What is the oxidation number of the chromium atom in k2cro4? what is the oxidation number of the chromium atom in ? +2 +6 -3 -7 +4?

Answers

Answer 1
(K⁺¹)2Cr(O⁻²)4

+1*2 +x-2*4=0
2+x-8=0
x=6
Oxidation number of Cr is +6.

Related Questions

a student reacts 0.600 g of lead (ii) nitrate with 0.850 g of potassium iodide

write and balance the chemical equation.

how many miles of Pb(No3)2 were used?

how many miles of KI were used?

how many miles of PbI2 would form based on the moles of Pb(No3)2 used?

how many miles of PbI2 would form based on the moles of KI used?

which is the limiting reactant?

what is the theoretical yeild of PbI2 in grams?

if the student obtained 0.475 grams of PbI2 product after conducting it by filtration, what is the percent yeild of PbI2 obtained ?

Answers

Q1)
the reaction that takes place is 
lead nitrate reacting with potassium iodide to form lead iodide and potassium nitrate 
balanced chemical equation for the reaction is as follows
Pb(NO₃)₂ + 2KI ----> PbI₂  + 2KNO₃

Q2)
mass of lead nitrate present - 0.600 g 
number of moles = mass present / molar mass 
number of moles - 0.600 g / 331.2 g/mol = 0.00181 mol 

Q3)
mass of potassium iodide present - 0.850 g
number of moles = mass present / molar mass
number of moles of potassium iodide = 0.850 g / 166 g/mol = 0.00512 mol

Q4)
we have to calculate the number of moles of PbI₂ formed based on the number of moles of Pb(NO₃)₂ present assuming the whole amount of Pb(NO₃)₂ was used up 
stoichiometry of Pb(NO₃)₂ to PbI₂ is 1:1
number of Pb(NO₃)₂ moles reacted - 0.00181 mol
therefore number of PbI₂ moles formed - 0.00181 mol 


Q5)
next we have to calculate the number of moles of PbI₂ formed based on the amount of KI moles present , assuming all the moles of KI were used up in the reaction 
stoichiometry of KI to PbI₂ is 2:1
number of moles of KI reacted - 0.00512 mol
then number of moles of PbI₂ formed - 0.00512 x 2 = 0.0102 mol
0.0102 mol of PbI₂ is formed 

Q6)
limting reactant is the reactant that is fully consumed during the reaction. the amount of product formed depends on the amount of limiting reactant present

if lead nitrate is the limiting reactant 
if 1 mol of Pb(NO₃)₂ reacts with 2 mol of KI 
then 0.00181 mol of Pb(NO₃)₂ reacts with - 2 x 0.00181 mol of KI = 0.00362 mol 
but 0.00512 mol of KI is present and only 0.00362 mol are required 
therefore KI is in excess and Pb(NO₃)₂ is the limiting reactant 

Pb(NO₃)₂ is the limiting reactant 

Q7)
then the amount of PbI₂ formed depends on amount of Pb(NO₃)₂ present 
therefore number of moles of PbI₂ formed is based on number of Pb(NO₃)₂ moles present 
as calculated in Question number 4 - Q4
number of PbI₂ moles formed - 0.00181 mol 
mass of PbI₂ formed - 461 g/mol x 0.00181 mol = 0.834 g
mass of PbI₂ formed - 0.834 g

Q8) 
actual yield obtained  is not always equal to the theoretical yield . therefore we have to find the percent yield. This tells us the percentage of the theoretical yield that is actually obtained after the experiment
percent yield = actual yield / theoretical yield x 100 %
percent yield = 0.475 g / 0.834 g x 100 % = 57.0 %
percent yield of lead iodide is 57.0 %

Equilibrium is established in a reversible reaction when:

a) the [product] = [reactants]

b) rate of reaction of products = rate of reaction of reactants

c) all the reactants dissolve or dissociate

d) when product are no longer produced

Answers

Final answer:

Equilibrium in a reversible reaction is established when the rate of the forward reaction (reactants transforming into products) equals the rate of the backward reaction (products reconverting into reactants). This indicates that the amounts of products and reactants are no longer changing over time.

Explanation:

In a reversible reaction, equilibrium is established when option (b) is correct: the rate of the forward reaction (reactants transforming into products) becomes equal to the rate of the backward (or reverse) reaction (products converting back into reactants). This does not necessarily mean the concentrations of the products and reactants are equal. Rather, it means the amounts of products and reactants are no longer changing over time, demonstrating a state of dynamic equilibrium. The equilibrium can shift depending on external factors and conditions such as temperature, pressure, or concentration changes, which is described by Le Chatelier's Principle.

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What is the value of δg°' (or, to put it another way, the cost) when 2nadp+ and 2h2o are converted to 2nadph plus 2h+ plus o2?

