Select the correct answer.
An object's density equals its mass divided by its volume. If a certain object has a mass of 125.0 grams and a volume of 25 ml, what is its density
expressed to the correct number of significant figures?
OA 5.000 g/mL
OB. 5.0 g/ml
OC. 5.00 g/ml
OD. 5 g/mL

Answer: what are the choices?!.

Explanation:

Answer:

See explanation and images attached

Explanation:

The first image shows the structure of hydrogen peroxide. It does not exist as resonance structures. The structure and properties of the molecule can wholly be explained on the basis of a single Lewis structure.

However, the structure of the bicarbonate ion in sodium bicarbonate can not be completely described by a single Lewis structure. Hence, two resonance structures are shown for the bicarbonate ion. In each case, Na^+ is the counter ion.

Answer:

No of protons is equal to the atomic number.

Answer:

atomic number

Explanation:

Answer:

it's B

Explanation:

Write the balanced equation: H2SO4 + 2KOH → K2SO4 +2H2O. So 2(moles KOH) = (moles H2SO4); 2(volume KOH)(concentration KOH) = (volume H2SO4)(concentration H2SO4); 2(40ml)(0.2M) = (30ml)(x); x = 0.53M

The concentration of  H₂SO₄ solution is equal to 0.133 M.

A neutralization reaction can be described as a chemical reaction in which an acid and base react together to form respective salt and water. When a strong acid such as HCl will react with a strong base such as NaOH the salt can be neither acidic nor basic.

When H₂SO₄ (a strong acid) reacts with KOH, the resulting salt will be  K₂SO₄ and water.

H₂SO₄    +  2KOH   → K₂SO₄  +  2H₂O

Given, the concentration of KOH solution = 0.2 M

The volume of the KOH solution = 40 ml = 0.040 ml

The number of moles of KOH, n = M × V = 0.2 × 0.04 = 0.008 mol

The volume of the H₂SO₄ = 30 ml = 0.03 L

The number of moles of H₂SO₄, n = 0.008/2 = 0.004 mol

The concentration of  H₂SO₄ solution = 0.004/0.03 = 0.133 M

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Answer:

Explanation:

Continental tropical air masses are extremely hot and dry. Arctic, Antarctic, and polar air masses are cold. The qualities of arctic air are developed over ice and snow-covered ground. Arctic air is deeply cold, colder than polar air masses.

Answer:

Glass 1

Explanation:

Molarity is measured in moles of substance per liter.

For the sake of calculations, let's say that each glass contains 1 mole of juice and 1 liter after it is divided between the glasses. If you add an equal amount of water to glass 1 ( another liter), you now have:

Glass 1 = 1 mole / 2 liters = 0.5 M

Glass 1 = 1 mole/ 1 liter = 1 M

So glass 1 will have a lower molarity

Answer: The millimoles of potassium iodide the chemist has added to the flask is 522 millimoles.

Explanation:

Given: Volume of KI = 370.0 mL (1 mL = 0.001 L) = 0.37 L

Molarity of KI solution = 1.41 mol/L

Now, moles of KI (potassium iodide) is calculated as follows.

[tex]Moles = Volume \times Molarity \\= 0.37 L \times 1.41 M\\= 0.5217 mol[/tex]

Convert moles into millimoles as follows.

1 mol = 1000 millimoles

0.5217 mol = [tex]0.5217 mol \times \frac{1000 millimoles}{1 mol} = 521.7 millimoles[/tex]

This can be rounded off to the value 522 millimoles.

Thus, we can conclude that the millimoles of potassium iodide the chemist has added to the flask is 522 millimoles.

Answer:

0.287 M

Ba(OH)₂ + 2 HClO₄ ⇒ Ba(ClO₄)₂ + 2 H₂O

1.62 M

Explanation:

Step 1: Calculate the concentration of Ba(OH)₂

We will use the following expression.

