How do you do this question?

Answer:

Explanation:

Following Avogadro's principle, under ideal condtions, the volume of the gases at the same conditions of temperature, and pressure, is proportional to the number of molecules.

Then, you can calculate the number of molecules for each of the gases to determine which is the sample with the greatest number of molecules and, hence, which will have the greatest volume at STP (standard temperature and pressure).

The formula to calcualte the number of molecules (in moles) is:

Then, since the mass is the same (22 g) for the four options, the result will be dependent on the molar mass: the gass witht the smallest molar mass will give the largest number of moles for 22 g, and will have the  greatest volume.

a) 22 g CO:

b) 22 g He:

c) 22 g O₂

d) 22 g Cl₂

Conclusion: since He has the smallest molar mass, the sample of 22 g of He gas will have the greatest volume at STP.

All the given samples, i.e., CO, He, O2, and Cl2, each having a mass of 22 grams would occupy the same volume at standard temperature and pressure (STP) due to Avogadro's Law. Each of these samples is equivalent to 0.5 moles and thus, would occupy the same volume.

The volume of a gas at standard temperature and pressure (STP) is determined by the number of moles of the gas, not its mass. This is based on Avogadro's Law which states that equal volumes of all gases, at the same temperature and pressure, have the same number of molecules.

All of these samples are equivalent to 0.5 moles (given that the molar masses of CO, He, O2, and Cl2 are 28, 4, 32, and 71 g/mol respectively). Therefore, at STP (which is defined as a temperature of 273 K and a pressure of 1 atmosphere), each of these gas samples would occupy the same volume - about 11.2 liters (as a mole of any gas at STP occupies 22.4 liters).

So, the correct answer is that all these samples would have the same volume at STP.

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Answer  they are all true.

Explanation:

The Unabomber had no identity until he finally confessed in 1998. Therefore, the answer is true, (its almost like a trick question.)

The Polygraph machine does measure physical changes in the body, so the answer is true.

False positives are when the examinee tells a truth but it is recorded as a lie.

hydrogen ions

H2SO4

HNO3

H3PO4

etc

Answer:

Explanation:

1) Data:

a) V = 75.0 liter

b) n = 15.82 mol

c) p = 546.8 kPa

d) T = ?

2) Formula:

Where:

3) Solution:

a) Solve the equation for T:

b) Substitute and compute:

(since the volume is expressed with 3 significant figures, the answer must show also 3 significant figures)

Summer because the seasons in the Southern Hemisphere is the opposite of the seasons in the northern hemisphere.

Answer:

True

Explanation:

as the ph of pure water is 7

(-)log(10^-7) = 7

The statement if the pH of pure water is 7.0, the hydroxide ion concentration in pure water is 1 × 10⁻⁷M is true.

Hydroxide ion concentration in the solution will be calculated by using the below equation as:

pOH = -log[OH⁻]

Relation between pH and pOH is :

pH + pOH = 14

Given that, pH = 7

So, pOH = 14 - 7 = 7

By using first equation, we have

7 = -log[OH⁻]

[OH⁻] = 10⁻⁷M

Hence, hydroxide ion concentration in pure water is 1×10⁻⁷M.

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Answer:

4.31 atm.

Explanation:

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R  is the general gas constant,

T is the temperature of the gas in K.

(P₁T₂) = (P₂T₁)

P₁ = 3.81 atm, T₁ = 25°C + 273 = 298 K,

P₂ = ??? atm, T₂ = 50°C + 273 = 323 K,

(P₁T₂) = (P₂T₁)

∴ P₂ = (P₁T₂)/(T₁) = (3.81 atm)(323 K)/(298 K) = 4.31 atm.

Answer:

Rb, Na, Al, N, F

Explanation:

Rb has an EN of 0.8, Na with 0.9 EN, Al with 1.5 EN, N with 3.0 EN, and F with 4.0 EN.

The elements Rb, F, Al, N, and Na are arranged in order of increasing electronegativity as Rb < Na < Al < N < F. Fluorine is the most electronegative while Rubidium is the least.

Electronegativity is a measure of the ability of an atom to attract electrons. In general, electronegativity increases from left to right across a period and decreases down a group in the periodic table. Based on this trend, the elements Rb, F, Al, N, and Na can be arranged in order of increasing electronegativity as follows: Rb < Na < Al < N < F. It's important to note that Fluorine (F) is the most electronegative element on the periodic table, followed by Nitrogen (N). Al (Aluminum), Na (Sodium), and Rb (Rubidium) are less electronegative as you go from right to left and down the periodic table.

