Which one please help!!

Answer:

True? The don't stay exactly still i dont think, but i'd say true.

Explanation:

Answer:

TRUE

Explanation:

In a solid, atoms are packed tightly together and move very slowly. In fact, they do not flow at all: they simply vibrate back and forth.

Key words vibrate, not movement.

Correct me if I'm wrong of course

Answer:

each planet has a different force of gravity

Explanation:

Weight = mass× gravity

As gravity changes from place to place and also from planet to planet so weight changes.

Answer: metal and salt water

Explanation: salt starts to brake down metal and metal is everywhere in the ocean hope this helps

Answer:

baking a cake.

Explanation:

baking a cake is an example of a chemical reaction that happens daily because a new substance is forming when the cake is being baked. hope this helps! :)

Answer:

5.44 moles of nitrogen required.

Explanation:

Given data:

Number of moles of NH₃ = 10.88 mol

Moles of N₂ required = ?

Solution:

Chemical equation:

N₂ +  3H₂         →       2NH₃

Now we will compare the moles nitrogen and hydrogen.

               NH₃          :           N₂

                 2             :           1

               10.88        :         1/2×10.88 = 5.44mol

5.44 moles of nitrogen required.

Answer:

A

Explanation:

Answer:

312.5

Explanation:

The volume of 2.050 M copper(II) nitrate that must be diluted with water to prepare 750.0 mL of a 0.8543 M solution is equal to 312.5 ml.

Volume is defined as a three dimensional quantity that is used to measure the capacity of a solid shape.

It is also defined as the measure of the capacity that an object holds.

M1V1 = M2V2

Here M1 = 2.050 M

        M2 = 0.8543 M

        V2 = 750 ml

So, V1 = M2V2 / V1

          = 0.8546 M x 750 ml / 2.050

          = 312.5 ml

Thus, the  volume of 2.050 M copper(II) nitrate that must be diluted with water to prepare 750.0 mL of a 0.8543 M solution is equal to 312.5 ml.

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Explanation:

CH4+8/2Cl2—>CCl4+4HCl

that is,1molecule of methane+8/2 molecules of dichlorine—>1molecule of carbon tetrachloride+4molecules of hydrogen chloride

The solubility of lead chromate : s= 5.29 x 10⁻⁷ mol/L

Given

Ksp  for PbCl,=2.8x10*-13 mole/dmº

PbCrO4

Required

The solubility

Solution

P b C r O ₄ ( s ) ⇌ P b²⁺( a q) +C r O ₄ ⁻²( a q )

s                     s               s

s= solubility

Ksp P b C r O ₄  = s²

K s p  = [ P b ²⁺] [C r O ₄ ⁻² ]= 2.8x10⁻¹³

s = √2.8x10⁻¹³

s= 5.29 x 10⁻⁷ mol/L

Mendeleev arranged the known elements in his periodic table according to atomic number (option D).

Periodic table is a tabular chart of the chemical elements according to their atomic numbers so that elements with similar properties are in the same group (column).

The chemical elements are organized by atomic number, from the element with the lowest atomic number, hydrogen, to the element with the highest atomic number, oganesson.

Dmitri Mendeleev is the Russian scientist that formulated the periodic table of chemical elements and arranged them in order of increasing atomic number.

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Answer: C.

Explanation:

according to atomic mass

Answer:

B

Explanation:

Answer:

[tex]PNCl_2[/tex]

Explanation:

Hello!

In this case, when determining empirical formulas by knowing the by-mass percent, we first must assume the percentages as masses so we can compute the moles of each element:

[tex]n_P=\frac{26.73g}{30.97g/mol}=0.863mol\\\\n_N=\frac{12.09g}{14.01g/mol}=0.863mol\\\\n_C_l=\frac{61.18g}{35.45g/mol}=1.726mol[/tex]

Now, for the determination of the subscript of each element in the empirical formula, we divide the moles by the fewest moles (P or N):

[tex]P=\frac{0.863mol}{0.863mol}=1\\\\N= \frac{0.863mol}{0.863mol}=1\\\\Cl=\frac{1.726mol}{0.863mol}2[/tex]

Thus, the empirical formula is:

[tex]PNCl_2[/tex]

Regards!

