What was the resulting molarity of your primary standard solution of potassium iodate kio3?

Answers

Answer 1
Missing question: 0,535 gram of KIO₃ dissolved in 250 mL of de-ionized water to make primary standard solution.
m(KIO₃) = 0,535 g.
V(KIO₃) = 250 mL ÷ 1000 mL/L = 0,25 L.
n(KIO₃) = m(KIO₃) ÷ M(KIO₃).
n(KIO₃) = 0,535 g ÷ 214 g/mol.
n(KIO₃) = 0,0025 mol.
c(KIO₃) = n(KIO₃) ÷ V(KIO₃).
c(KIO₃) = 0,0025 mol ÷ 0,25 L.
c(KIO₃) = 0,01 mol/L = 0,01 M.

Related Questions

A solution of naoh(aq) contains 11.6 grams of naoh in 129 ml of solution. calculate the ph at 25◦c.

Answers

First, we need to determine the number of moles of NaOH:

n(NaOH) = m/M = 11.6/40 = 0.29 mole

Then, the concentration of NaOH solution can be calculated: 

c(NaOH) = n/V = 0.29/0.129 = 2.25 mol/L

The concentrations of NaOH and OH⁻ ions are equal, so we can determine pOH:

pOH = -log[OH⁻] = -log2.25 = -0.35

Finally, pH value is:

pH + pOH = 14

pH = 14 - (-0.35) = 14.35

For the reaction bro3- + 5br- + 6h+ → 3br2 + 3h2o at a particular time, -δ [bro3-]/δt = 1.5 × 10-2 m/s. what is -δ [br-]/δt at the same instant?

Answers

The $  -(Br)   at  that  instant   is  calculated  as  follows
BrO3  + 5Br  --->  3Br2  +  3 H2o

by   use    of  reacting  ratio  BrO3   to  Br2  which   is   1:3

therefore   $  of  Br  =  3  x   (1.5 x10^-2)= 4.5 x10^-2

Answer:

7.5 M/s

Explanation:

The equation of Reaction is given as;

BrO^3- + 5Br^- + 6H^+ --------------> 3Br2 + 3H2O. ----------------------------(1)

Rate of Reaction is the speed in which reaction take place for the transformation of reactants to products.

For the reaction (1) above;

===> - (∆[BrO^3-]/ ∆t) = -(∆Br^-])/∆t = -∆[H^+] /∆t = ∆[Br2]/∆t.

Notice from above that there is negative signs at the Change in the reacti species. This is so, because the Reactants is been used up in the reaction to produce the products

NB : I did not raise the number of the moles to the power of each species to avoid clumsiness.

We are given that; - (∆[BrO^3-]/ ∆t) = 1.5 × 10^-2 m/s; -(∆Br^-])/∆t = x m/s.

1 mole of BrO3^- = 5 mole of Br^-

So, 5 × 1.5 ×10^-2 .

= 7.5 × 10 ^-2 M/s

Write a speech aimed at year 7 to explain why some metals lose their shine over time but gold does not.

Answers

The reason of why some metals lose their shine over time but the gold does not is so simple that's because the corrosion and tarnish processes. Metals donate  electrons when exposed to atmosphere and tends to form oxide. and when the metal donate electrons the oxygen tends to accept this electrons and fill up its shell and form oxide and the metal lose its shine.when the oxide film contact with an aqueous medium metal oxide pairs with H2O and form rust.

But gold is a noble metal (like platinum and silver), it remains stable in its pure form and doesn't donate electrons so, no loss electrons and the oxide don't happen at all. So the gold is known for its resistance to oxidation. As the noble metals have a very low reaction rate with oxygen, So there is no rusting as the rusting is the result of the reaction of the oxygen with the metals.So there is no tarnish appears. that's why the gold doesn't lose its shine and keeps its pure form.

The concentration of ag+ in a solution saturated with ag2c2o4(s) is 1.7 × 10-4 m. calculate ksp for ag2c2o4.