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The elements Rb, F, Al, N, and Na are arranged in order of increasing electronegativity as Rb < Na < Al < N < F. Fluorine is the most electronegative while Rubidium is the least.

Electronegativity is a measure of the ability of an atom to attract electrons. In general, electronegativity increases from left to right across a period and decreases down a group in the periodic table. Based on this trend, the elements Rb, F, Al, N, and Na can be arranged in order of increasing electronegativity as follows: Rb < Na < Al < N < F. It's important to note that Fluorine (F) is the most electronegative element on the periodic table, followed by Nitrogen (N). Al (Aluminum), Na (Sodium), and Rb (Rubidium) are less electronegative as you go from right to left and down the periodic table.

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Answer:

Sound needs a medium through which to travel.

Explanation:

In space there is no air or medium. Sound waves  need medium to travel. It cannot travel through vacuum. Sounds waves are mechanical waves unlike electromagnetic waves. Electromagnetic waves can travel through vacuum. But mechanical waves such as sound waves needs a medium to propagate the energy. So it is very unlikely that people inside the space station can hear the explosion that occurs in space outside the space station.

Answer:

To control what substances enter and leave the cell

Explanation:

The cell membrane controls the movement of substances in and out of cells and organelles. In this way, it is selectively permeable to ions and organic molecules.

Answer:

To control what substances enter and leave the cell

Explanation:

Answer:

[tex]\boxed{x = 10}[/tex]

Explanation:

This is like an empirical formula question, except that you are finding the molar ratio of compounds instead of atoms.

Step 1. Gather the information in one place.

M_r:                                            142             18

           Na₂SO₄·xH₂O(s) ⟶ Na₂SO₄(s) + xH₂O(g)

m/g:              3.22                      1.42

Step 2. Calculate the mass of the water

Mass of H₂O = mass of Na₂SO₄·xH₂O – mass of Na₂SO₄

= 3.22 – 1.42 = 1.80 g

Step 3. Calculate the moles of each product

Na₂SO₄: [tex]n = \text{1.42 g} \times \dfrac{\text{1 mol}}{\text{142 g}} = \text{0.0100 mol}[/tex]

     H₂O: [tex]n = \text{1.80 g} \times \dfrac{\text{1 mol}}{\text{18 g}} = \text{0.100 mol}[/tex]

Step 4. Calculate the molar ratios

[tex]\dfrac{\text{moles of Na$_{2}$SO$_{4}$}}{\text{moles of H$_{2}$O}} = \dfrac{0.0100}{0.100} = \dfrac{1}{10}[/tex]

[tex]\boxed{x = 10}[/tex] , so the formula of the compound is Na₂SO₄·10H₂O

Answer:

D. 0.60 L.

Explanation:

The no. of millimoles of acid is equal to that of the base at the neutralization.

∴ (XMV) NaOH = (XMV) H₂SO₄.

X is the no. of reproducible H⁺ (for acid) or OH⁻ (for base),

M is the molarity.

V is the volume.

X = 1, M = 4.0 M, V = ??? L.

X = 2, M = 4.0 M, V = 0.3 L.

∴ V of NaOH = (XMV) H₂SO₄/(XM) NaOH = (2)(4.0 M)(0.3 L)/(1)(4.0 M) = 0.6 L.

So, the right choice is: D. 0.60 L.

Answer: The correct answer to this problem is 2.

Explanation:

We are given a mathematical problem, which is:

1 + 1 = ?

To solve this, we use the mathematical operator known as addition. In this, we add two numbers and the resulting value is the answer to the problem.

By adding 1 and 1, we get:

[tex]\Rightarrow 1+1=2[/tex]

Thus, the correct answer to this problem is 2.

the hard shell off the egg

Answer: D

They are gases at room temperature

Hope this helps:)

The smallest alkanes, which are those with one to four carbon atoms, are gases at room temperature due to their nonpolar nature and weak dispersion forces.

The physical state of the smallest alkanes at room temperature can be understood by analyzing their properties and boiling points. Alkanes are nonpolar molecules associated through weak dispersion forces. The boiling point of a substance is a rough measure of the energy needed to separate molecules from each other. In the case of the smallest alkanes, specifically those with one to four carbon atoms, they are gases at room temperature. Example alkanes that are gases at room temperature include methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10). In contrast, the physical state changes as the number of carbons increases; alkanes become liquids and eventually solids as the carbon chain length and molecular weight increase.

