Answer:
An exothermic reaction is a chemical reaction in which energy is given out to the surroundings in the form of heat or light or even sound.
Other explanations are given below.
Explanation:
An exothermic reaction is a chemical reaction in which energy is given out to the surroundings in the form of heat or light or even sound. In exothermic reactions, the energy content of the products are lower than that of the reactants and this excess energy is therefore released as the reaction proceeds towards formation of products.
Combustion of fuel is an exothermic reaction because the process involves the release of energy in the form of heat and light to the surroundings as the reactants (usually a fuel and oxygen) which are at a higher energy state combine to give the products which are at a lower energy state (usually CO₂ and water).
An example of a fuel is the gas propane found in cooking gas. It combines with oxygen found in air to produce the heat that is used to cook our foods.
Other examples of exothermic reactions include
1.Lighting firewood: In this process, wood which is a mixture of gaseous fuels like methane and solid fuel like charcoal combine with oxygen found in air to produce carbon (iv) oxide and water vapor while releasing heating the process.
2. Lighting a match: The head of safety matches are made of potassium chlorate, mixed with sulfur, fillers and glass powder. The side of the box contains red phosphorus, binder and powdered glass. When the match is struck, the friction generates heat which causes a small amount of red phosphorus to be converted to white phosphorus, which then ignites spontaneously in air. The heat produced initiates the decomposition of potassium chlorate to give oxygen and potassium chloride. The sulfur catches fire and ignites the wood which also burns in the air to release carbon (iv) oxide an water.
3. Burning of coal: Coal is solid carbon which combines with oxygen in air when ignited to produce carbon (iv) oxide and water vapor while also releasing heat and light energy.
Answer:
0.034 M is the molarity of sodium acetate needed.
Explanation:
The pH of the buffer solution is calculated by the Henderson-Hasselbalch equation:
![pH = pK_a + \log \frac{[A^-]}{[HA]}](https://tex.z-dn.net/?f=pH%20%3D%20pK_a%20%2B%20%5Clog%20%5Cfrac%7B%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
Where:
pK_a= Negative logarithm of the dissociation constant of a weak acid
![[Ac^-]](https://tex.z-dn.net/?f=%5BAc%5E-%5D)
= Concentration of the conjugate base
[HA] = Concentration of the weak acid
According to the question:
The desired pH of the buffer solution = pH = 5.27
The pKa of acetic acid = 4.74
The molarity of acetic acid solution = [HAc] = 0.01 M
The molarity of acetate ion =![[Ac^-] = ?](https://tex.z-dn.net/?f=%5BAc%5E-%5D%20%3D%20%3F)
Using Henderson-Hasselbalch equation:
![5.27= 4.74 + \log \frac{[Ac^-]}{[0.01 M]}](https://tex.z-dn.net/?f=5.27%3D%204.74%20%2B%20%5Clog%20%5Cfrac%7B%5BAc%5E-%5D%7D%7B%5B0.01%20M%5D%7D)
![[Ac^-]=0.0339 M\approx 0.034M](https://tex.z-dn.net/?f=%5BAc%5E-%5D%3D0.0339%20M%5Capprox%200.034M)
Sodium acetate dissociates into sodium ions and acetate ions when dissolved in water.
![[Ac^-]=[Na^+]=[NaAc]= 0.034M](https://tex.z-dn.net/?f=%5BAc%5E-%5D%3D%5BNa%5E%2B%5D%3D%5BNaAc%5D%3D%200.034M)
0.034 M is the molarity of sodium acetate needed.
Answer:
Option A. Dense water floats.
Explanation:
Ocean circulation act as conveyor belt which transport warm water from the tropics towards poles from where cold water sinks to the deep ocean. It is also known as the thermohaline circulation because it is driven by salinity and temperature.
However, change in climate causing these ocean's thermohaline current to slow down because influx of cold and melting fresh water from the polar region is disrupting these circulation as influx of fresh water making the water less saline and less dense and hence it become harder to sink to deep ocean.
Note: You are calculating mass which is determine the gram(g)
You will have to cancel out the mol
(28.97 g/mol) * mol will give grams by itself
Given the mass 3.33 moles of air
28.97 g/mol * 3.33 mol = 96.47 grams
Solution: 96.5 grams
Answer:
185.49 grams of Zinc would react with 454g (1lb) of copper sulfate
Explanation:
Yo know the following balanced reaction:
CuSO₄(aq)+ Zn(s) →Cu(s) + ZnSO₄(aq)
You can see that by stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of reagents and products are part of the reaction:
- CuSO₄: 1 mole
- Zn: 1 mole
- Cu: 1 mole
- ZnSO₄: 1 mole
Being:
- Cu: 63.54 g/mole
- S: 32 g/mole
- O: 16 g/mole
- Zn: 65.37 g/mole
the molar mass of the compounds participating in the reaction is:
- CuSO₄:63.54 g/mole + 32 g/mole + 4*16 g/mole= 159.54 g/mole ≅ 160 g/mole
- Zn: 65.37 g/mole
- Cu: 63.54 g/mole
- ZnSO₄: 65.37 g/mole + 32 g/mole + 4*16 g/mole= 161.37 g/mole
Then, by stoichiometry of the reaction, the following amounts of mass of reagent and product participate in the reaction:
- CuSO₄: 1 moles* 160 g/mole= 160 g
- Zn: 1 mole* 65.37 g/mole= 65.37 g
- Cu: 1 mole* 63.54 g/mole= 63.54 g
- ZnSO₄: 1 mole* 161.37 g/mole= 161.37 g
Now you can apply the following rule of three: if 160 grams of CuSO₄ react with 65.37 grams of Zn by this reaction stoichiometry, 454 grams of CuSO₄ with how much mass of Zn will it react?
mass of Zn= 185.49 grams
<u><em>185.49 grams of Zinc would react with 454g (1lb) of copper sulfate</em></u>