Answer:

two electrons.... oxygen needs two electrons to attain stability

Answer:

Gallium

Explanation:

Answer:

Gallium

Explanation:

Answer:

Yes

Explanation:

A molecule has a center of symmetry when, for any atom in the molecule, an identical atom exists diametrically opposite this center an equal distance from it(Wikipedia).

A center of symmetry is said to exist in a molecule when reflection of all parts of the molecule through the center of symmetry produces an indistinguishable configuration(Housecroeft and Sharpe,2012)

Obviously, the Cl2 molecule has a center of symmetry, hence it is symmetrical. Reflection of the molecules through its center of symmetry produces an indistinguishable configuration.

Answer:

powder

Explanation:

Between the powder and marble chips, the powder will have a larger surface area.

For the same masses of a solid substance in different forms such as lump, granules or powder, the smaller particle size of each form the larger the surface area.

Surface area increases from lumps to granules and them powder

Answer: it would stop producers from producing food.

Explanation: why? Without the action of the producers to turn sunlight into food, the producers would die, and consumers that rely on them would lose their food source and die too.

Answer:

It would stop producers from producing food

Explanation:

Producers would die, and if producers died, consumers would die too.

Hope this helps

Answer:

This description can be expressed as follows:

Y > W > XY>W>X

And,

W=ZW=Z

From these expressions we are able to find out that the saltiest cell description is Y, while the less salty is X.

Now, salt is well known as a dehydrating agent. In a process called osmosis cells placed in a salty liquid environment lose water, how?

Well, cells have a semipermeable membrane, in which some substances can get inside. Cells also have water inside. If a cell is placed in a quite salty liquid environment, salt will make the water inside the cells to come out, drying the cell and diminishing its size.

So, in this case, according to the expressions above, Cell Y will look the smallest, while cell X will look the biggest.

If we pour pure water in each liquid, the salt concentration will change and each cell will begin to grow bigger, but the saltiest cell will still be smaller than the others with less salt concentration.

Answer:

it is all of the above

Explanation:

Answer:

Carbon dioxide

Explanation:

Because CO2

Answer:

Element is made from same type of atoms

While atom is present in element made up of different particles like proton neutrons electron etc

Explanation:

Answer:

Decomposition

Explanation:

hope it helps you

Answer:

Sulphur

Explanation

Rhombic and monoclinic sulphur are its allotropic forms

Answer:

The moles of PH₃ produced are 0.2742 and the total number of moles of gas present at the end of the reaction is 0.6809.

Explanation:

Phosphorus reacts with H₂ according to the balanced equation:

P₄ (s) + 6 H₂ (g) ⇒ 4 PH₃ (g)

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of each compound participate in the reaction:

Being the molar mass of the compounds:

The following mass amounts of each compound participate in the reaction:

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P * V = n * R * T

In this case you know:

Replacing:

2 atm*10 L= n*0.082 [tex]\frac{atm*L}{mol*K}[/tex] *298 K

and solving you get:

[tex]n=\frac{2 atm*10 L}{0.082\frac{atm*L}{mol*K}*298 K }[/tex]

n=0.818 moles

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, you can use a simple rule of three as follows: if 6 moles of H₂ react with 124 g of P₄, 0.818 moles of H₂ with how much mass of P₄ will it react?

[tex]mass of P_{4}=\frac{0.818 moles of H_{2}*124 grams of P_{4}}{6 moles of H_{2}}[/tex]

mass of P₄= 16.90 grams

But 16.90 grams of P₄ are not available, 8.50 grams are available. Since you have less mass than you need to react with 0.818 moles of H₂, phosphorus P₄ will be the limiting reagent.

Then you can apply the following rules of three:

[tex]moles of PH_{3} =\frac{8.5 grams of P_{4}*4 moles of PH_{3} }{124grams of P_{4}}[/tex]

moles of PH₃=0.2742

[tex]moles of H_{2} =\frac{8.5 grams of P_{4}*6 moles of H_{2} }{124grams of P_{4}}[/tex]

moles of H₂= 0.4113

If you have 0.818 moles of H₂, the number of moles of gas H₂ present at the end of the reaction is calculated as:

0.818 - 0.4113= 0.4067

Then the total number of moles of gas present at the end of the reaction will be the sum of the moles of PH₃ gas and H₂ gas that did not react:

0.2742 + 0.4067= 0.6809

Finally, the moles of PH₃ produced are 0.2742 and the total number of moles of gas present at the end of the reaction is 0.6809.