[Ba(OH)₂] = mass Ba(OH)₂/ molar mass Ba(OH)₂ × liters of solution

[Ba(OH)₂] = 2.29 g/ 171.34 g/mol × 0.0466 L = 0.287 M

Step 2: Write the balanced neutralization equation

Ba(OH)₂ + 2 HClO₄ ⇒ Ba(ClO₄)₂ + 2 H₂O

Step 3: Calculate the reacting moles of Ba(OH)₂

25.5 mL of 0.287 M Ba(OH)₂ react.

0.0255 L × 0.287 mol/L = 7.32 × 10⁻³ mol

Step 4: Calculate the reacting moles of HClO₄

7.32 × 10⁻³ mol Ba(OH)₂ 2 mol HClO₄/1 mol Ba(OH)₂ = 0.0146 mol HClO₄

Step 5: Calculate the concentration of HClO₄

0.0146 moles of HClO₄ are in 8.99 mL of solution.

[HClO₄] = 0.0146 mol/0.00899 L = 1.62 M

Answer:

Examples of isotones include carbon-12, nitrogen-13 and oxygen-14. These atoms all have six neutrons and six, seven and eight protons respectively. A mnemonic that can be used to differentiate isotones from isotopes and isobars is as follows: same Z (number of protons) = isotopes.

Answer:

c. NaOH

Explanation:

just took the quiz

Answer: The correct option is C (One of the fatty acid salts was unsaturated, and it completely isomerized under the reaction conditions).

Explanation:

Fats and oils belongs to a general group of compounds known as lipids. Fatty acids are weak acid and are divided into two:

--> Saturated fatty acids: These have NO double bonds in their hydrocarbon chain, and

--> Unsaturated fatty acids: These have one or more double bonds in their hydrocarbon chain.

SAPONIFICATION is defined as the process by which fats and oil is hydrolyzed with caustic alkali to yield propane-1,2,3-triol and the corresponding sodium salt of the component fatty acids. During this process, One hydroxide ion is required to hydrolyze one ester linkage of a triacylglycerol molecule. Because there are three ester linkages in a triacylglycerol, three equivalents of sodium hydroxide will be needed to completely saponify the triacylglycerol. This explains the reason why saponification of the triacylglycerol iresulted in four different fatty acid salts.

Answer:

CH 2 CH 3 CHCH = C6H5 + 5 Hydrogen Atoms

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Explanation:

Efficiency = (output/input)×100%

70% = output/(800 W)

which means

output = 0.70×(800 W) = 560 W

Answer:

75.12 J

Explanation:

Applying,

Q = CΔT................ equation 1

Where Q = amount of heat, C = Heat capacity, ΔT = temperature rise.

From the question,

Given: C = 62.6 J/K, ΔT = 1.20°C

Substitute these values into equation 1

Q = 62.6(1.20)

Q = 75.12 J

Hence the amount of heat it absorbed is 75.12 J

Answer:

-0.08 °C

Explanation:

We can solve this problem by using Charles' law, which states that at constant pressure:

Where in this case:

We input the data:

And solve for T₂:

Finally we convert 273.08 K to Celsius:

Answer:

Yard . I hope this helped:))

Answer:

For (a): The moles of Ar is 16.94 moles

For (b): The moles of [tex]Cl_2[/tex] is 16.94 moles

For (c): The total number of moles in a tank is 23.47 moles

For (d): The mole fraction of Ar is 0.722

For (e): The mole fraction of [tex]Cl_2[/tex] is 0.278

For (f): The partial pressure of Ar is 2.888 atm

For (g): The partial pressure of [tex]Cl_2[/tex] is 1.112 atm

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.  The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of Ar = 675.5 g

Molar mass of Ar = 39.95 g/mol

Plugging values in equation 1:

[tex]\text{Moles of Ar}=\frac{675.5g}{39.95g/mol}=16.91 mol[/tex]

Given mass of [tex]Cl_2[/tex] = 465.0 g

Molar mass of [tex]Cl_2[/tex] = 70.9 g/mol

Plugging values in equation 1:

[tex]\text{Moles of }Cl_2=\frac{465.0g}{70.9g/mol}=6.56 mol[/tex]

Total moles of gas in the tank = [16.91 + 6.56] mol = 23.47 mol

Mole fraction is defined as the moles of a component present in the total moles of a solution. It is given by the equation:

[tex]\chi_A=\frac{n_A}{n_A+n_B}[/tex]        .....(2)

where n is the number of moles

Moles of Ar = 16.94 moles

Total moles of gas in the tank = 23.47 mol

Putting values in equation 2, we get:

[tex]\chi_{Ar}=\frac{16.94}{23.47}\\\\\chi_{Ar}=0.722[/tex]

Total mole fraction of the system is always 1

Mole fraction of [tex]Cl_2[/tex] = [1 - 0.722] = 0.278

Raoult's law is the law used to calculate the partial pressure of the individual gases present in the mixture.

The equation for Raoult's law follows:

[tex]p_A=\chi_A\times p_T[/tex]                  .....(3)

where [tex]p_A[/tex] is the partial pressure of component A in the mixture and [tex]p_T[/tex] is the total partial pressure of the mixture

We are given:

[tex]\chi_{Ar}=0.722\\p_T=4.00atm[/tex]

Putting values in equation 3, we get:

[tex]p_{Ar}=0.722\times 4.00atm\\\\p_{Ar}=2.888atm[/tex]

We are given:

[tex]\chi_{Cl_2}=0.278\\p_T=4.00atm[/tex]

Putting values in equation 3, we get:

[tex]p_{Cl_2}=0.278\times 4.00atm\\\\p_{Cl_2}=1.112atm[/tex]

Answer:

Compound A and compound B are constitutional isomers with molecular formula C3H7Cl.

When compound A is treated with sodium methoxide, a substitution reaction predominates. When compound B is treated with sodium methoxide, an elimination reaction predominates.

Explanation:

Constitutional isomers are the one which differs in the structural formula.

When compound A is treated with sodium methoxide, a substitution reaction predominates.

That means sodium methoxide is a strong base and a strong nucleophile.

But when it reacts with primary alkyl halides it forms a substitution product and when it reacts with secondary alkyl halide it forms mostly elimination product.

The reaction and the structures of A and B are shown below:

Answer:

His results will be skewed because there was more water than stock solution. Which would cause the percentage solution to be less than 50% therefore the density would be less than the actual value.

Explanation:

The solution will have percentage less than that of 50%. Therefore the density would be less than the actual value.

Suppose there should be 50 mL of the solution, and he added 60 mL. So 10 mL of the solution is added more.

Suppose the mass of the solute is m.

Originally, the density is = [tex]$\frac{m}{50}$[/tex]     [tex]\left(\frac{\text{mass}}{\text{volume}}\right)[/tex]

Now after adding extra 10 mL , the density becomes [tex]$\frac{m}{60}$[/tex].

Therefore, [tex]$\frac{m}{50}>\frac{m}{60}$[/tex]

So the density decreases when we add more solution.

Answer:

Carbon is dull, have a low density, and are poor conductors of heat.

Explanation:

Carbon is a non-metal, therefore bearing properties of a non-metal element.

Answer:

-219

Explanation:

1.5(339) - 1.5(485) = -219

The approximate enthalpy change for this substitution reaction is -219 kJ.

In the case of this substitution reaction, we need to find the enthalpy change when NaO₂C₂H₂Cl is converted to NaO₂C₂H₂F.

This reaction involves the breaking of the C-Cl bond and the formation of the C-F bond.

We have to subtract the bond energy of the C-F bond from that of the C-Cl bond and multiply by the number of moles involved.

So we will have;

ΔH= 1.500 mole [339.0  kJ/mol - 485.0 kJ/mol]

ΔH= -219 kJ

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Answer:

The reaction rate increases in direct proportion to the concentration of the reactant in solution - second order reaction

The reaction rate is constant regardless of the amount of reactant in solution - zero order reaction

An increase in the concentration of the reactant in solution causes the reaction rate to increase exponentially - first order reaction

Explanation:

In a second order reaction, the rate of reaction is directly proportional to the concentration of reactants. This implies that, reaction rate varies as the concentration of the reactant in solution varies.

