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jolli1 [7]
3 years ago
7

Pls i need help with this

Chemistry
1 answer:
gregori [183]3 years ago
5 0

Answer:

C

Explanation:

A physical change is one in which no new substance is formed. The moistening of food by saliva is purely a physical change because no new substance is formed in the process.

A chemical change leads to the formation of a new substance. The action of the enzyme converts starch into sugar which means that a new substance is formed. This is a chemical change.

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Methane is a gas that easily catches fire. This statement is describing a _____.
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Calculate the standard cell potential for each of the following electrochemical cells.Standard Electrode Potentials at 25 ∘CRedu
Illusion [34]

Explanation:

We have to fhnd the standard cell potencial for this electrochemical cell:have to fi

Cd²⁺ (aq) + Mg (s) ----> Cd (s) + Mg²⁺ (aq)

We are given these electrode potentials at 25 °C.

Cd²⁺ (aq) + 2 e- ----> Cd (s) E∘(V) = - 0.40

Mg²⁺ (aq) + 2 e− ----> Mg (s) E∘(V) - 2.37

In our reaction, Cd is being reduced from i ou to solid Cd. Solid Mg is being oxidized from solid Mg to Mgd . In electrochemistry, the anode is where oxidation occurs and the cathode is where reduction occurs.

Cd²⁺ (aq) + 2 e- ----> Cd (s) Reduction = Cathode

Mg (s) ----> Mg²⁺ (aq) + 2 e− Oxidation = Anode

The standard cell potential of an electrochemicalectro will be hdard to reduction potential of the cathode minus that of the anode.²s) Cd (s) ²⁺

E°cell = E°cathode - E°anode

E°cell = -0.40 V - (- 2.37 V)

E°cell = 1.97 V

Answer: the standard cell potential of the electrochemical cell is 1.97 V.

5 0
1 year ago
A 0.100 M solution of an acid, HA, has a pH = 2.00. What is the value of the ionization constant, Ka for this acid?
EastWind [94]

Answer:

Ka=1.11x10^{-3}

Explanation:

Hello,

In this case, since the ionization of the given HA acid is:

HA\rightleftharpoons H^++A^-

The equilibrium expression is:

Ka=\frac{[H^+][A^-]}{[HA]}

Whereas the concentration of hydrogen ions is compute from the pH=

[H^+]=10^{-pH}=10^{-2.00}=0.01M

Which also equals the concentration of A^- and the in general the ionization extent, therefore, the acid ionization constant, Ka, turns out:

Ka=\frac{0.01*0.01}{0.1-0.01}\\ \\Ka=1.11x10^{-3}

Regards.

5 0
4 years ago
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