Answer:
a usually reversible change in the physical properties of a substance, as size or shape
<u>For example:</u>
Freezing a liquid is a physical change.
Answer:
Explanation:
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In this case, since the first law of thermodynamics allows us to understand how the energy behaves when heat and work are involved during a process, we can mathematically define it as:
Whereas Q is the heat added to the system, W the work done by the system and ΔU the change in the internal energy, we can notice that since 97.0 J of work are done on the system it would be negative and the given off heat is also heat due to the used convention; therefore the change in its internal energy turns out:
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Answer:
86.2 g/mol
Explanation:
Before you can find the molar mass, you first need to calculate the number of moles of the gas. To find this value, you need to use the Ideal Gas Law:
PV = nRT
In this equation,
-----> P = pressure (mmHg)
-----> V = volume (L)
-----> n = moles
-----> R = Ideal Gas constant (62.36 L*mmHg/mol*K)
-----> T = temperature (K)
After you convert the volume from mL to L and the temperature from Celsius to Kelvin, you can use the equation to find the moles.
P = 760 mmHg R = 62.36 L*mmHg/mol*K
V = 250 mL / 1,000 = 0.250 L T = 20 °C + 273.15 = 293.15 K
n = ? moles
PV = nRT
(760 mmHg)(0.250 L) = n(62.36 L*mmHg/mol*K)(293.15 K)
190 = n(18280.834)
0.0104 = n
The molar mass represents the mass (g) of the gas per every 1 mole. Since you have been given a mass and mole value, you can set up a proportion to determine the molar mass.
<----- Proportion
<----- Cross-multiply
<----- Divide both sides by 0.0104
Answer:
30.11 × 10²³ atoms
Explanation:
Given data:
Number of moles of gold = 5 mol
Number of atoms = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
5 mol × 6.022 × 10²³ atoms /1 mol
30.11 × 10²³ atoms