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Greeley [361]
3 years ago
11

Your teacher asks you to follow the instructions in a lab to produce several known chemical reactions. During these procedures,

you are required to record any observations that suggest chemical reactions have occurred. Which of these list of observations best describes evidence of chemical reactions?
Chemistry
1 answer:
vova2212 [387]3 years ago
3 0

Answer:

There are five evidences that tell whether a chemical change has occurred. These are change of color, change of odor, change in temperature or energy, formation of gas and formation of a precipitate.

Explanation:

Chemical Change- This is a type of chemical reaction which occurs when the properties of one or more atoms change and results into a<u> newly formed substance. </u>

Let's have a further discussion of the evidences.

1. Change of Color- Color change is caused by the combination of two or more substance with different molecular structures. A popular example of this is the Statue of the Liberty, which is made of copper plates. Due to the exposure of copper to elements like water, it changed color.

2. Change of Odor- This can be best presented with rotting food. During the rotting process, the food undergoes a chemical reaction. The result is a rotten smell.

3. Change in Temperature or Energy- An example of this is the burning of wood. Its change is considered non-reversible.

4. Formation of Gas- This can be best presented with the cake batter (the one being used to make cakes or pancakes). The batter rises which means it is forming gas. This is caused by the reaction of the baking soda and the acid.

5. Formation of a Precipitate- This occurs when two soluble salts combine and their outcome is an insoluble salt (this is the precipitate).

Take note that if any of these evidences occur, then there's definitely a chemical reaction.

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What is the purpose of galvanization?​
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A buffer consists of 0.45 M CH3COOH (acetic acid) and 0.35 M CH3COONa. The Ka of acetic acid is 1.8 x 10-5 . a) Calculate the pH
Zigmanuir [339]

Answer:

A) pH of Buffer solution = 4.59

B) pH after 5.0 ml of 2.0 M NaOH have been added to 400 ml of the original    buffer solution = 4.65

Explanation:

This  is the Henderson-Hasselbalch Equation:

 pH = pKa + log\frac{[conjugate base]}{[acid]}

to calculate the pH of the following Buffer solutions.

8 0
3 years ago
Using the data in the chart, which of the following would be a correct analysis?
Temka [501]

Answer:  A.  Inverse relationship

Explanation:  A plot illustrates that as x increases, y decreases - an inverse relationship.

6 0
3 years ago
Complete the first row in the table by filling in the missing information about a system at equilibrium.
enot [183]

Answer:

Q= K_{eq}

Explanation:

Equilibrium system: It is defined as that condition when the rate of forward reaction is equal to rate of backward reaction.

It is also defined as that condition concentration of reactantsx and concentrations of products are constant .

Suppose a reaction

aA+bB\leftrightharpoons cC+dD

Equilibrium constant,K_c=\frac{concentartion\;of\;products}{concentration;of;reactants}

Equilibrium constant,K_c=\frac{C^c\cdot D^d}{A^a\cdot B^b}

When the reaction is not in equilibrium then reaction constant

Q_c=\frac{C^c\cdot D^d}{A^a\cdot B^b}

When the reaction is in equilibrium then the equilibrium constant is equal to reaction constant

Hence,Q = K_c

When Q < K then the concentrations of reactants are greater than the concentrations of products.

When Q > K then the concentrations of products are greater than the concentration of reactants.

Answer : Q= K_{eq}

3 0
3 years ago
Read 2 more answers
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