Answers

the answer is 104.9, i dont know how though

The chemical reaction is given as:

[tex]2NaDP^{+} +2H_{2}O\rightarrow 2NaDPH+2H^{+}+O_{2}[/tex]

Here, oxygen is oxidised and [tex]NaDP^{+}[/tex] is reduced. Thus, redox reaction occurs.

For cell reaction, [tex]\Delta G^{o} = -nFE^{o}_{cell}[/tex]          (2)

where, [tex]\Delta G^{o} [/tex] = standard state free energy

n= number of electrons

F= Faraday constant ([tex]96485.33 C/mol[/tex])

[tex]E^{o}_{cell}[/tex] = cell potential

Substitute the value of number of electrons i.e. 2, Faraday constant and cell potential in the formula to determine the value of  [tex]\Delta G^{o} [/tex].

Now, calculate the value of cell potential

[tex]E^{o}_{cell} = E^{o}_{cathode}- E^{o}_{anode}[/tex]           (1)

[tex]E^{o}_{cathode}[/tex] = [tex]-0.324 V[/tex] (standard reduction potential of [tex]NaDP^{+}[/tex])

[tex]E^{o}_{anode}[/tex] = [tex]1.23 V[/tex] (standard reduction potential of [tex]O_{2}[/tex])

Put the above values in formula (1), we get:

[tex]E^{o}_{cell} = -0.324 V-1.23 V[/tex]

= [tex]-1.554 V[/tex]

Now, substitute above value in formula (2)

[tex]\Delta G^{o} = -2\times 96485.33 C/mol \times(-1.554 V) [/tex]  

= [tex]299876.40564 CV/mol[/tex]

Since, one coulomb volt is equal to one joule.

Thus, value of [tex]\Delta G^{o}[/tex] is equal to [tex]299876.40564 J/mol[/tex] or [tex]299.87640564 kJ/mol[/tex]








Draw any one of the skeletal structures of a 2° alkyl bromide having the molecular formula of c6h13br and two stereogenic centers. indicate chirality by using wedge and hashed wedge notation. lone pairs do not need to be shown.

Answers

Check the following picture: 

The  skeletal structures of a 2° alkyl bromide with two  stereogenic centers is shown below.

What are the stereogenic centers in 2° alkyl bromide ?

A carbon atom in a molecule that is linked to four separate substituents is referred to as a stereogenic center, also referred to as a chiral center. Because secondary carbon atoms normally have two identical alkyl groups and two hydrogen atoms linked to them.

The two of the substituents (two alkyl groups) are the same. Tetrahedral carbon compounds with four distinct substituents are frequently where chirality occurs.

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1. Which of the following statements about mechanical waves is true?
a. mechanical waves require a medium to travel through
b. mechanical waves do not have amplitude and wavelength
c. mechanical waves do not have frequency
d. mechanical waves can travel through blank space

2. Which waves have the shortest wavelength and highest energy on electromagnetic spectrum?
a. microwaves
b. x-rays
c. infrared
c. gamma rays

3. What is true about infrared and X-Rays?
a. X-Rays have greater longer wavelength than infrared
b. Infrared have shorter wavelength than x-rays
c. x-rays have lower energy than infrared
d. Infrared have lower frequency than x-rays

4. In a longitudinal wave (compression wave_ the particles of a matter move ______
a. perpendicular (at right angles)
b. in a circular direction
c. backwards
d. parallel

5. In regard to spend of sound, sound travels slowest in ____
a. solids
b.liquids
c. gases

Answers

1. The answer is "a".


Mechanical waves require a medium to travel. If there is no medium, the mechanical wave doesn't travel. Since, they are waves; they have a wavelength, frequency, speed and also amplitude. The speed depends on the medium and type of the wave. An example for the mechanical waves is sound wave.


2. E = hf, where E is energy, h is plank constant and f is the frequency. Hence, if the frequency is high, then the energy is high. 


v = fλ , where v is the speed, f is the frequency and λ is the wavelength. If the frequency is high, then the wavelength is low.


According to the given choices, gamma rays have the shortest wavelength and highest energy on electromagnetic spectrum.


3. The wavelength of X-rays are smaller the wavelength of infrared.

According to the v=fλ, lower the wavelength, then higher the frequency.  According to the E = hf, if the frequency is high, then the energy is also high. 


Hence, the correct answer is "d"


4. In a longitudinal wave (compression wave) the particles of a matter move parallel


There are two types of waves according to the particle movement. They are transverse waves and longitudinal waves. In transverse waves, the particles of the medium move perpendicular to the direction of the wave and longitudinal waves have parallel movement of particles to the direction of wave.