The law is Boyel's law.

One of the primary laws of material science that impacts the submerged jumping condition for scuba jumpers is Boyle's law.  

The law states that as weight changes, the volume of gases in a jumper's body pits and adaptable gear changes as well. Where the water weight builds, 'air spaces' reduces in size, yet as water weight diminishes, the 'air spaces' increments in size. Where the two changes are in direct extent to the weight increment or lessening, the temperature is held consistent.  

The answer is d ionic

Answer:

Explanation:

The formula equations given are:

        [there is also a Pt symbol over the arrow, which means that Pt

          is a catalyst]

Reversible reactions are reactions that may happen in both directions, i.e. there is a direct or forward reaction and a reverse reaction.

The symbol used to show a reversible reaction is the double arrow (⇄).

The double arrow shows tha both left side substances and right side substances are reactants and products.

In the reaction NH₄CI(s) ⇄ NH₃(g) + HCI(g) you have:

All the other equations are written with a single arrow, so they are not reversible reactions.

Answer:

just did edge test, got 100%:

C. NH4Cl(s)<-->NH3(g) + HCl(g)

Answer:

Explanation:

The reaction given follows this pattern:

1) Decomposition reaction:

2) First-order kinetic with respect to MN and first-order overall:

                       [tex]ln\frac{[MN]}{[MN]_0}=-kt[/tex]

                               t = τ

 ∴ τ =  ln(2) / k ⇒ k = ln (2) / τ =  ln(2) / 2.3 × 10⁴ s / ln(2) = 3.0 × 10⁻⁵ s⁻¹

The rate constant for a first-order reaction can be calculated using the half-life of the reaction. In this case, the rate constant for the given reaction at 25°C is 3.0 × 10⁻⁵ s⁻¹.So,option c is correct.

The rate law for a first-order reaction is given by: Rate = k[reactant]

The half-life of a first-order reaction can be calculated using the formula: t1/2 = 0.693 / k

Given that the half-life of the reaction is 2.3 × 10⁴s and it is first order overall, the rate constant can be calculated as k = 0.693 /[tex]t_{ 1/2}[/tex] = 0.693 / 2.3 × 10⁴ = 3.0 × 10⁻⁵ s⁻¹.

Answer:

Explanation:

A chemical element is a pure substance formed by atoms with the same atomic number (number of protons). This is because it is the number of protons what identifies an element.

For example: oxygen is a chemical element, so oxygen is formed by only atoms of oxygen, and the atomic number of those atoms is 8, because every oxygen atom has 8 protons.

Nevertheless, some atoms of oxygen, may have different number of neutrons. Isotopes are different kind of atoms of the same element, which only differ in the number of neutrons. So, some atoms of oxygen will have 8 neutrons, other 9 neutrons, and other 10 neutrons (those are the stable isotopes of oxygen).

That difference in neutrons, is generally accepted that, does not modifiy substantially the chemical properties of the element, but the mass number. So, the isotopes with more neutrons wil be heavier, and the isotopes with less neutrons will be lighter.

In general a chemical element is formed by a mixutre of isotopes of the same element.

Answer:

its B :diffrent number of neutrons

Explanation:

Temperature is a measurement of heat whereas heat is just an energy.

With that being said the heat is moving from hot to cold.

Answer:

Explanation:

So let's define both of these . these are two different things

Temperature : it's average kinetic energy of the particles within the system .

So if I increase the motion of particles ,the temperature will increase . If I decrease the motion of particles ,the temperature will decrease

Heat : it is the flow of energy due to temperature difference .

If I have a metal strip and I heat one side of it and the other side is cold then due to temperature difference ,heat will flow from the heated part of the metal strip to cold part of the strip.

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

Heat only provides a direction of the flow of heat while temperature is just the average kinetic energy of the substance ( it has no direction .BUT here are some more differences :

Heat is measured by a device called caloriometer

Temperature is measured by Thermometer

Unit of heat : joules

Unit if temperature : Kelvin

Answer: The rock formed from cooling lava.

Explanation:Extrusive igneous rocks, also known as volcanic rocks, are formed at the crust's surface as a result of the partial melting of rocks within the mantle and crust.

