
so since atomic number is the number of protons =13
mass number = protons + neutons =14+13 = 27
atomic number 13 is Aluminum (AL-(see periodic table)
The electronic structure for 13 electrons is 1s2s2p63s23p1
so Al has 3 electrons which are VALIENT and can react and when it loses the 3 it will have CHARGE OF +3
<u>Answer:</u> 2.00 atm
<u>Explanation:</u>
The gas is kept under the same temperature in this problem. Assuming the amount of gas is constant, we can apply the Boyle's law.
The Boyle's law equation,
P₁V₁ = P₂V ₂
Plug in the values,
1.00 atm x 4.0 L = P₂ x 2.0 L
Simplify,
4.00 atm L = 2 P₂ L
Now flip the equation,
2 P₂ L = 4.00 atm L
Dividing both sides by 2 we get,
P₂ = 2.00 atm
Answer:
Explanation:
Carbon (coke) burns in air to form carbon dioxide gas.
(i) C(s) + O2 ↑= CO2 ↑
Density is defined as the ratio of mass to the volume.
Density = 
(1)
Mass of water = 10 grams
Mass of acetone = 10 grams
Density of water = 1 
Density of acetone = 0.7857
Put the value of density of water and its mass in equation (1)
1 = 
Volume of water = 10 
Put the value of density of acetone and its mass in equation (1)
0.7857 =
Volume of acetone = 12.72
Thus, volume of acetone is more than volume of water because the density of acetone is lower.
