A block of lead weighs 11.3 grams. How many atoms of lead are in this sample?
• Use 6.022 x 1023 mol
for Avogadro's number.​

Answer:

because they can create noise

Explanation:

sounds is through music or songs but vibration is just quick vibrate music, not quite sure , it's just my instinct, lol

Answer:

a. 0.183 mol C

b. 0.366 mol H

Explanation:

Assuming total combustion, all of the carbon in the unknown compound turned into carbon dioxide, CO₂.

So first we calculate the CO₂ moles produced, using its molecular weight:

This means in the unknown compound there were 0.183 moles of carbon, C.

Conversely, all of the hydrogen in the unknown compound turned into water, H₂O.

Calculating the H₂O moles:

We multiply the water moles by two, as there are 2 H moles per H₂O mol:

Answer: the last one

Explanation: if a cell has too little water, it will begin to function incorrectly, and if a cell has too much water it will burst.

Answer:

Fe^2+(aq) = 4.51 × 10^-11 M

Fe3+(aq) = 1.79 × 10^5 M.

Explanation:

So, the first thing to do is to to write out the chemical reaction showing the ionic reaction of the chemical species present in the chemical reaction;

4Fe^2+ (aq) + O2(g) + 4H^+ <---------------------------> 4Fe^3+(aq) + 2H2O(l).

The next thing to do is to determine or calculate for G° and the equilibrium constant,kc. Thus, the value of G° = 4(-4.6) + 2(-237.18) - {4(-78.87)} = -177.28 kJ/mol.

Therefore, the equilibrium constant = e^-∆G°/RT = 1.19 × 10^31.

Therefore the value for Fe^2+ and Fe^3+ can be determine as;

NB=> Recall that [Fe^3+]/[Fe^2+] = kc [(Po2) (H^+)^4]^1/4.

Also, 1/ 55850 = 1.79 × 10^-5 M.

[Fe^2+] + [Fe^3+] = 1.79 × 10^-5. -------(1).

Therefore, [Fe^3+]/[Fe^2+] = kc [(Po2) (H^+)^4]^1/4. = [Fe^3+]/[Fe^2+] = [ 1.19 × 10^31 × 0.2095 × (10^2)^2] ^1/4 = 3.97 × 10^5.

Therefore, [Fe^3+]/[Fe^2+] = 3.97 × 10^5.

[Fe^3+] = 3.97 × 10^5[Fe^2+].

Hence, using the equation (1) above we can determine the value of the species.

[Fe^2+] + [Fe^3+] = 1.79 × 10^-5

[Fe^2+] + [Fe^2+] = 1.79 × 10^-5.

[Fe^2+] + 3.97 × 10^5[Fe^2+] = 1.79 × 10^-5.

[Fe^2+] = 4.51 × 10^-11 M.

Therefore, we will have [Fe^3+]/[Fe^2+] = 3.97 × 10^5.

Thus, [Fe^3+] = [Fe^2+] × 3.97 × 10^5. = 1.79 × 10^5 M.

The question is incomplete, the complete question is;

Compare Homogeneous and Heterogeneous Equilibria Question Which type of equilibrium is more likely to omit substances from the equilibrium constant expression? Select the correct answer below: O homogeneous equilibria O heterogeneous equilibria O a and b are equally likely O there is no correlation

Answer:

heterogeneous equilibria

Explanation:

In a heterogeneous equilibria, there are species of different phases present in the equilibrium expression. Some of these heterogeneous substances may be pure solids.

Remember that the solids and pure liquids are eliminated from the final equilibrium expression.

Thus, when writing equilibria involving heterogeneous substances, solids and pure liquids do not appear in the final equilibrium expressions.

Answer:

CaSO₄ (calcium suflate) is the precipitate formed

Explanation:

We can think the reactants:

BeSO₄ → Beryllium sulfate

Ca(OH)₂ → Calcium hydroxide

The reaction is:

Be₂SO₄  +  Ca(OH)₂  →  CaSO₄ ↓  +  Be(OH)₂

We call it as a double-replacement reaction because two ions exchange places from 2 compounds to form two new compounds.

Sulfates can always make precipitate with the elements from group 2, Ca, Ba and Mg.  