For a zero order reaction, the rate of reaction is independent of the concentration of the reactants in solution. This means that reaction rate is constant regardless of the amount of reactant in solution.

For a first order reaction, the rate of reaction varies exponentially as the concentration of reactants. Hence, an increase or decrease in the concentration of the reactant in solution causes the reaction rate to increase or decrease exponentially.

Answer:

5 atoms form one formula unit of Fe2O3

Explanation:

2 atoms of Fe (Iron)

and 3 atoms of O ( Oxygen)

so total = 3 + 2

= 5

Answer:

fe203 the right answer is thus

Answer:

2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g) + 248kcal

Explanation:

The reaction of the problem occurs as follows:

H2S(g) + O2(g) → H2O(g) + SO2(g)

To balance the reaction we must balance oxygens:

H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g)

To balance the complete reaction:

2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g)

As the energy is evolved, 124kcal are as product in the reactio per mole of H2S. As the balanced reaction contains 2 moles of H2S, the heat evolved is:

124kcal*2 = 248kcal:

2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g) + 248kcal

And this is the balanced equation

Answer:

physical change because the gaseous water is chemically the same as the liquid

Explanation:

Matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.

Generally, matter exists in three (3) distinct or classical phases and these are; solid, liquid and gas.

A physical change can be defined as a type of change that only affects the physical form of a chemical substance (matter) without having any effect on its chemical properties. Thus, a physical change would only affect the physical appearance and properties of a chemical substance (matter) but not its chemical properties.

This ultimately implies that, a physical change result in a change of matter from one form or phase (liquid, solid or gas) to another without a corresponding change in chemical composition.

Hence, the boiling of water is considered to be a physical change because the gaseous water is chemically the same as the liquid i.e there isn't any changes in chemical composition of water when boiling.

Answer:

Add some water to his solution

Explanation:

Ion pair effect refers to strong electrostatic interaction between oppositely charged ions in solution. Such strong interaction affects solute- solvent interaction when an ionic substance is dissolved in water.

High solute concentration may lead to ion-pair effect. Hence, the ion pair effect may be minimized by adding more water (decreasing the concentration of the solution).

To reduce the ion- pair effect, Andy needs to add some water to his solution (dilution).

The activity that would reduce the ion-pairing effect in his AICI₃ solution is : ( B ) add some water to his solution

Ion pair effect is a strong electrostatic interaction seen between ions with opposite charges, when an ionic substance is been dissolved in a solvent such as water this effect will affect the dissolution of the substance.

High concentration of the solute in a solution also leads to the ion pair effect therefore for Andy to reduce the ion-pairing effect in his solution he has to add more water to reduce the concentration of the solute.

Hence we can conclude that The activity that would reduce the ion-pairing effect in his AICI₃ solution is to add some water to his solution

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Step 1: Represent a molecular formula.

[tex]\text{molecular formula} = (\text{CH}_{2}\text{N}_{2})_{n}[/tex]

Step 2: Calculate the empirical mass.

empirical mass = (12.0 g/mol × 1) + (1.0 g/mol × 2) + (14.0 g/mol × 2)

empirical mass = 42.0 g/mol

Step 3: Divide the molecular mass by the empirical mass.

[tex]n = \frac{\text{molecular mass}}{\text{empirical mass}}[/tex]

[tex]n = \frac{\text{126.0}}{\text{42.0}}[/tex]

[tex]n = 3[/tex]

Step 4: Multiply the subscripts by the value of n to obtain the molecular formula.

[tex]\text{molecular formula} = (\text{CH}_{2}\text{N}_{2})_{3}[/tex]

[tex]\boxed{\text{molecular formula} = \text{C}_{3}\text{H}_{6}\text{N}_{6}}[/tex]

[tex]\\[/tex]

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Answer:

Farmers spray to mitigate crop damage caused by pests. A pest is any biological organism, including weeds, pathogens, and arthropods, that interferes with the production of crops affecting quality and/or yield. ... Pesticides work in many different ways by affecting their target, whether it be a weed, pest, or disease.

Explanation:

this is my answer❤︎

Answer:

8

Explanation:

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