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Question: What would be a good acid-base pair from which to prepare a buffer solution whose pH is 10.3?

Answer:

South Magnetic Pole

Answer:

Green building is usually referred to as those structures and buildings  that are constructed in such a way that it helps in eliminating the negative influences such as pollution, emission of harmful gases in the environment, and in return, positively influences the ecosystem, environment and the climate in any particular place.

Explanation:

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Answer: A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the Sun, Earth, and Moon are aligned exactly with the Earth in the middle.

Explanation:

To solve this, we must know each and every concept related to solar eclipse. Therefore, the alignment of Earth, Sun and Moon during a lunar and solar eclipse is sun, earth and moon.

Solar eclipse occurs when the Moon passes between Sun and earth, casting a shadow on the Earth's surface. This shadow is divided into two parts the umbra, a cone that receives no direct sunlight, as well as the penumbra, which receives light from just a portion of the Sun's disk.

A lunar eclipse happens when the Moon transmits behind and into the shadow of the Earth. This can happen only when the earth, sun, and Moon are perfectly aligned, with Earth in the center.

Therefore, the alignment of Earth, Sun and Moon during a lunar and solar eclipse is sun, earth and moon.

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Answer:7M

Explanation:

There are different methods to express the concentration of a solution. Molarity, mole fraction, normality, molality are some examples. Here 7 mol / L is also called 7 M.

The molarity of a solution is defined as the number of moles of the solute present per litre of the solution. The molarity of a solution is generally expressed in mol / L which is its SI unit. It can also be represented as M.

The equation that is used to calculate the molarity is:

Molarity = Number of moles of the solute / Volume of the solution in litres

If the mass of the solute (w₂) of molecular mass (M₂) present in VL (or dm³) of the solution, then the molarity is given by:

M = w₂ / M₂ × V

Here the solution 7 mol per L can also be designated as 7 M.

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When KOH and Cu(NO3)2 are mixed in aqueous solution, no precipitation occurs as all ions remain solvated, hence the complete ionic equation shows no net change and is written as NR (no reaction).

When KOH (potassium hydroxide) and Cu(NO3)2 (copper(II) nitrate) are mixed in aqueous solution, a double displacement reaction occurs. KOH is a strong base and fully dissociates into K+ and OH− ions in water. Cu(NO3)2 is a soluble salt and dissociates into Cu2+ and NO3− ions.

However, no precipitate is formed in this reaction since all the ions remain in solution. Therefore, the complete ionic equation is:

K+(aq) + OH−(aq) + Cu2+(aq) + 2NO3−(aq) → K+(aq) + 2NO3−(aq) + Cu2+(aq) + OH−(aq)

After canceling the spectator ions, we are left with NR (no reaction) since there is no net change in the species present in the solution.

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Answer:

Yes

Explanation:

Bones sustain our bodies, and help shape our form. While very thin, the bones are large enough to bear all of our mass. Bones shield the organs of the body too. The skull supports the brain, and creates the face shape.

Answer:

E) 3.0x10⁻¹²

Explanation:

Ksp of Cu(OH)₂ is defined as:

Cu(OH)₂(s) ⇄ Cu²⁺(aq) + 2 OH⁻(aq)

Ksp = [Cu²⁺] [OH⁻]²

When pH is 10.1,  [OH⁻] is:

pOH = 14 - pH

pOH = 3.9

pOH = -log [OH⁻]

[OH⁻] = 1.26x10⁻⁴M

Replacing in ksp formula:

4.8x10⁻²⁰= [Cu²⁺] [1.26x10⁻⁴]²

3.0x10⁻¹² = [Cu²⁺]

That means the maximum amount of Cu²⁺ that can be in solution is 3.0x10⁻¹²M, thus, molar solubility of Cu(OH)₂ is

E) 3.0x10⁻¹²

Answer:

3.01 × 1024 × (12/5) hydrogen atoms

Explanation:

Answer:

The reaction will be driven forward (to the right), creating more 2H2CO3

Explanation:

Reactions maintain balance so if you add more to the left side of the equation, the right side of the equation will increase

Answer:a. Carbon

Explanation:

Answer:

B

Explanation:

Sunrise would be nearest the line (where B is), nighttime would be where C is, and sunset isn’t shown on the picture at all.

Answer : The correct option is, 3.75 mole [tex]N_2[/tex]

Explanation : Given,

Moles of [tex]NaN_3[/tex] = 2.5 mol

The balanced chemical equation is:

[tex]2Na+3N_2\rightarrow 2NaN_3[/tex]

From the balanced reaction we conclude that

As, 2 moles of [tex]NaN_3[/tex] produce from 3 moles of [tex]N_2[/tex]

So, 2.5 moles of [tex]NaN_3[/tex] produce from [tex]\frac{3}{2}\times 2.5=3.75[/tex] moles of [tex]N_2[/tex]

Therefore, the moles of [tex]N_2[/tex] initially present was, 3.75 moles.

Answer:

Sulphur

Explanation:

Sulphur(S) is the Sixteenth element of the periodic table and it has an electronic configuration of 2,8,6. This means it has six electrons in its outermost shell( valence electrons).

Sulphur has sixteen(16) protons which is equal to the atomic number which is also sixteen. Sulphur ends with the letter ‘r’. All the descriptions of the element are satisfied and it validates Sulphur.

Final answer:

Sulfur, with symbol 'S', is the element with 6 valence electrons and 16 protons, fitting the clue of ending with 'r'.