5. In regard to spend of sound, sound travels slowest in gases.

 

Solids have the highest speed of sound while gases have the lowest. This is because of the particle arrangement of each phase. Solid phase has very tightly packed particle arrangement and due to that the transfer of sound wave in easy than in gases.

A solution is prepared by condensing 4.00 l of a gas, measured at 27°c and 748 mmhg pressure, into 58.0 g of benzene. calculate the freezing point of this solution. [kfp(benzene) = 5.12°c/m, kbp(benzene) = 2.53°c/m] (the boiling point and freezing point of benzene are 80.1°c and 5.5°c, respectively).

Answers

First, we are using the ideal gas law to get n the number of moles:

PV = nRT

when P is the pressure = 748 mmHg/760 = 0.984 atm

V is the volume = 4 L

R is ideal gas constant = 0.0821

T is the temperature in Kelvin = 300 K

∴ n =  0.984atm*4L/0.0821*300

       = 0.1598 moles

when the concentration = moles * (1000g / mass)

                                         = 0.1598 * (1000g / 58 g )

                                         = 2.755 M

when the freezing point = 5.5 °C

and Kf = - 5.12 °C/m

∴ the freezing point for the solution = 5.5 °C + (Kf*m)

                                                            = 5.5 °C - (5.12°C/m * 2.755m)

                                                            = -8.6 °C

The new freezing point of the solution is -8.63 °C.

Using the ideal gas law, PV = nRT, we need to convert 4.00 L of gas at 27°C (which is 300 K) and 748 mmHg to moles of gas.

P = 748 mmHg / 760 mmHg atm = 0.984 atm

[tex]n = \frac{PV}{RT} = \frac{0.984 \, \text{atm} \times 4.00 \, \text{L}}{0.0821 \, \text{L atm / K mol} \times 300 \, \text{K}} = 0.160 \, \text{mol}[/tex]

Calculate molality:

Molality (m) = moles of solute / kg of solvent = 0.160 mol / 0.0580 kg = 2.759 m

Calculate freezing point depression (ΔTf):

ΔTf = i * Kf * m

For non-electrolytes, i = 1.

ΔTf = 1 * 5.12 °C/m * 2.759 m = 14.13 °C

Determine the new freezing point:

The freezing point of pure benzene is 5.5 °C.

New freezing point = 5.5 °C - 14.13 °C = -8.63 °C

Thus, the freezing point of the solution is -8.63 °C.

A sample of he gas (2.35 mol) occupies 57.9 l at 300.0 k and 1.00 atm. the volume of this sample is _____ l at 423 k and 1.00 atm.

Answers

The  volume  of  the sample  at 423 k  and 1.00 atm  is calculated using  Charles  law  formula   that is V1/T1 =V2/T2 since  the  pressure is  constant

V1=75.9  L
T1=  300 K
V2=?
T2=423 k

by   making the V2 the  subject  of  the formula

V2=T2V1/T1
V2=  57.9 L  x 423 K/300 K=  81.64 L  is the volume of the  sample

The ideal gas relates to the pressure, temperature, pressure, and mole of the gas. The volume of the sample at 423 K and 1 atm is 81.64L.

What is Charles's law?

Charles law gave the relation between the temperature and the volume of gas. According to him, the volume of the gas is directly proportional to the temperature of the gas.

Given,

Initial volume = 75.9 L

Initial temperature = 300 K

Final volume = ?

Final temperature = 423 K

The relation between the temperature and the volume of the two gases is shown as:

[tex]\rm \dfrac{V_{1}}{T_{1}} = \rm \dfrac{V_{2}}{T_{2}}[/tex]

Substituting values in the above equation:

[tex]\begin{aligned}\rm V_{2}& = \rm \dfrac{T_{2}V_{1}}{T_{1}}\\\\&= \dfrac{57.9\times 423}{300}\\\\&= 81.64 \;\rm L \end{aligned}[/tex]

Therefore, 81.64 L is the final volume at 423 K.

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A strontium-90 atom that has lost 2 electrons has ________ protons, ________ neutrons, and ________ electrons.

Answers

For an atom, the atomic number is equal to number of protons and number of electrons. Mass number is sum of number of protons and neutrons in nucleus of an atom. Atomic number is denoted by symbol Z and mass number is denoted by symbol A.

The atomic number of strontium is Z=38 and mass number is A=90.

Now, [tex]Z=n_{p}=n_{e}=38[/tex]

Also, [tex]A=n_{p}+n_{n}=90[/tex]

Putting the value of [tex]n_{p}[/tex] in above equation,

[tex]A=38+n_{n}=90[/tex]

Or,

[tex]n_{n}=90-38=52[/tex]

Thus, number of neutrons are 52.

Now, after losing two electrons, number of protons and neutrons remains the same but number of electrons becomes 38-2=36

Therefore, a strontium-90 atom that has lost 2 electrons has 38 protons, 52 neutrons and 36 electrons.

