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RoseWind [281]
3 years ago
6

What is the correct answer to the following expression: (72.61 - 68.59) x 18.76? Be sure to express your answer using the correc

t number of significant figures.
Chemistry
1 answer:
ZanzabumX [31]3 years ago
6 0
To answer this expression we should follow the mathematical rule. The mathematical rule that we will follow is called BODMAS short for brackets, powers, divide, multiply, add, subtract. So, we will first solve the one in the brackets which is <span>(72.61 - 68.59) is equal to 4.02 then we will multiply this to 18.76 and the answer is 75.4152.</span>
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What is one benfit of using ph instead of molar concentrations?
puteri [66]

One benefit of using ph instead of molar concentrations is that since molarity is a rate of “ moles per liter" ,  Molarity (M) is used to measure the concentration of hydrogen ions in a solution, which is used with pH applications. ... The H+ is the molarity number, which shows the concentration of hydrogen ions in the solution.

8 0
3 years ago
A chemist designs a galvanic cell that uses these two half-reactions: half-reaction standard reduction potential (s)(aq)(aq)(l)
miv72 [106K]

Answer:

Reduction (cathode): Cu²⁺(⁺aq) + 2 e⁻ → Cu(s)  

Oxidation (anode): Zn(s) → Zn²⁺(⁺aq) + 2 e⁻        

Cu²⁺(⁺aq) + Zn(s) → Cu(s) + Zn²⁺(⁺aq)

E°cell = 1.10 V

Explanation:

<em>The half-reactions are missing, but I will propose some to show you the general procedure and then you can apply it to your equations.</em>

<em>Suppose we have the following half-reactions.</em>

<em>Cu²⁺(⁺aq) + 2 e⁻ → Cu(s)   E°red = 0.34 V</em>

<em>Zn²⁺(⁺aq) + 2 e⁻ → Zn(s)    E°red = -0.76 V</em>

<em />

To identify how to make a spontaneous cell, we need to consider the standard reduction potentials (E°red). The half-reaction with the higher E°red will occur as a reduction (in the cathode), whereas the one with the lower E°red will occur as an oxidation (in the anode).

Reduction (cathode): Cu²⁺(⁺aq) + 2 e⁻ → Cu(s)   E°red = 0.34 V

Oxidation (anode): Zn(s) → Zn²⁺(⁺aq) + 2 e⁻        E°red = -0.76 V

To get the overall equation we add both half-reactions.

Cu²⁺(⁺aq) + Zn(s) → Cu(s) + Zn²⁺(⁺aq)

The standard cell potential (E°cell) is the difference between the standard reduction potential of the cathode and the standard reduction potential of the anode.

E°cell = E°red, cat - E°red, an

E°cell = 0.34 V - (-0.76 V) = 1.10 V

Since E°cell > 0, the reaction is spontaneous.

5 0
2 years ago
Precipitation reactions always occur when two aqueous solutions are mixed (T/F)
Studentka2010 [4]

Answer: The given statement is false.

Explanation:

Precipitation reaction is defined as the chemical reaction in which two aqueous solution upon mixing together results in the formation of an insoluble solid.

For example, NaCl(aq) + AgNO_{3} \rightarrow NaNO_{3}(aq) + AgCl(s)

Here AgCl is present in solid state so, it is the precipitate.

But it is not necessarily true that two aqueous solutions will always result in the formation of a precipitate.

For example, NaCl(aq) + KNO_{3}(aq) \rightarrow KCl(aq) + NaNO_{3}(aq)

Hence, we can conclude that the statement precipitation reactions always occur when two aqueous solutions are mixed, is false.

7 0
3 years ago
Eric's father asked an engineer to survey the field behind their house. He wanted to plant some apple and pear trees there. Acco
Vsevolod [243]

Answer:

11,000 cm

Explanation:

Step 1: Given data

Width of the field (w): 17 meters

Length of the field (l): 38 meters

Step 2: Calculate the perimeter of the field

The field is a rectangle. We can find its perimeter (P) by adding its sides.

P = 2 × w + 2 × l = 2 × 17 m + 2 × 38 m = 110 m

Step 3: Convert the perimeter to centimeters

We will use the relationship 1 m = 100 cm.

110 m × (100 cm/1 m) = 11,000 cm

8 0
3 years ago
Based on solubility rules what ions in water might interfere with the analysis of calcium ions by precipitation of calcium carbo
Pavlova-9 [17]
First, we must know what happens in the precipitation reaction. This type of reaction is a double replacement reactions. It is consists of two reactant compounds which interchange cations and anions to form two products. One of the products is an insoluble solid called a precipitate. For the precipitation of CaCO₃, there are two consecutive reactions involved:

1. Slaking of quicklime, CaO
    CaO + H₂O ⇒ Ca(OH)₂

2. Precipitation
    Ca(OH)₂ + CO₂ ⇒ CaCO₃ + H₂O

The ions that make up the H₂O molecule are H⁺ and OH⁻. According to solubility rules, the cation (positively charged ion) is likely to be attracted to an anion (negatively charged ion). Together, they form an ionic bond. This type of bond is when there is a complete transfer of electrons between the two. The Ca²⁺ cation lacks 2 electrons, while the anion OH⁻ has an excess 1 electron. In order to be stable, 1 Ca²⁺ ion and 2 OH⁻ ions must combine.

Therefore, the answer is OH⁻ ion.
6 0
3 years ago
Read 2 more answers
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