Answers

Silver oxalate dissociation equation is following: 

Ag₂C₂O₄(s) ⇄ 2Ag⁺(aq) + C₂O₄²⁻(aq)

According to reaction follows next stoichiometric ratio:

[Ag⁺] : [C₂O₄²⁻] = 2 : 1

[C₂O₄²⁻] = [Ag⁺] / 2

[C₂O₄²⁻] = (1.7×10⁻⁴)/2 = 8.5×10⁻⁵ M

So, solubility product constants for silver oxalate is:

Ksp = [Ag⁺]² x [C₂O₄²⁻]

Ksp = [1.7×10⁻⁴]² x [8.5×10⁻⁵]

Ksp = 2.46×10⁻¹²



At a certain temperature, a 21.0-l contains holds four gases in equilibrium. their masses are: 3.5 g so3, 4.6 g so2, 13.5 g n2, and 0.98 g n2o. what is the value of the equilibrium constant at this temperature for the reaction of so2 with n2o to form so3 and n2 (balanced with lowest whole-number coefficients)?

Answers

SO2 +N2O<--->SO3+N2
Kc =  concentration   of  product /concentration  of  reactant
(SO3)(N2/(SO2)(N2O)
Find  the  concentration  of  each reactant  and  products
concentration =number  of  moles/  volume  in  liters
 moles  of SO3=  3.5/80=0.044moles
SO2=4.6/64=0.072 moles
N2=13.5/28=0.483  moles
N2O=0.98/44=0.022 moles
concentration  is  therefore=
SO3=0.044/21=  2.095  x  10^-3
SO2=0.072 /21=3.43 x  10^-3
N2=0.483/21=0.023
N2O=0.022/22= 1.048 x 10^-3

Kc   is  therefore  ={ (2.095 x10^-3)(0.023)}/ {(3.43 x10^-3)(1.048  x10^-3)}=13.40


Final answer:

Equilibrium constant values are crucial in determining the extent of a reaction. Calculations involving equilibrium constants help predict reaction outcomes and concentrations at equilibrium.

Explanation:

Equilibrium Constant (K) is a value that indicates the extent to which a reaction will proceed at a certain temperature. It is calculated using the concentrations of products and reactants at equilibrium. The equilibrium constant is specific to a particular reaction at a specific temperature.

For the reaction SO₂(g) + NO₂(g) → SO₃(g) + NO(g), the equilibrium partial pressure for SO₃ can be calculated using the equilibrium constant (K) value and the initial partial pressures of the gases involved. By plugging in the given values and using the equation for K, you can find the equilibrium partial pressure for SO₃.

Given the reaction 2 SO₂(g) + O₂(g) → 2 SO₃(g) with an equilibrium constant of 7.9 x 10¹, you can calculate the equilibrium constant for the reverse reaction by taking the reciprocal of the original equilibrium constant. This allows you to determine the equilibrium constant for the reverse reaction at the same temperature.

Select all that apply. Atoms are made up of _____. neurons photons protons neutrons

Answers

Hello!

Atoms are made of 3 types of particles: Electrons, protons, and neutrons. The protons and neutron (referred to collectively as nucleons) make up the nucleus (center) of the atom, while the electrons surround the nucleus.

Answer:
Protons, neutrons, and electrons.

why did the president say the humans need to stay in space wall-e

Answers

In the distant future, earth was no longer habitable by humans due to extreme pollution and excessive waste. Humans were not allowed to go back to earth due to the severity of the planet's condition and they dwell in space for hundreds of years while WALL-E, short for Waste Allocation Load Lifter Earth-class, was the only robot left to clean the planet, little by little.

What is the boiling point of oxygen? a. 100 degrees C c. -57 degrees C b. 8 degrees C d. -183 degrees C Please select the best answer from the choices provided A B C D

Answers

-183 degrees C is the answer

What is the change in oxidation number of sulfur when the dithionite anion, s2o42−, is converted to so2 in an oxidation-reduction reaction? does each sulfur atom gain or lose electrons in the reaction? is sulfur oxidized or reduced in the reaction?

Answers

1) In dithionite anion (S₂O₄²⁻) sulfur has oxidation number +3, because oxygen has oxidation number -2, so:
2 · x + 4 ·(-2) = -2.
2x = +6.
x = +3; oxidation number of sulfur.
In sulfur(IV) oxide (SO₂), sulfur has oxidation number +4, because oxygen is again -2 and compound has neutral charge:
x + 2 · (-2) = 0.
x = +4.
Change in sulfur is from +3 to +4.
Sulfur atoms lose electrons in the reaction. Sulfur is oxidized in the reaction, because his oxidation number raise from +3 to +4.

