Answer:
T½ = 16hours
Explanation:
Final mass (N) = 10g
Initial mass (No) = 20g
Time (t) = 16hours
T½ = ?
T½ = In2 / λ
But λ = ?
In(N/No) = -λt
In(10/20) = -(λ * 16)
In(0.5) = -16λ
-0.693 = -16λ
λ = 0.693 / 16
λ = 0.0433
Note : λ is known as the disintegration constant
T½ = In2 / λ
T½ = 0.693 / 0.0433
T½ = 16hours
The half-life of the sample is 16hours
Answer:
Aluminium atoms = 4.13 *10^22 aluminium atoms
The correct answer is E
Explanation:
Step 1: Data given
Mass of Al2O3 = 3.50 grams
Molar mass of Al2O3 = 101.96 g/mol
Number of Avogadro = 6.022 * 10^23 /mol
Step 2: Calculate moles Al2O3
Moles Al2O3 = mass Al2O3 / molar mass Al2O3
Moles Al2O3 = 3.50 grams / 101.96 g/mol
Moles Al2O3 = 0.0343 moles
Step 3: Calculate moles Aluminium
In 1 mol Al2O3 we have 2 moles Al
in 0.0343 moles Al2O3 we have 2*0.0343 = 0.0686 moles Al
Step 4: Calculate aluminium atoms
Aluminium atoms = moles aluminium * Number of Avogadro
Aluminium atoms = 0.0686 * 6.022 * 10^23
Aluminium atoms = 4.13 *10^22 aluminium atoms
The correct answer is E
There can be three possible answers to this question: the amount of moles of SO₂ gas needed to react with 6.41 mol H₂S, and the amount of S and H₂O gas produced.
Amount of SO₂:
6.41 mol H₂S (1 mol SO₂/2 mol 2 mol H₂S) = <em>3.205 moles SO₂ gas</em>
Amount of S:
6.41 mol H₂S (3 mol S/2 mol 2 mol H₂S) =<em> 9.615 moles S solid</em>
Amount of H₂O:
6.41 mol H₂S (2 mol H₂O/2 mol 2 mol H₂S) = <em>6.41 moles H₂O gas</em>
Answer : Option 3) Wave/Particle duality.
Explanation : The experiment on discovery of photoelectric effect revealed about the photoelectrons of light that can behave as particle or waves.
The photoelectric effect is observed when the emission of electrons or other free carriers occurs on shining a light radiation on a material. The electrons emitted from this can be called photo electrons. These photoelectrons may behave as wave or particle in duality which holds that light and matter exhibit properties of both waves and of particles.
Answer:
Energy transfers from the metal to the water and calorimeter until they are all at room temperature.
Explanation:
CHECK THE COMPLETE QUESTION BELOW;
A metal sample is heated and placed into the water in a calorimeter at room temperature. Which statement best describes how the calorimeter can be used to determine the specific heat capacity of the metal sample?
Energy transfers to the metal from the water and calorimeter until they are all at room temperature
. Energy transfers from the metal to the water and calorimeter until they are all at room temperature.
Energy transfers to the metal from the water and calorimeter until they all reach a single temperature.
Energy transfers from the metal to the water and calorimeter until they all reach a single temperature.
EXPLANATION;
Using calorimeter to determine the specific heat capacity of the metal sample can be associated to the theory of conservation of energy because heat which is a form of energy is been transfer of heat between the metal to the water and the calorimeter, this process will proceed till single temperature is attained.
The change in the amount of temperature of the water in the calorimeter is measured in order to get the difference in heat change of the calorimeter water.
CHANGE IN HEAT CAN BE CALCULATED USING THE FORMULA.
Q = cmΔT where Q is the change in heat , c is the specific heat capacity and ΔT is the change in temperature
