Answer:
Q = 768.47 J
Explanation:
Given that,
Mass of the metal, m = 25 g
Initial temperature, T₁ = 21.0 ºC
Final temperature, T₂ = 80.0 ºC
The specific heat of the metal is 0.521 J/gºC.
We know that the heat released due to the change in temperature is given by :
Hence, 768.47 J of heat energy will be needed.
Answer:
2H2O2(aq)→ 2H2O(l) O2(g) : The oxidation number of oxygen for each compound is -1, -2, 0
Explanation:
In peroxides the oxidation state of oxygen is -1, since one oxygen bonds to the other oxygen and a hydrogen and the bound oxygen captures the electron of the remaining hydrogen. Through a scheme would be
H --- O --- O --- H
We remember that oxygen needs two electrons to get to have the configuration of the nearest noble gas (Lewis octet rule). In Peroxides, the oxygen is linked by covalent bonds. If we take it strictly, peroxide is a grouping of two oxygen, having the whole valence -2. which is why it is usually said that it is when oxygen has a valence -1
As we said the oxidation state is -2, the one that appears in the water molecule, since Hydrogen acts with valence +1 and it is 2 atoms that give up electrons to compensate for oxygen.
In the O2 it acts with valence 0 since we talk about gas in its elementary state. All diatomic molecules in their elemental state, generally gases or metals in solid state, act with a valence of 0.
Answer:
The calculations are in the explanation below.
The <em>steps </em>are:
- 1. Using a graduated pipette, accurately take 25mL of the 12.0M stock solution.
- 2. Pour the 25mL of stock solution into a 100 mL volumetric flask
- 3. Add distilled water up to the mark
- 4. Cap the flask with the stopper
- 5. Stirr by gently rotating the flask.
Explanation:
To make 100 mililiter of the 3.0M solution of sulfuric acid, first you must calculate the volume of the 12.0M stock solution that contains the same number of moles as the diluted solution.
For that, you use the dilution formula:
- number of moles = C₁V₁ = C₂V2
- V₁ = 3.0M × 100mL/12.0M = 25mL
Then, the steps are:
1. Using a graduated pipette, accurately take 25mL of the 12.0M stock solution.
2. Pour the 25mL of stock solution into a 100 mL volumetric flask
3. Add distilled water up to the mark
4. Cap the flask with the stopper
5. Stirr by gently rotating the flask.