A sample of potassium chlorate (15.0 g) is dissolved in 201 g of water at 70 °c with precautions taken to avoid evaporation of any water. the solution is cooled to 30.0 °c and no precipitate is observed. this solution is __________.
a.hydrated

Answers

Answer is: unsaturated.
Solubility of potassium chlorate on 70°C is approximately 30 grams in 100 grams of water.
Solubility of potassium chlorate on 70°C is approximately 10 grams in 100 grams of water.
So if dissolve 15 g of potassium chlorate in 201 g of water, there is less salt than it solubility and solution is unsaturated.
Final answer:

The potassium chlorate remains fully dissolved in the water even when the temperature is lowered, thus the solution is considered to be saturated.

Explanation:

The potassium chlorate in the question is fully dissolved in water at a certain temperature (70°C) and it stays in solution even when the temperature is lowered to 30°C. This indicates that the complete dissolution of the potassium chlorate was achieved, and the solution is considered to be saturated. A saturated solution is one in which the maximum amount of solute has been dissolved in a solvent at a given temperature and below that temperature, no precipitate forms because the solute remains in solution.

Learn more about Saturated Solution here:

https://brainly.com/question/1851822

#SPJ11

A student was titrating the calcium and water solution and notice the formation of bubbles in the flask. which description would best describe what is occuring?

Answers

Final answer:

Bubbles forming during a reaction involving calcium and water suggests a chemical reaction is occurring, likely the formation of solid calcium hydroxide or the release of carbon dioxide gas if an acid is present.

Explanation:

The student has observed the formation of bubbles while titrating a solution of calcium and water. This observation indicates that a chemical reaction is taking place. When solid calcium oxide reacts with liquid water, as per the information provided, the result is the formation of solid calcium hydroxide. This exothermic reaction may release gas and cause bubbling. Another possibility could be the formation of calcium carbonate and the release of carbon dioxide gas when reacting with an acid, which also leads to bubbling.

The pH scale runs from 0 to 14, and is an indication of how acidic or basic a solution is. A pH close to zero indicates a(n) _______ solution, and a pH near 14 indicates a(n) _______ solution.

Answers

acidic, basic. Also, 7 is neutral. Hope it helps! :)

Explanation:

A pH scale is a scale which helps in identifying whether a given substance is basic, acidic or neutral in nature.

So, when a substance has pH value less then 7 then it means the substance is acidic in nature. Whereas when a substance has pH value more then 7 then it means the substance is basic in nature.

On the other hand, if pH value of a substance is equal to 7 then it means the substance is neutral in nature.

Hence, we can conclude that the pH scale runs from 0 to 14, and is an indication of how acidic or basic a solution is. A pH close to zero indicates an acidic solution, and a pH near 14 indicates a basic solution.

The equilibrium concentrations were found to be [h2o]=0.250 m, [h2]=0.370 m, and [o2]=0.750 m. what is the equilibrium constant for this reaction

Answers

Answer:

Kc = 1.28

Explanation:

Let's consider the following reversible reaction.

H₂O(g) ⇄ H₂(g) + 0.5 O₂(g)

The equilibrium constant (Kc) is the product of the concentrations of the products raised to their stoichiometric coefficients divided by the product of the concentration of the reactants raised to their stoichiometric coefficients.

[tex]Kc=\frac{[H_{2}][O_{2}]^{0.5}}{[H_{2}O]} =\frac{(0.370).(0.750)^{0.5}}{0.250} =1.28[/tex]

If the solubility of o2 at 0.370 atm and 25 °c is 15.3 g/100 g h2o, what is the solubility of o2 at a pressure of 2.40 atm and 25 °c?

Answers

According to Henry's law:

C = K P         when,
C is the solubility of a gas at a constant temperature in a particular solvent.
K is the Henry law constant 
p is the pressure of the gas

we have the pressure and the solubility so we will get the K at first:
by substitution:
0.153 = K * 0.37atm 
K= 0.4
∴ C when P = 2.4 atm
∴ C = 0.37 * 2.4 atm = 0.888   = 88.8 g/100g H2O


Final answer:

The solubility of O2 in water is directly proportional to the partial pressure of the gas. To find the solubility of O2 at a pressure of 2.40 atm, we can use Henry's law and the given solubility at 0.370 atm.