Explanation:

The element with 6 valence electrons and 16 protons is sulfur, which is represented by the symbol S on the periodic table. Sulfur is in group 16 of the periodic table, which means it has six electrons in its outermost shell. The ending 'r' in the question hints at sulfur's symbol 'S'. This is consistent with the periodic table where elements in group 16, like oxygen (O) and sulfur (S), indeed have six valence electrons. Sulfur is used in a variety of chemical compounds and has numerous applications in both industrial and biological processes.

Answer: Red blood cells is the name of the thing that has antigens on its surface.

Explanation:

The antigens are the molecules which are capable of stimulating an immune response in the body. Based on specific antigen on the surface of RBCs there are separate blood types A, or B. The antigens when inserted into another host organism can activate the antibodies and generate the immune response which can kill the antigens.

The antigens are present on the membranes of the red blood cells.

Answer:

Considering only specific heat,

✔ lead

would be the most ideal for use in cookware.

However, compared to the other options, lead is too

✔ dangerous and heavy.

Considering everything,

✔ aluminum

or

✔ iron

,  would make the best cookware and therefore may be the best choices overall.

Answer: Molarity of [tex]H_2SO_3[/tex] is 1.2 M.

Explanation:

To calculate the volume of acid, we use the equation given by neutralization reaction:

[tex]n_1M_1V_1=n_2M_2V_2[/tex]

where,

[tex]n_1,M_1\text{ and }V_1[/tex] are the n-factor, molarity and volume of acid which is [tex]H_2SO_3[/tex]

[tex]n_2,M_2\text{ and }V_2[/tex] are the n-factor, molarity and volume of base which is [tex]Mg(OH)_2[/tex]

We are given:

[tex]n_1=2\\M_1=?\\V_1=250mL\\n_2=2\\M_2=1.5M\\V_2=200mL[/tex]

Putting values in above equation, we get:

[tex]2\times M_1\times 250=2\times 1.5\times 200\\\\M_1=1.2M[/tex]

Thus molarity of [tex]H_2SO_3[/tex] is 1.2 M if 250 mL of the acid was used to neutralize 200 mL of 1.5 M solution of [tex]Mg(OH)_2[/tex]

Answer: Fe:Cl2 = 2:3

Explanation:

Answer:

Fe:Cl2 = 2:3

Explanation:

The answer is C.

This can be concluded by looking at the other answers and eliminating them one-by-one.

Managing (Or conserving) a natural resource means to sustain it and use it as efficiently as possible.

With this in mind, we can look and eliminate certain answers.

A is incorrect because driving a car uses gas, a natural resource. By using as much gas as possible, the resource would be wasted instead of conserved.

B is incorrect because water is a natural resource. Once again, by using this, it's wasted where it could be conserved.

C is correct because planting trees would conserve the resource; by consistently planting trees where they're cut, the chances of running out of wood decrease.

D is incorrect because both the water and the creatures that live inside it are natural resources. By dumping toxic waste, these resources are wasted where it could be conserved.

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Answer:

C

Explanation:

this is pretty self explanatory

Answer:

D) the pot

Explanation:

cus it produces thermal energy

Answer: 21 percent

Explanation:

Percentage of oxygen in the air is 21%

Given that;

Volume of air sample = 250 ml

Volume of O2 in sample = 52.5 ml

Find:

Percentage of oxygen in the air

Computation:

Percentage of oxygen in the air = [Volume of O2 in sample / Volume of air sample] × 100

Percentage of oxygen in the air = [52.5 / 250] × 100

Percentage of oxygen in the air = 21%

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Answer:

Increases, since higher the charge concentration higher the electrical force of attraction and repulsion

Answer:

B. In chemical reactions, small amounts of energy can be absorbed or released. In nuclear reactions, changes in energy are much larger.

Explanation:

I apologize if this answer is late or doesn't answer your original question, but I answered this question correctly on my quiz :)

I hope others will find this helpful! :D

Answer:

Left and right: two forces

Total: four forces

Explanation:

If it's just the forces that they are using it would be two the force of each person's hand on the other. However there is also gravity pulling down on their hand but they use another force to pull it up which you can call the normal force.

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Answer:

Left and right= two

So the total is four forces.

Answer: The pH will be 3.87

Explanation:

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration.

[tex]pH=-\log [H^+][/tex]

[tex]HCl\rightarrow H^++Cl^{-}[/tex]

According to stoichiometry,

1 mole of [tex]HCl[/tex] gives 1 mole of [tex]H^+[/tex]

Thus [tex]0.000134[/tex] moles of [tex]HCl[/tex] gives =[tex]\frac{1}{1}\times 0.000134=0.0001342[/tex] moles of [tex]H^+[/tex]

Putting in the values:

[tex]pH=-\log[0.000134][/tex]

[tex]pH=3.87[/tex]

Thus the pH will be 3.87

Answer: The pH of 0.000134 M solution of HCl is 3.873.

Explanation:

When HCl dissociates in water then it will give hydrogen and chlorine ions. The reaction will be as follows.

          [tex]HCl \rightarrow H^{+} + Cl^{-}[/tex]

This means that 1 mole of HCl is giving 1 mole of hydrogen ions on dissociation.

Hence, pH of the given solution will be calculated as follows.

                pH = [tex]-log [H^{+}][/tex]

                      = [tex]-log (0.000134)[/tex]

                      = 3.873

Thus, we can conclude that the pH of 0.000134 M solution of HCl is 3.873.

Answer:

Classification of Living Things. All living organisms are classified into groups based on very basic, shared characteristics.

Explanation:

Answer:

All living things are classified into kingdoms. Living organisms are classified based on similarities within their DNA, structure, reproduction, and appearance.

Explanation:

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