Hydroxides from group 2 are solubles, so we complete states:

BeSO₄ (aq)  +  Ca(OH)₂ (aq)  →  CaSO₄ ↓ (s)  +  Be(OH)₂ (aq)

Answer:

27

Explanation: volume-3 times 6=18 /mass- 81 times 6= 486....  486 divided by 18 = 27.... a cube has 6 sides.

The density of a substance is simply defined as the mass of the subtance per unit volume of the substance.

[tex]Density = \frac{Mass }{Volume }[/tex]

To obtain the density of the aluminum, we'll begin by calculating the volume of the aluminum. This can be obtained as follow:

From the question given above, each side of the aluminum cube measures 3 cm. Thus,

Length (L) = 3 cm

Width (W) = 3 cm

Height (H) = 3 cm

Volume = Length × Width × Height

Volume = 3 × 3 × 3

Therefore, the volume of the aluminum is 27 cm³

Finally, we shall determine the density of the aluminum. This can be obtained as follow:

Mass = 81 g

Volume = 27 cm³

[tex]Density = \frac{Mass }{Volume }\\\\Density = \frac{81}{27}[/tex]

Therefore, the density of the aluminum is 3 g/cm³

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Answer:

0.41g/L

Explanation:

To find the concentration of the albumin in the mixture we need to find the mass in grams and the volume in liters of the solution:

Mass of albumin:

0.20x10⁻³L * (6.0g / L) = 1.2x10⁻³g of albumin

Volume of the solution:

0.20mL + 2.72mL = 2.92mL = 2.92x10⁻³L

Thus, concentration of albumin is:

1.2x10⁻³g of albumin / 2.92x10⁻³L =

Answer:

2Cr³⁺(aq) + 3S²⁻(aq) ----> Cr₂S₃(s)

Explanation:

When aqueous solutions of chromium(III) chloride and ammonium sulfide are  mixed together, chromium (III) chloride and ammonium sulfide undergoes a double displacement reaction to produce chromium (iii) sulphide as a precipitate and ammonium chloride which remains in solution.

The general equation of the reaction is given below:

2CrCl₃(aq) + 3(NH₄)₂S(aq) ----> Cr₂S₃(s) + 6NH₄Cl(aq)

The net equation of the reaction is given below:

2Cr³⁺(aq) + 3S²⁻(aq) ----> Cr₂S₃(s)

Answer:

s = 22.352 m/s

Explanation:

Given data:

Time taken = 0.5 hours

Distance cover = 25 miles

Car speed = ?

Solution:

First of all we will convert the units.

1 hour = 3600 sec

0.5 hr ×3600 sec / 1hr = 1800 sec

miles to meter:

25 mi × 1609 m/ 1 mi = 40233.6 m

Formula:

s =  d/t

s = speed

d = distance

t = time

Now we will put the values in formula.

s = 40233.6 m / 1800 sec

s = 22.352 m/s

Answer:

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the iodide ion will be __6__.

Explanation:

From the redox equation, we can see that NO₃⁻ is reduced to NO (from oxidation state +5 to +2), whereas I⁻ is oxidized to I₂ (from oxidation state -1 to 0). The half reactions are balanced with H⁺ (acidic solution), as follows:

Reduction :        2 x (NO₃⁻(aq) + 3 e-  + 4 H⁺ → NO(g) + 2 H₂O)

Oxidation :                                   3 x (2 I⁻(aq) → I₂(s) + 2 e-)

                       ----------------------------------------------------------------------

Total equation: 6 I⁻(aq) + 2 NO₃⁻(aq)+ 8 H⁺ → 3 I₂(s) + 2 NO(g) + 4 H₂O

That is the redox equation with the smallest whole number coefficients.

Accordin to this, the coefficient for the iodide ion (I⁻) is: 6.

The given redox equation is balanced with the smallest whole-number coefficients, the coefficient for the iodide ion will be 6.

Redox reaction is the reaction in which oxidation and reduction both occur simultaneously.

From the redox equation, we can see that NO₃⁻ is reduced to NO (from oxidation state +5 to +2), whereas I⁻ is oxidized to I₂ (from oxidation state -1 to 0).

The half reactions are balanced with H⁺ (acidic solution), as follows: Reduction : 2 x (NO₃⁻(aq) + 3 e- + 4 H⁺ → NO(g) + 2 H₂O)

Oxidation : 3 x (2 I⁻(aq) → I₂(s) + 2 e-) ----------------------------------------------------------------------Total equation: 6 I⁻(aq) + 2 NO₃⁻(aq)+ 8 H⁺ → 3 I₂(s) + 2 NO(g) + 4 H₂O

That is the redox equation with the smallest whole number coefficients.

