The atomic number of phosphorus is 15. how many electrons does it have in its 3rd shell

Standard reduction potentials for zinc(II) and copper(II) The standard reduction potential for a substance indicates how readily

givi [52]

The question is incomplete, the complete question is:

Standard reduction potentials for zinc(II) and copper(II)

The standard reduction potential for a substance indicates how readily that substance gains electrons relative to other substances at standard conditions. The more positive the reduction potential, the more easily the substance gains electrons. Consider the following:

Zn2+(aq)+2e−→Zn(s),Cu2+(aq)+2e−→Cu(s), E∘red=−0.763 V E∘red=+0.337 V

Part B

What is the standard potential, E∘cell, for this galvanic cell? Use the given standard reduction potentials in your calculation as appropriate.

Express your answer to three decimal places and include the appropriate units.

Answer:

1.100 V

Explanation:

E∘cell= E∘cathode - E∘anode

E∘cathode= +0.337 V

E∘anode= −0.763 V

E∘cell= 0.337-(-0.763)

E∘cell= 1.1V

4 0

3 years ago

The hardness of water (hardness count )is usually expressed in parts per million(by Mass) CaCO3, which is equivalent to milligra

Ksju [112]

Answer:

1.75 × 10⁻³ M

Explanation:

Given:

Hardness = 175 mg CaCO₃/L

or mass of CaCO₃ in 1 L = 175 × 10⁻³ grams

Now,

Molar mass of CaCO₃ = 40 + 12 + ( 3 × 12 ) = 100 grams/mol

The concentration of CaCO₃ = number of moles / volume

or

= (175 × 10⁻³ / 100) / 1

or

= 1.75 × 10⁻³ M

Now,

CaCO₃ ⇒ Ca²⁺ + CO₃²⁻

1.75 × 10⁻³ M 1.75 × 10⁻³ M 1.75 × 10⁻³ M

thus,

the concentration of Ca²⁺ ions in water = 1.75 × 10⁻³ M

4 0

3 years ago

10. A small gold nugget has volume of 0.87 cm3. What is its mass if the density of gold is 19.3 g/cm3?

bulgar [2K]

Answer:

16.791 grams

Explanation:

The density formula is:

$d=\frac{m}{v}$

Rearrange the formula for m, the mass. Multiply both sides of the equation by v.

$d*v=\frac{m}{v}*v$

$d*v=m$

The mass of the gold nugget can be found by multiplying the density and volume. The density is 19.3 grams per cubic centimeter and the volume is 0.87 cubic centimeters.

$d= 19.3 g/cm^3\\v-0.87 cm^3$

Substitute the values into the formula.

$m=d*v$

$m= 19.3 g/cm^3*0.87 cm^3$

Multiply. Note that the cubic centimeters, or cm³ will cancel each other out.

$m=19.3 g*0.87$

$m=16.791 g$

The mass of the gold nugget is 16.791 grams.

8 0

3 years ago

In a lab, silver nitrate,AgNO₃, is dissolved in water until no solid is observed in the container. Then, a solution of sodium ch

leva [86]

Answer:

The answer to your question is: A, C, E

Explanation:

After reading the information given, we can conclude that both reactants react to form a new solid product and another product that do not precipitate.

The reaction is:

AgNO₃ + NaCl ⇒ AgCl + NaNO₃

a. Formation of a solid indicates that a chemical reaction occurred This option is correct, precipitation indicates that a changed occurred in the solution due to a chemical reaction.

b. The initial disappearance of silver nitrate in water indicates a chemical reaction occurred No, what is happing is that silver nitrate is dissolving in water, this process is a physical change because matter do not change its nature.

c. The color change of the solution indicates a chemical reaction occurred This option is true, when a color appears suggest the formation of a new product.

d. A chemical reaction occurred when silver nitrate was added to water

This option is not correct, in this process silver nitrate is dissolving in water but it is not a chemical reaction because matter does not change is nature.

e. A chemical reaction occurred when the solutions were combined This option is true because silver nitrate and sodium chloride react to form a new product (solid formation and change in color).

f. The lack of temperature change indicates a chemical reaction didn't occur This is false, some reactions do not need a change of color to happen.

6 0

3 years ago

Please help me anyone its due today thank you !

Nina [5.8K]

true

Explanation:

Ecothermic reactiions are reactions or processes that release energy. From heat or light.

7 0

3 years ago

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