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:
1) The correct step in the scientific method that Victor did is Construct a hypothesis.
2) Given mass and density, volume is calculated as mass divided by density.
Explanation:
1) Before doing the assay and make a graph with the results obtained, Victor should think what he wants to prove, so he should make a hypoythesis to test with the assay.
2) The formula of density is
density = mass/volume ⇒ density x volume = mass ⇒ volume = mass/density.
Answer:
The final pressure of a gas is inversely proportional to the volume change and directly proportional to temperature
Explanation:
Given
Required
Interpret
Multiply both sides by T1
Divide both sides by V1
This can be rewritten as:
In the above expression; k is a constant of proportionality.
So, the equation can be written as variation as follows:
To interpret:
<em>P varies directly to T (the numerator) and inversely to V (the denominator).</em>
<em></em>
<span>1.16 moles/liter
The equation for freezing point depression in an ideal solution is
ΔTF = KF * b * i
where
ΔTF = depression in freezing point, defined as TF (pure) ⒠TF (solution). So in this case ΔTF = 2.15
KF = cryoscopic constant of the solvent (given as 1.86 âc/m)
b = molality of solute
i = van 't Hoff factor (number of ions of solute produced per molecule of solute). For glucose, that will be 1.
Solving for b, we get
ΔTF = KF * b * i
ΔTF/KF = b * i
ΔTF/(KF*i) = b
And substuting known values.
ΔTF/(KF*i) = b
2.15âc/(1.86âc/m * 1) = b
2.15/(1.86 1/m) = b
1.155913978 m = b
So the molarity of the solution is 1.16 moles/liter to 3 significant figures.</span>
Answer:
Ligands
Explanation:
Ligands are small molecules that transmit signals in between or within cells. Ligands exert their effects by binding to cellular proteins called receptors.
