Answer:
13.4g
Explanation:
we know that:
1 mole = 6.02 × 10²³ atoms
make the unknown number of moles = x
x = 7.1 × 10²² atoms
putting them both together:
1 mole = 6.02 × 10²³ atoms
x = 7.1 × 10²² atoms
Cross multiply:
6.02 × 10²³ x = 7.1 × 10²²
divide both sides by 6.02 × 10²³
we now have the number of moles of Al₂CO₃
to calculate the grams (mass):
add up all of the atomic masses of Al₂CO₃ to calculate relative formula mass:
(27 × 2) + 12 + (16 × 3) = 114
the grams (mass) of Al₂CO₃:
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.
All of the various light
waves move with the same speed, a value
<span>abbreviated (c) equal to 3.00
× 108 m/s. The frequency ([1]) that light waves
pass a given point is</span>
measured in waves/second or
simply ‘per second’ (1/s).
the frequency of the wave f =
(3.00 × 10^8 m/s)/ 2.340 m
<span>f = 1.28x10^8 Hz</span>
Answer:
If the volume of a container is decreased, the temperature decreases, which means that the volume of a gas is directly proportional to its temperature
Answer:
Explanation:
3
Explanation:
The reaction expression is given as:
Al(OH)₃ + HNO₃ → H₂O + Al(NO₃)₃
To solve this problem, let us assign coefficient a,b,c and d to each specie;
aAl(OH)₃ + bHNO₃ → cH₂O + dAl(NO₃)₃
Conserving Al : a = d
O: 3a + 3b = c + 9d
H: 3a + b = 2c
N: b = 3d
let a = 1 , d = 1, b = 3 , c = 3
Multiply through by 3;
a = 1, b = 3, c = 3 and d = 1
Al(OH)₃ + 3HNO₃ → 3H₂O + Al(NO₃)₃