A geologist concludes that a rock sample is an extrusive igneous rock.The rock formed from cooling lava is accurate.

A geologist concludes that a rock sample is an extrusive igneous rock.The rock formed from cooling lava is accurate.

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Hello!

Your answer is “e”

Electronegativity of an atom is it's ability to attract electrons during bond formation.

Answer: Option (E) is the correct answer.

Explanation:

Electronegativity is defined as the ability of an atom to attract electrons towards itself while formation of bond.

For example, chlorine is electronegative in nature and hence it will readily combine with potassium atom as potassium has one extra electron in its valence shell.

                        [tex]K + Cl \rightarrow KCl[/tex]

Thus, we can conclude that electronegativity of an atom is its ability to attract electrons during bond formation.

Answer:

The weak nuclear force.

Explanation:

This force is active in radioactivity.

Answer:

The new volume of the balloon is 600cm³

Explanation:

Given parameters:

Initial Volume, which is V₁ = 200cm³

Initial temperature, T₁ = 60°C

Final temperature T₂ = 180°C

Final Volume V₂ =?

To solve this kind of problem, we apply one of the gas laws that shows the relationship between volume and temperature.

This law is the Charles law, it states that " the volume of a fixed mass of a gas is directly proportional to its absolute temperature if pressure is constant".

It is simply expressed as:

V₁/T₁ = V₂/T₂

Since our unknown is V₂, we make it the subject of the expression given above:

V₂ = V₁T₂/T₁

Now input the corresponding values and solve:

V₂ = 200 x 180 / 60

V₂ = 36000/60

V₂ = 600cm³

The new volume of the balloon is 600cm³

Answer:

92.4 grams.

Explanation:

CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O,

1.0 mole of CaCO₃ reacts with 2.0 moles of HCl to produce 1.0 mole of CaCl₂, 1.0 mole of CO₂, and 1.0 mole of H₂O.

no. of moles of CaCO₃ = mass/molar mass = (104 g)/(100.08 g/mol) = 1.039 mol.

Using cross multiplication:

1.0 mole of CaCO₃ produce → 1.0 mole of CaCl₂.

∴ 1.039 mole of CaCO₃ produce → 1.039 mole of CaCl₂.

∴ The amount of CaCl₂ produced = no. of moles x molar mass = (1.039 mol)(110.98 g/mol) = 114.3 g.

∵ percent yield of the reaction = [(actual yield)/(theoretical yield)] x 100.

Percent yield of the reaction = 80.15%, theoretical yield = 115.3 g.

∴ actual yield = [(percent yield of the reaction)(theoretical yield)]/100 = [(80.15%)/(115.3 g)] / 100 = 92.42 g ≅ 92.4 g.

Answer:

The chemical equation needs to be balanced so that it follows the law of conservation of mass. A balanced chemical equation occurs when the number of the different atoms of elements in the reactants side is equal to that of the products side. Balancing chemical equations is a process of trial and error.

Explanation:

Final answer:

To find the number of grams in 2.3 x 10-4 moles of calcium phosphate (Ca3(PO4)2), you need to calculate the molar mass of calcium phosphate and then convert moles to grams.

Explanation:

To find the number of grams in 2.3 x 10-4 moles of calcium phosphate (Ca3(PO4)2), we need to calculate the molar mass of calcium phosphate and then convert moles to grams.

The molar mass of Ca3(PO4)2 can be calculated by adding the atomic masses of calcium (Ca), phosphorus (P), and oxygen (O). The atomic masses are: Ca = 40.078 g/mol, P = 30.973761 g/mol, O = 15.9994 g/mol.

Calculating the molar mass:

Total molar mass of Ca3(PO4)2 = 120.234 g/mol + 61.947522 g/mol + 127.9952 g/mol = 310.176722 g/mol.

Now, we can use the equation:

mass(g) = moles x molar mass(g/mol)

Substituting the given values:

mass(g) = 2.3 x 10-4 moles x 310.176722 g/mol

Calculating the result:

mass(g) = 0.0712 g

Therefore, there are 0.0712 grams in 2.3 x 10-4 moles of calcium phosphate (Ca3(PO4)2).

Answer : The correct option is, Add coefficient 2 to [tex]O_2[/tex] on the left side of the equation.

Explanation :

Balanced chemical reaction : It is defined as the reaction in which the number of atoms of individual elements present on reactant side must be equal to the product side.

