<span>Anthracite is also referred to as hard coal because it is so hard and pure. It is very hard and highly compacted with variety of coal that has submetallic luster. It has highest carbon content, the lowest impurities, and highest density of energy of all the coal deposits.</span>
Answer:
a. 7278 K
b. 4.542 × 10⁻³¹
Explanation:
a.
Let´s consider the following reaction.
N₂(g) + O₂(g) ⇄ 2 NO(g)
The reaction is spontaneous when:
ΔG° < 0 [1]
Let's consider a second relation:
ΔG° = ΔH° - T × ΔS° [2]
Combining [1] and [2],
ΔH° - T × ΔS° < 0
ΔH° < T × ΔS°
T > ΔH°/ΔS°
T > (180.5 × 10³ J/mol)/(24.80 J/mol.K)
T > 7278 K
b.
First, we will calculate ΔG° at 25°C + 273.15 = 298 K
ΔG° = ΔH° - T × ΔS°
ΔG° = 180.5 kJ/mol - 298 K × 24.80 × 10⁻³ kJ/mol.K
ΔG° = 173.1 kJ/mol
We can calculate the equilibrium constant using the following expression.
ΔG° = - R × T × lnK
lnK = - ΔG° / R × T
lnK = - 173.1 × 10³ J/mol / (8.314 J/mol.K) × 298 K
K = 4.542 × 10⁻³¹
The lever family and the inclined plane family.
Answer:
C. have specific jobs
Explanation:
If an organism has specialized cells, then the cells performs specific jobs.
A group of cells that performs a specific job is called tissues.
- In higher organisms, cells are specialized for specific purposes in them.
- This is to ensure that cells are optimized to carry out certain functions.
- Specialization of cells usually occurs by cellular differentiation when an organism begins to form.
Answer:
Lead(II) sulfate
Explanation:
This looks like a double displacement reaction, in which the cations change partners with the anions.
The possible products are
Pb(NO₃)₂ (aq)+ Na₂SO₄(aq) ⟶PbSO₄(?) + 2NaNO₃(?)
To predict the product, we must use the solubility rules. Two important ones for this question are:
- Salts containing Group 1 elements are soluble.
- Most sulfates are soluble, but PbSO₄ is an important exception.
Thus, NaNO₃ is soluble and PbSO₄ is the precipitate.