According to this, the coefficient for the iodide ion (I⁻) is: 6.

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Answer: Wax

Explanation:

Density is defined as the mass contained per unit volume.

[tex]Density=\frac{mass}{Volume}[/tex]

Usually solids are more denser than liquid, as molecules in solid are more strongly packed and thus have more mass per unit volume.

Liquids on the other hand contain molecules which are less tightly bound and thus thus contain less mass per unit volume as compared to solid.

Example: Solid wax is more denser than liquid wax.

Answer: The size actually does not matter. But planets with smaller mass will have less gravity decreasing their weight. Other for larger mass planets, more mass is more gravity which is also more weight.

Explanation:

Explanation:

no of moles = no of atoms ÷ avogadro's number

= (9.8×10^24) ÷ (6.02×10^23)

Answer:

ZnCl2

sodium iodide

ammonium carbonate

Pb(NO3)2

Explanation:

Substances that dissolve in water can be accurately determined using the solubility rules.

According to the solubility rules, all nitrates are soluble. This implies that lead II nitrate is also soluble in water.

Similarly, all chlorides are soluble in water hence ZnCl2 is soluble in water.

Sulphates are soluble except those of Pb, Ba, Ca and Mg.

Also, NaI is highly soluble in water.

Lastly, all carbonate salts are insoluble except those of sodium, potassium and ammonium. Hence ammonium carbonate is soluble in water.

Answer:

1.68% is ionized

Explanation:

The Ka of benzoic acid, C₇H₆O₂, is 6.46x10⁻⁵, the equilibrium in water of this acid is:

C₇H₆O₂(aq) + H₂O(l) ⇄ C₇H₅O₂⁻(aq) + H₃O⁺(aq)

Ka = 6.46x10⁻⁵ = [C₇H₅O₂⁻] [H₃O⁺] / [C₇H₆O₂]

Where [] are concentrations in equilibrium

In equilibrium, some 0.225M of the acid will react producing both C₇H₅O₂⁻ and H₃O⁺, the equilibrium concentrations are:

[C₇H₆O₂] = 0.225-X

[C₇H₅O₂⁻] = X

[H₃O⁺] = X

Replacing:

6.46x10⁻⁵ = [X] [X] / [0.225-X]

1.4535x10⁻⁵ - 6.46x10⁻⁵X = X²

1.4535x10⁻⁵ - 6.46x10⁻⁵X - X² = 0

Solving for X:

X = -0.0038. False solution, there is no negative concentrations.

X = 0.00378M. Right solution.

That means percent ionization (100 times Amount of benzoic acid ionized  over the initial concentration of the acid) is:

0.00378M / 0.225M * 100 =

Answer:

c atomic numbers

Explanation:

hope this helps

Answer:

atomic numbers

Explanation:

In order for two atoms to be different, they have to have a different number of protons. Protons are represented by the atomic number. Thus, atoms of two DIFFERENT elements must have different atomic numbers.

I took the test and got 100%

Hope this helps!

Answer:

Mark as brainleist answer and thanks this answer

Answer:

see explanation

Explanation:

When caffeine is purified, the impurities are removed,  these impurities are responsible for the greater mass of pure caffeine compared to the mass of the pure sample.

The percent recovery of caffeine is frequently low because some caffeine is often left behind in the solvent during the process of recrystallization.

Secondly, since caffeine is a sublime substance, some caffeine may be lost o sublimation leading to a low percent recovery of pure caffeine.

Answer:

left to right across a period when it decreases and when it increases top to bottom in a group,

hope i helped

Answer:

Thus, at convergent boundaries, continental crust is created and oceanic crust is destroyed. Two plates sliding past each other forms a transform plate boundary. Natural or human-made structures that cross a transform boundary are offset—split into pieces and carried in opposite directions.

Explanation:

Answer:

C) F

Explanation:

Valence electrons are the electrons present in the outermost shell of an atom and have the highest energy level of an atom whereas electrons at ground state or lower orbitals have less potential energy.

This is so because orbitals nearby nucleus are strongly bonded with the atomic nucleus and have less energy than an outermost shell.