The reactants and the products are separated by right arrow.

The species present on the left side of the right arrow is known as reactant and the species present on the right side of the right arrow is known as product.

If the amount of atoms of each type on the left and right sides of a reaction differs then to balance the equation by adding coefficient in the front of the elements or molecule or compound in the chemical equation.

The coefficient tell us about that how many molecules or atoms present in the chemical equation.

The given chemical reaction is,

[tex]CH_4+O_2\rightarrow CO_2+2H_2O[/tex]

This reaction is an unbalanced chemical reaction because in this reaction number of oxygen atoms are not balanced.

In order to balance the chemical equation, the coefficient '2' put before the [tex]O_2[/tex] and we get the balanced chemical equation.

The balanced chemical reaction will be,

[tex]CH_4+2O_2\rightarrow CO_2+2H_2O[/tex]

Hence, the correct option is, Add coefficient 2 to [tex]O_2[/tex] on the left side of the equation.

These are five questions and five answers.

1) Question 1. A sample of pure calcium fluoride with a mass of 15.0 g contains 7.70 g of calcium. How much calcium is contained in 40.0 g of calcium fluoride?

Answer:

Explanation:

Calcium fluoride being a pure substance, has a fixed chemical compositon, which means that their elements (atoms), in any sample, are always in the same proportion.

Then, you can set the followoing proportion:

Now, solve for x:

The answer must be expressed with 3 significan figures, since the three data are given with 3 significan figures.

2) Question 2. Silver has two isotopes. One isotope contains 60 neutrons and has a percent abundance of 51.839% the other contains 62 neutrons. Give the atomic symbols for the two isotopes.

Answer:

Explanation:

         Isotope that contains 60 neutrons: A = 60 + 47 = 107

         Isotope that contains 62 neutrons: A = 62 + 47 = 109

         Isotope with 60 neutrons: ¹⁰⁷₄₇Ag

         Isotope with 62 neutrons:  ¹⁰⁹₄₇Ag

3) Question 3. What is the average atomic weight of silver? What is the mass (in grams) of a single chlorine molecule?

Answer:

Explanation:

The atomic wieght of the elements is the weighted average weight of the different isotopes of the same element found in the nature,  taking into account their relative abundance.

Average atomic weight = ∑( abundance × individual atomic weight)

4) Question without number: What is the mass (in grams) of a single chlorine molecule

Answer:

Explanation:

The chlorine molecule is diatomic. That means that each molecule contains two atoms. The chemical formula of chlorine molecule is Cl₂.

The mass of one mole of molecules of Cl₂ is 2 × 35.453 g/mol = 70.906 g/mol

5) Question 4. How many moles of ethanol (CH₃CH₂OH) are in 141 mg?

Answer:

Explanation:

In 40.0 g of calcium fluoride, there is 20.53 g of calcium. Silver has two isotopes represented by Ag-107 and Ag-109, with the average atomic weight of silver calculated by using their percent abundances. For ethanol, 141 mg corresponds to 0.00306 moles.

Calcium is contained in 40.0 g of calcium fluoride (CaF₂), we use a proportional relationship based on the information provided:

15.0 g of CaF₂ contains 7.70 g of calcium.

40.0 g of CaF₂ contains X g of calcium.

By setting up a proportion, we solve for X:

(7.70 g Ca / 15.0 g CaF₂) = (X g Ca / 40.0 g CaF₂)X = (7.70 g Ca / 15.0 g CaF₂)
40.0 g CaF₂)

X = 20.53 g of calcium.

The atomic symbols for the two isotopes of silver are: Ag-107 (47 protons + 60 neutrons) and Ag-109 (47 protons + 62 neutrons).

The average atomic weight of silver is calculated considering the weighted average of these isotopes and their percent abundances. The mass of a single chlorine molecule (Cl₂), not a chlorine atom, would be the sum of the atomic masses of the two chlorine atoms. However, the specific mass for a single molecule of Cl₂ in grams is a very small number, given that it's typically calculated in atomic mass units.

Finding the number of moles of ethanol (CH₃CH₂OH) in 141 mg:

The molar mass of ethanol is approximately 46.07 g/mol. Therefore:(141 mg) (Unit conversion from mg to g: 141 mg * (1 g/ 1000 mg)) (Divide by the molar mass of ethanol: (0.141 g) / 46.07 g/mol) = 0.00306 mol of ethanol.