Explanation:

Solubility of O2 in water at different pressures

The solubility of oxygen (O2) in water is directly proportional to the partial pressure of oxygen gas above the water. This relationship is described by Henry's law. According to Henry's law, the solubility of a gas is equal to the product of the Henry's law constant (kH) and the partial pressure of the gas. Therefore, to find the solubility of O2 at a pressure of 2.40 atm and 25 °C, we can use the following equation:

Solubility = kH * Pressure

Given that the solubility of O2 at 0.370 atm and 25 °C is 15.3 g/100 g H2O, we can rearrange the equation to solve for the Henry's law constant:

kH = Solubility / Pressure

Substituting the values into the equation, we get:

kH = (15.3 g/100 g H2O) / 0.370 atm

Solving this equation will give us the value of kH. Once we have the value of kH, we can use it to calculate the solubility of O2 at a pressure of 2.40 atm.

In what physical state does acetic acid exist at 393 k?

Answers

The answer is gas state
- when the boiling point of acetic acid = 118 C°
So to know the state we should convert the acetic acid temperature from Kelvin to C° 
when T by Kelvin = 393 K, So it will be 393 - 273 = 120 C°
So the temperature here is higher than the boiling point 
∴ the answer will be gas state

Final answer:

At 393 K, which is 119.85°C, acetic acid exists in a liquid state, as it is above its melting point and below its boiling point.

Explanation:

Acetic acid, also known by its systematic name ethanoic acid, exists in different physical states depending on the temperature. Pure acetic acid solidifies at 16.6°C and is referred to as glacial acetic acid because it often solidified in cold laboratories lending the appearance of ice. At 393 K (which is equivalent to 119.85°C), acetic acid is well above its melting point and well below its boiling point of about 118°C. Hence, at 393 K, acetic acid would exist in a liquid state. It is important to note that the compound forms dimers due to strong intermolecular hydrogen bonding, which affects its physical properties, including melting and boiling points.

For each item: classify organic or inorganic. NaCl: . phenol (C6H6;O): . C2H6: . Ca3(PO4)2: . formaldehyde (CH20): . MgCO3: .

Answers

NaCl - inorganic
Phenol - organic
C2H6 - organic
Ca3(PO4)2 - inorganic
CH2O - Organic
MgCO3 - Organic
Basically, if it has Carbon (other than a few) it is organic.

Explanation:

It is known that compound that contain carbon atom and hydrogen atom which are combined together are known as organic compounds. Carbon atom is the main element present in an organic compound.

For example, [tex]C_{6}H_{6}[/tex] is an organic compound.

Whereas compounds that does not contain carbon atom are known as inorganic compounds.

Thus, we can conclude that given compounds are classified as follows.

Organic compounds : [tex]C_{6}H_{6}[/tex], [tex]C_{2}H_{6}[/tex], [tex]CH_{2}O[/tex], and [tex]MgCO_{3}[/tex].

Inorganic compounds : [tex]Ca_{3}(PO_{4})_{2}[/tex].

What is the osmotic pressure of a solution made by dissolving 75.0 g of glucose, c6h12o6, in enough water to form 700.0 ml of solution at 45.0 ∘c ? express your answer to three significant figures and include the appropriate u?

Answers

we will use the osmotic pressure formula:
π = n R T / V
When π is the osmotic pressure (atm)
n is no.of moles when the molar mass of glucose = 180 g/mol
so, n = 75 g / 180 g/mol= 0.42

and R is gas constant = 0.0821 L.atm/mol.k 
T is the temperature in Kelvin = 45 +273 = 318 K
and V is the volume in Litre = 700 / 1000 = 0.7 L
So, by substitution:
∴ π = 0.42 * 0.0821 * 318 / 0.7 = 15.665 atm

You have an aqueous solution where [OH-] = 1 x 10^-13 mol/L.

A.Calculate the hydrogen ion concentration [H+]. Show all work.
B.Calculate the pH. Show all work.
C.Is this solution an acid, base, or neutral and how do you know?

