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Juli2301 [7.4K]
2 years ago
15

Whats principle of Aristotle's do scientist use today

Chemistry
1 answer:
Darina [25.2K]2 years ago
6 0
His observation and census.
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Calculate δ h for the reaction:no (g) + o2 (g) ↔ no2 (g). given: 2o3(g) ↔ 3o2(g) δh=-426 kj o2(g) ↔ 2o(g) δh=+ 490 kj no(g) + o3
maks197457 [2]
To calculate the <span>δ h, we must balance first the reaction: 

NO + 0.5O2 -----> NO2

Then we write all the reactions,

2O3 -----> 3O2    </span><span>δ h = -426 kj        eq. (1)

O2 -----> 2O    </span><span>δ h = 490 kj             eq. (2)

NO + O3 -----> NO2 + O2    </span><span>δ h = -200 kj          eq. (3)


We divide eq. (1) by 2, we get

</span>O3 -----> 1.5O2    δ h = -213  kj             eq. (4)

Then, we subtract eq. (3) by eq. (4) 

NO + O3 ----->  NO2 + O2   δ h = -200 kj
-       (O3 -----> 1.5 O2         δ h = -213  kj)
NO -----> NO2 - 0.5O2        δ h = 13  kj               eq. (5)


eq. (2) divided by -2. (Note: Dividing or multiplying by negative number reverses the reaction)

O -----> 0.5O2  <span>δ h = -245  kj         eq. (6)
</span>
Add eq. (6) to eq. (5), we get

NO -----> NO2 - 0.5O2        δ h = 13  kj 
+  O -----> 0.5O2                 δ h = -245  kj
NO + O ----> NO2               δ h = -232 kj

<em>ANSWER:</em> <em>NO + O ----> NO2               δ h = -232 kj</em>


4 0
3 years ago
A 155.0 g piece of copper at 128 oC is dropped into 250.0 g of water at 17.9 oC. (The specific heat of copper is 0.385 J/goC.) C
Mamont248 [21]

Answer:

T_{eq}=23.85^oC

Explanation:

Hello,

In this case, as the copper's heat loss is gained by the water, the following energetic relationship is:

\Delta H_{Cu}=-\Delta H_{H_2O}

Therefore the equilibrium temperature shows up as:

m_{Cu}Cp_{Cu}(T_{Cu}-T{eq}) = m_{H_2O}Cp_{H_2O}(T_{eq}-T_{H_2O})\\\\T_{eq}=\frac{m_{Cu}Cp_{Cu}T_{Cu}-m_{H_2O}Cp_{H_2O}T_{H_2O}}{m_{Cu}Cp_{Cu}-m_{H_2O}Cp_{H_2O}} \\

Thus, by knowing that water's heat capacity is 4.18J/g°C, one obtains:

T_{eq}=\frac{155.0g*0.385\frac{J}{g^oC}*128^oC+250.0g*4.18\frac{J}{g^oC}*17.9^oC}{155.0g*0.385\frac{J}{g^oC}+250.0g*4.18\frac{J}{g^oC}}=23.85^oC

Best regards.

6 0
3 years ago
Read 2 more answers
What must happen in a chemical reaction?
klasskru [66]
The anwser is atoms are destroyed
6 0
3 years ago
In an aqueous solution that has not reached the saturation point, why won't the ions bond to create mineral crystals?
Dominik [7]
In an aqueous solution that has not reached the saturation, the ions do not bond to create mineral crystals the motion of the ions that are dissolved would keep them from bonding. The ions creates temporary bonds to the partial charge present in the water molecules which will not allow for the ions to form a compound.
8 0
3 years ago
1. What first prompted James Watson's desire to solve the structure of DNA?
GuDViN [60]

<u>Explanation:</u>

1. It was as a result of a blurry picture of the DNA eye made by scientist, Maurice Wilkins, this glimpse of the DNA made James Watson even more curious about the DNA.

2. They were considered an unlikely pair due to their age difference of about 12 years. Seemed unlikely because there was a 12 year age difference. However, they are considered a perfect team to solve the structure since James Watson has a strong background in biology, while Francis Crick is an expert in x-ray crystallography.

3. Other researchers also racing to find the structure include;

  • Rosalind Franklin, and
  • Linus Pauling.

4. It is important to note that the data provided by Rosalind Franklin enabled Watson and Crick to better understand the chains that make up the DNA.

5. In the year, 1962 they were awarded the Nobel prize in Physiology and Medicine. They were only three recipients because at the time they were the only living early contributors to the study of the DNA.

5 0
3 years ago
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