So, the potential energy states of an atom depend on the number of orbitals. In the given options fluorine with atomic number 9 has less number of orbitals that is 2 orbitals and valence electrons will be present in second orbitals, so fluorine will have the lowest average potential energy states.

Hence, the correct option is "C) F".

Answer:

C renewable

Explanation:

because renewable energy repleneshes itself, therefore the quickest

Renewable resources are replenished MORE quickly than they are used (option C).

In conclusion, renewable resources are replenished MORE quickly than they are used (option C).

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Answer:

See explanation

Explanation:

When the temperature was increased, the pressure of the gas in the can was increased.

When Maria removed the can and placed it in cold liquid, the decrease in temperature led to a corresponding decrease in pressure of the gas inside the can hence the can was crushed.

Hypothesis: The pressure of the gas in the can is directly proportional to temperature.

Maria was careless about the experiment. She ought to have first checked whether the hot plate was off before placing the soda can. Secondly,she should not have immediately plunged the soda can into liquid because it will shrink due to decrease in pressure. She should not also have removed the soda can with bare hands to avoid getting burns and blisters.

Answer:

Strong electrolytes-2,4

Weak electrolyte-1,5

Non electrolyte- 3,6

Explanation:

The statements were labeled according to whether they define strong electrolytes, weak electrolytes or non electrolytes.

Strong electrolytes are completely dissociated in solution and form highly ionic solutions.

Weak electrolytes have medium conductivity and do not completely dissociate in solution.

Non electrolytes do not dissociate in solution and their solution does not conduct electricity.

1. Weak electrolyte solution: it contains a partially dissociated solute.

2. Strong electrolyte solution: it has the highest conductivity.

3. Non-electrolyte solution: it contains a complete solute.

4. Strong electrolyte solution: it contains a completely dissociated solute.

5. Weak electrolyte solution: it has a medium level of conductivity.

6. Non-electrolyte solution: it has little or no conductivity.

A solution can be defined as a homogenous mixture that contains two or more substances.

In Chemistry, there are three (3) main types of solution and these include:

1. Weak electrolyte solution: this is a type of solution in which only a small amount of dissolved solute exists as ions because it partially dissociates into its constituent anions and cations.

2. Strong electrolyte solution: this is a type of solution that contains only ions but no molecules of the electrolyte because it completely dissociates or ionizes in a solution.

3. Non-electrolyte solution: this is a type of solution that do not dissociates or ionizes in a solution.

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Answer: A) A theory is the best possible explanation based on all existing evidence

A law in physics and chemistry is a description of what is going on. For instance, newton's law of motion helps us find out an objects acceleration if we know its mass and the force applied. The theory of gravity on the other hand is the best guess we make as to why objects with mass are attracted to one another.

Theories change over time if new evidence is found that contradicts the old theory. Saying "a theory is more important than a law" is subjective, and I would argue that both are equally important in their own way.

The atomic theory a theory is the best possible explanation based on all existing evidence. The correct option is A.

The word theory renowned as to an untested hunch or one can say a guess with not having a supporting evidence.

A theory, has nearly the opposite implications for scientists. A theory is a well-supported explanation of an innate phenomenon that can encompass laws, hypotheses, along with facts.

Theories are developed to elaborate, predict, as well as comprehend phenomena, also to challenge and extend existing understanding within the constraints of critical boundary assumptions.

A theory does not become a scientific law as new or better evidence accumulates.

The theories are explanations, as well as laws are patterns located in large amounts of data that are frequently expressed as an equation. A theory will always be a theory in all aspect, and a law will always be a law.

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Answer:

From these two values, i.e. mass and volume, density of the copper cylinder can be calculated.

Formula of density is :

Density = Mass / volume.

Now we have mass: 53.76g and volume 6cm³

Density = 53.76 / 6

Density= 8.96 g/cm³

Answer:

43.75 ml

Explanation:

Given that the equation of the reaction is;

2HNO3(aq) + Ca(OH)2(aq) ---> Ca(NO3)2(aq) + 2 H20(l)

Concentration of acid CA= 0.05 M

Concentration of base CB = 0.02 M

Volume of acid VA = 35.00ml

Volume of base VB= ???

Number of moles of acid NA= 2

Number of moles of base NB=1

From

CAVA/CBVB= NA/NB

Making VB the subject of the formula;

VB= CAVANB/CBNA

VB= 0.05 × 35 × 1/ 0.02 × 2

VB=1.75 /0.04

VB= 43.75 ml