I honestly have no clue how to do this... please help... I will help you one something!! PLEASE

Answers

1) Answer is: the hydrogen ion concentration is 1·10⁻¹ mol/L.
[OH⁻] = 1·10⁻¹³ mol/L, equilibrium concentration of hydroxide anion.
[H⁺] is the concentration of hydrogen ions.
[OH⁻] · [H⁺] = 10⁻¹⁴ mol²/L², ionicproduct of water on room temperature.
[H⁺] = 10⁻¹⁴ mol²/L² ÷  1·10⁻¹³ mol/L.
[H⁺] = 10⁻¹ mol/L = 0,1 mol/L.

2) pH = -log[H⁺], approximately the negative of the base 10 logarithm of the molar concentration of hydrogen ions
pH = -log(10⁻¹ mol/L).
pH = 1.
This solution is acid, because pH value (potential of hydrogen) is less than seven. If pH is greater than seven, slotion is base and if pH is equal seven, solution is neutral.

The hydrogen ion concentration [H⁺] is 0.1 mol/L, making the pH of the solution 1. This pH level indicates that the solution is acidic.

Let's work through the problem step by step:

A. Calculate the hydrogen ion concentration [H⁺]

We know that the product of hydrogen ion concentration [H⁺] and hydroxide ion concentration [OH⁻] in water is equal to 1 x 10⁻¹⁴ at 25°C. This is represented by the equation:

[H⁺] * [OH⁻] = 1 x 10⁻¹⁴

Given that [OH⁻] = 1 x 10⁻¹³ mol/L, we can rearrange the equation to solve for [H⁺]:

[H⁺] = 1 x 10⁻¹⁴ / [OH⁻]

Substituting the given value:

[H⁺] = 1 x 10⁻¹⁴ / 1 x 10⁻¹³ = 1 x 10⁻¹ = 0.1 mol/L

B. Calculate the pH

The pH of a solution is calculated using the formula:

pH = -log[H⁺]

Substituting the value for [H⁺]:

pH = -log(0.1) = 1

C. Identify if the solution is an acid, base, or neutral

A solution with a pH less than 7 is acidic, a pH greater than 7 is basic, and a pH of 7 is neutral.

Since the pH of this solution is 1, it is an acidic solution.

Which of the following equilibrium systems most favors the products? a) CI2(g) + 2NO2(g) 2NO2CI(g); Keq = 1.8 b) N2(g) + 3H2(g) 2NH3(g); Keq = 345 c) 2HCI2(g) H2(g) + CI2(g); Keq = 2.0 × 10-7 d) CI2(g) + 2NO(g) 2NOCI(g); Keq = 3.7 × 108

Answers

CI2(g) + 2NO(g)  2NOCI(g); Keq = 3.7 × 10^8

Answer: The correct answer is Option d.

Explanation:

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as [tex]K_{eq}[/tex]

For a general chemical reaction:

[tex]aA+bB\rightarrow cC+dD[/tex]

The expression for [tex]K_{eq}[/tex] is written as:

[tex]K_{eq}=\frac{[C]^c[D]^d}{[A]^a[B]^b}[/tex]

There are 3 conditions:

When [tex]K_{eq}>1[/tex]; the reaction is product favored.When [tex]K_{eq}<1[/tex]; the reaction is reactant favored.When [tex]K_{eq}=1[/tex]; the reaction is in equilibrium.

From the above expression, the equilibrium constant is directly dependent on product concentration. Thus, more is the concentration of product, more will be the equilibrium constant.

The highest values of [tex]K_{eq}[/tex] will favor the product more.

Hence, the correct answer is Option d.

Complete the equations showing how 2−phenylethanol (c6h5ch2ch2oh) could be prepared from 2−phenylethanoic acid (c6h5ch2co2h) as the starting material.

Answers

2-Phenylethanol is prepared from 2-phenylethanoic acid by reducing the carboxylic acid group using lithium aluminum hydride (LiAlH4). The reaction replaces the oxygen in the carboxyl group with a hydrogen, yielding the alcohol.

The conversion of 2-phenylethanoic acid (C6H5CH2CO2H) to 2-phenylethanol (C6H5CH2CH2OH) involves a reduction reaction. One common method to achieve this transformation is to use a reducing agent, such as lithium aluminum hydride (LiAlH4). Here's the reaction:

[tex]\[ \text{C}_6\text{H}_5\text{CH}_2\text{CO}_2\text{H} + \text{LiAlH}_4 \rightarrow \text{C}_6\text{H}_5\text{CH}_2\text{CH}_2\text{OH} + \text{LiAl(OH)}_4 \][/tex]

In this equation:

- C6H5CH2CO2H represents 2-phenylethanoic acid.