The ideal gas equation gives the approximate amount of PH₃ produced

and the gas at the conclusion as 0.28 and 0.69 moles respectively.

Response:

First part:

Second part:

Given:

Mass of phosphorus = 8.50 g

Pressure of hydrogen gas, P = 2.00 atm

Volume of hydrogen gas, V = 10.0–L

Temperature of the gas, T = 298 K

First part:

From the ideal gas equation, P·V = n·R·T, we have;

[tex]Number \ of \ moles, \ n = \mathbf{\dfrac{P\cdot V}{R \cdot T}}[/tex]

Where for the hydrogen gas, H₂, we have;

P = 2.00 atm

V = 10.0 L

T = 298 K

The universal gas constant, R = 0.08205 L·atm·mol⁻¹·K⁻¹

Which gives;

[tex]n = \mathbf{ \dfrac{2.00 \times 10.0}{0.08205 \times 298}} \approx 0.82[/tex]

The number of moles of H₂ in the reaction, n ≈ 0.82 moles

Therefore;

1 mole of P₄(s) and 6 moles of H₂(g) produces 4 moles of PH₃(g)

Molar mass of P₄ ≈ 123.9 g

Which gives;

Number of moles in 8.50 g of phosphorus = [tex]\frac{8.5}{123.9}[/tex] ≈ 0.069

0.069 moles of P₄ will react with 0.069 × 6 moles ≈ 0.41 moles of H₂ to produce 0.069 × 4 moles ≈ 0.28 moles of PH₃

Second part:

The total number of moles of gas present at the conclusion of the reaction is therefore;

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2Ag⁺(aq) + Mg(s)→ 2Ag(s) + Mg²⁺ (aq)

Given

Standard cell notation:

Mg(s) | Mg2+ (aq) || Ag+(aq)| Ag(s)

Required

a balanced redox reaction

Solution

At the cathode the reduction reaction occurs, the anode oxidation reaction occurs

In reaction:  

Ag⁺ + Mg → Ag + Mg²⁺  

half-reactions

Ag⁺ (aq) + e⁻ ---> Ag (s)  x2

2Ag⁺ (aq) + 2e⁻ ---> 2Ag (s)

Mg (s) → Mg²⁺ (aq) + 2e−

a balanced cell reaction

2Ag⁺(aq) + Mg(s)→ 2Ag(s) + Mg²⁺ (aq)

Answer:2Ag⁺(aq) + Mg(s)→ 2Ag(s) + Mg²⁺ (aq)

Explanation:

just took test

Answer:

Your answer is C

Explanation:

The option that best describes a galvanic cell is that a battery containing a spontaneous redox reaction. That is option C.

A Galvanic cell is simply defined as an electrochemical cell that uses the movement of electrons in a reduction-oxidation reaction to produce electrical energy for use.

A Galvanic cell is a battery and is made up of a conducting electrolyte solution and two halve cells which include:

In the galvanic cell a spontaneous redox reaction occurs which involves the transfer of electrons from anode to cathode with the release of energy.

Therefore, the option that best describes a galvanic cell is that it is a battery containing a spontaneous redox reaction.

Answer:

i just took it the answers is C

Explanation:

Answer:

False

Explanation:

Answer:

Hydrogen chloride (HCl) and Calcium hydroxide (CaOH). (see balanced equation below)

Explanation:

In a neutralization reaction as is the case of the question (see attachment), an acid would be neutralized by a base to form salt and water.

The most plausible reactants for the reaction given the number of moles of the product, is therefore Hydrogen chloride (HCl) and Calcium hydroxide (Ca(OH)2).

[tex]HCl _{(aq)} + Ca(OH)_{2} _{(aq)}[/tex] →[tex]CaCl_{2}_{(s)} + H_{2} O_{(l)}[/tex]

Let me know if this was helpful.