- LiAlH4 is lithium aluminum hydride, a powerful reducing agent.

- C6H5CH2CH2OH represents 2-phenylethanol.

- LiAl(OH)4 is lithium aluminum tetrahydroxide, a byproduct of the reduction.

This reaction reduces the carboxylic acid group in 2-phenylethanoic acid to the alcohol group in 2-phenylethanol. The reduction involves the addition of hydrogen (H) from LiAlH4 to the carbon-oxygen double bond of the carboxylic acid, resulting in the formation of the alcohol.

The synthesis of 2-phenylethanol from 2-phenylethanoic acid involves reducing the acid to the corresponding alcohol using sodium borohydride (NaBH₄) as a reducing agent. This reaction converts the 2-phenylethanoic acid to 2-phenylethanol with the release of water.

The preparation of 2-phenylethanol (C₆H₅CH₂CH₂OH) from 2-phenylethanoic acid (C₆H₅CH₂CO₂H) can be carried out through the following steps:

Reduction of 2-phenylethanoic acid to 2-phenylethanol: This reaction involves the conversion of the acid to the corresponding alcohol. Sodium borohydride (NaBH₄) can be used as a reducing agent.

2-phenylethanoic acid is reduced to 2-phenylethanol using sodium borohydride:

C₆H₅CH₂CO₂H + 4[H] → C₆H₅CH₂CH₂OH + H₂O

In this reaction, sodium borohydride (NaBH₄) serves as the source of hydrogen (H).

This completes the transformation of 2-phenylethanoic acid to 2-phenylethanol.

Tin has many possible isotopes. three of these isotopes are 115sn, 117sn, and 126sn. what is the mass number of each? how many protons, neutrons, and electrons are present in each?

Answers

Isotopes of an atom is the same atom but the difference between them is that the number of neutrons in the nucleus would differ, depending on the mass number. So let's take a look at your problem and breakdown Tin.

A stable atom of Tin (Sn):
Atomic number: 50
Protons: 50
Electrons:50
Neutrons: 69
Mass Number: 119 (rounded-off)

The Mass number is equal to the sum of protons and neutrons.
Now in an isotope, everything is the same, except for the number of neutrons. We can solve for how many neutrons an isotope has base on the mass number. 

A = p + n
Where A= Mass number
            p = proton
            n = neutron

To get the number of neutron just get the difference between the mass number and proton.
n = A - p

For your given, the mass number is already indicated.

*Note that isotopes have the same number of electrons, protons and atomic number as the original atom. 
 
1. 115 Sn or Tin 115 
Atomic number: 50 
Protons:    50
Electrons: 50 
Neutrons: ?
Mass number: 115

Now we get the number of neutrons:

n = A - p
n = 115 - 50
n  = 65

So 115Sn has a mass number of 115, 50 protons, 50 electrons and 65 neutrons.

2. 117 Sn or Tin-117
Atomic number: 50 
Protons:    50
Electrons: 50 
Neutrons: ?
Mass number: 117

Now we get the number of neutrons:

n = A - p
n = 117 - 50
n  = 67

So 117Sn has a mass number of 117, 50 protons, 50 electrons and 67 neutrons.

3. 126 Sn or Tin-126
Atomic number: 50 
Protons:    50
Electrons: 50 
Neutrons: ?
Mass number: 126

Now we get the number of neutrons:

n = A - p
n = 126 - 50
n  = 76

So 126Sn has a mass number of 126, 50 protons, 50 electrons and 76 neutrons.
Final answer:

The atomic number of tin is 50, and the mass numbers of the tin isotopes are 115, 117, and 126. Each isotope has 50 protons, and the number of neutrons varies for each isotope. All isotopes of tin have 50 electrons.

Explanation:

The atomic number of an element represents the number of protons in the nucleus. So, for tin, which has an atomic number of 50, it means there are 50 protons in its nucleus.

The mass number of an isotope is the sum of the number of protons and neutrons in the nucleus. For the isotopes given, 115Sn has a mass number of 115, 117Sn has a mass number of 117, and 126Sn has a mass number of 126.

Since the number of protons in an atom is equal to the atomic number, each isotope of tin will have 50 protons. The number of neutrons is equal to the mass number minus the atomic number. So, 115Sn has 65 neutrons, 117Sn has 67 neutrons, and 126Sn has 76 neutrons. The number of electrons in a neutral atom is equal to the number of protons, so each isotope will also have 50 electrons.

What is the density of a piece of metal in g/cm3 if its mass is determined to be 42.20 g and it is in the shape of a cube, with edge length of 2.50 cm?

Answers

It's a cube so the volume = edge^3
Volume = 2.5^3 cm^3 = 15.625 cm^3

density = mass / volume = 42.20 / 15.625 = 2.70 You have 3 places of accuracy.

density of object = 2.70 grams / cm^3 <<<<=== answer.

Answer : The density of a piece of metal is [tex]2.7008g/cm^3[/tex]

Explanation :

To calculate the volume of cube, we use the formula:

[tex]V=a^3[/tex]

where,

a = edge length of cube

Given :

Edge length of cube = 2.50 cm

Volume of cube = [tex](2.50cm)^3=15.625cm^3[/tex]

Given :

Mass of metal = 42.20 g

To calculate density of a substance, we use the equation:

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

Putting values in above equation, we get:

[tex]\text{Density of metal}=\frac{42.20g}{15.625cm^3}=2.7008g/cm^3[/tex]

Hence, the density of a piece of metal is [tex]2.7008g/cm^3[/tex]

Changes in the price level affect which components of aggregate demand?

a. only consumption and investment

b. only consumption and net exports

c. only investment

d. consumption, investment, and net exports

Answers

The correct option is D.
Aggregate demand refers to the total demand for goods and services within a particular market. The components of aggregate demand include: consumption, investment, government spending and net export. Changes in the price level affect consumption, investment and net export.


All organisms need energy from food in order to survive. Plants produce their own food through photosynthesis. Animals must find external sources for food.

Which of the following is true?
A.
Plants are autotrophs, and animals are heterotrophs.
B.
Plants and animals are both autotrophs.
C.
Plants and animals are both heterotrophs.
D.
Plants are heterotrophs, and animals are autotrophs.

Answers

A. plants are autotrophs and animals are heterotrophs
the correct answer is A

A uranium and iron atom reside a distance r = 42.30 nm apart. the uranium atom is singly ionized; the iron atom is doubly ionized. calculate the distance r from the uranium atom necessary for an electron to reside in equilibrium. ignore the insignificant gravitational attraction between the particles

Answers

Using this equation:

E(U) = E(Fe) kq / r² = k2q / (R-r)² 1/r² = 2/(R-r)²

(R-r)² = 2r² 

R² - 2Rr + r² = 2r² 

r² + 2Rr - R² = 0 is a quadratic equation to solve 
r² + 84.6r - 1789 = 0 ► solving for the quadratic equation

r² x 10 + 84.6r x 10 - 1789 x 10 = 0 x 10

refining: 10r² + 846r - 17890 = 0
so a = 10, b = 846, and c = -17890

r = -846 + √846² - 4 x 10 (-17890) / 2 x 10

r = 17.52 nm

Write the name of the following compound: H3PO4

Answers

Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is a mineral acid with the chemical formula H3PO4

Explanation:

Since the given formula is [tex]H_{3}PO_{4}[/tex]. It consists of three hydrogen atoms, one phosphorous atom and four oxygen atoms.

[tex]H_{3}PO_{4}[/tex] is known as phosphoric acid. It is a weak acid and it dissociates to give hydrogen ions when dissolved in a solvent.

Phosphoric acid ([tex]H_{3}PO_{4}[/tex]) is also known as orthophosphoric acid.

Two chemicals a and b are combined to form a chemical
c. the rate, or velocity, of the reaction is proportional to the product of the instantaneous amounts of a and b not converted to chemical
c. initially, there are 100 grams of a and 50 grams of b, and for each gram of b, 2 grams of a is used. it is observed that 15 grams of c is formed in 10 minutes. how much is formed in 40 minutes? (round your answer to one decimal place.) grams

Answers

-dB/dt = kAB = k(2B)(B) = 2kB^2
-dB/B^2 = 2kdt
Integrating: 1/B - 1/(B_0) = 2kt
At t = 10, if 15 g of C have formed, this must have consumed 10 g A and 5 g B. The remaining mass of B is 45 g.
1/45 - 1/50 = 2(k)(10)
k = 1.11 x 10^-4
Then substituting this value of k with t = 40:
1/B - 1/50 = 2(1.11 x 10^-4)(40)
1/B - 1/50 = 0.008889
1/B = 0.028889
B = 34.62 g remaining
Therefore, 50 - 34.62 = 15.38 g of B have been consumed.
Doubling, 30.76 g of A have been consumed.
This means that 15.38 + 30.76 = 46.15 g of C have been formed.

The reaction 2a → a2​​​​​ was experimentally determined to be second order with a rate constant, k, equal to 0.0265 m–1min–1. if the initial concentration of a was 4.25 m, what was the concentration of a (in m) after 180.0 min?

Answers

according to the second order formula:
1/[At] = K t + 1/[Ao]
and when we have the K constant =0.0265 & we have t = 180 min & we have the initial concentration of A = 4.25 so by substitution:

1/[At]  = 0.0265 X 180min + 1/4.25 
1/[At] = 5
∴[At] = 1/5 = 0.2 m

Answer : The final concentration was 0.199 M

Explanation :

The expression used for second order kinetics is:

[tex]kt=\frac{1}{[A_t]}-\frac{1}{[A_o]}[/tex]

where,

k = rate constant = [tex]0.0265M^{-1}min^{-1}[/tex]

t = time = 180.0 min

[tex][A_t][/tex] = final concentration = ?

[tex][A_o][/tex] = initial concentration = 4.25 M

Now put all the given values in the above expression, we get:

[tex]0.0265\times 180.0=\frac{1}{[A_t]}-\frac{1}{4.25}[/tex]

[tex][A_t]=0.199M[/tex]

Therefore, the final concentration was 0.199 M

scientific description about the pizza dough doubles its size when it is placed in a warm place . how does this happen

Answers

Answer is: because carbon(IV) oxide is released.
For example if baking soda is used for the pizza dough, than on heat carbon(IV) oxide is product of chemical reaction:
2NaHCO₃ → Na₂CO₃ + CO₂ + H₂O.
If we use yeast (single-celled microorganism), also carbon(IV) oxide produced, because yeast turns sugars into carbon(IV) oxide.

The thermal isomerization of cyclopropane to propene has a rate constant of 5.95 × 10−4 s−1 at 500oc. calculate the value of the gibbs energy of activation, ∆g⊖‡ for this reaction.

Answers

Using the Arrhenius equation and an estimated pre-exponential factor, we calculated the Gibbs energy of activation for cyclopropane isomerization to be 161,226 J/mol. This value indicates the energy barrier that molecules need to overcome for the reaction to proceed.

Calculation of Gibbs Energy of Activation for Cyclopropane Isomerization

The thermal isomerization of cyclopropane to propene requires overcoming an energy barrier, represented by the Gibbs energy of activation, ΔG⁰‡. We can calculate this value using the Arrhenius equation and the provided rate constant at a specific temperature.

Steps:

Convert temperature to Kelvin: T = 500°C + 273.15 K = 773.15 K

Plug values into the Arrhenius equation:

k = A * exp(-ΔG⁰‡ / RT)

where:

k = rate constant (5.95 × 10^-4 s^-1)

A = pre-exponential factor (unknown)

R = gas constant (8.314 J/mol·K)

T = temperature (773.15 K)

Rearrange the equation to solve for ΔG⁰‡:

ΔG⁰‡ = -RT * ln(k / A)

Estimate the pre-exponential factor: A for this reaction is typically in the range of 10^8 - 10^13 s^-1. For our calculation, assume A = 10^10 s^-1.

Calculate ΔG⁰‡:

ΔG⁰‡ = -8.314 J/mol·K * 773.15 K * ln(5.95 × 10^-4 s^-1 / 10^10 s^-1) = 161,226 J/mol

Therefore, the Gibbs energy of activation for the thermal isomerization of cyclopropane to propene is approximately 161,226 J/mol.

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