Final answer:

A strontium-90 atom that has lost two electrons has 38 protons, 52 neutrons, and 36 electrons.

Explanation:

A strontium-90 atom originally has 38 protons, 52 neutrons, and 38 electrons. If it has lost 2 electrons, then it has 36 electrons left. So, a strontium-90 atom that has lost 2 electrons has 38 protons, 52 neutrons, and 36 electrons. The atomic number of strontium is 38, which tells us its number of protons, and by subtracting this number from the atomic mass, we get the number of neutrons. The number of electrons in a neutral atom should be equal to the number of protons, but if the atom becomes an ion and loses electrons in the process, the number of electrons decreases.

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What is the volume of 0.250 m hydrochloric acid required to react completely with 20.0 ml of 0.250 m ca(oh)2?

Answers

the balanced equation for the above neutralisation reaction is as follows;
Ca(OH)₂ + 2HCl ----> CaCl₂ + 2H₂O
Stoichiometry of Ca(OH)₂ to HCl is 1:2
number of Ca(OH)₂ moles reacted - 0.250 mol/L x 20.0 x 10⁻³ L = 5.00 x 10⁻³ mol
according to molar ratio of 1:2
number of HCl moles required = 2 x number of Ca(OH)₂ moles reacted
number of HCl moles = 5.00 x 10⁻³ x 2 = 10.0 x 10⁻³ mol
molarity of HCl solution - 0.250 M
there are 0.250 mol  in volume of 1 L
therefore 10.0 x 10⁻³ mol in - 10.0 x 10⁻³ mol  / 0.250 mol/L = 40.0 mL 
40.0 mL of 0.250 M HCl is required

How much 0.100 m hcl is required to completely neutralize 20.0 ml of 0.250 m naoh?

Answers

the balanced equation for the reaction between NaOH and HCl is as follows
NaOH + HCl ---> NaCl + H₂O
stoichiometry of NaOH to HCl is 1:1
number of NaOH moles reacted - 0.250 mol/L x 0.0200 L = 0.005 mol 
therefore number of HCl moles reacted - 0.005 mol 
molarity of given HCl solution - 0.100 M
number of HCl moles in 1 L - 0.100 mol 
then 0.005 mol of HCl in - 0.005 mol / 0.100 mol/L = 50.0 mL
volume of HCl required is 50.0 mL
Final answer:

To neutralize 20.0 mL of 0.250 M NaOH, you will need 50.0 mL of 0.100 M HCl.

Explanation:

To determine how much 0.100 M HCl is required to neutralize 20.0 mL of 0.250 M NaOH, we can use the balanced equation for the reaction between HCl and NaOH: HCl(aq) + NaOH(aq) → H2O(l) + NaCl(aq). The mole ratio between HCl and NaOH is 1:1, meaning that 1 mole of HCl reacts with 1 mole of NaOH. We can use this ratio to calculate the amount of HCl needed.

First, find the number of moles of NaOH:

0.250 M NaOH x 0.0200 L = 0.005 moles NaOH

Since the mole ratio between HCl and NaOH is 1:1, we need 0.005 moles of HCl to neutralize the NaOH.

Now, calculate the volume of 0.100 M HCl needed to contain 0.005 moles:

0.005 mol HCl / 0.100 mol/L = 0.050 L = 50.0 mL

Therefore, 50.0 mL of 0.100 M HCl is required to completely neutralize 20.0 mL of 0.250 M NaOH.

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N aqueous solution of sodium hydroxide is standardized by titration with a 0.154 m solution of hydrochloric acid. if 17.5 ml of base are required to neutralize 17.6 ml of the acid, what is the molarity of the sodium hydroxide solution?

Answers

the balanced equation for the above reaction is as follows;
NaOH + HCl --> NaCl + H₂O
stoichiometry of NaOH to HCl is 1:1
Number of HCl moles reacted - 0.154 mol/L x 0.0176 L = 0.00271 mol
the number of NaOH moles reacted = number of HCl moles reacted
number of NaOH moles reacted - 0.00271 mol 
number of NaOH moles in 17.5 mL - 0.00271 mol 
therefore NaOH moles in 1000 mL - 0.00271 mol / 17.5 mL x 1000 mL 
molarity of NaOH - 0.155 M

If 2.00 g of mg reacts completely with 50.0 ml of hcl solution, what is the molarity of the hcl solution? mg(s) + 2hcl(aq) → mgcl2(aq) + h2(g)

Answers

The molarity of HCl is calculated as below

find the moles  of   mg used
moles = mass /molar mass

= 2.00g/24 g/mol=0.083 moles
 write the  reacting equation
Mg(s) +2HCl (aq)= MgCl2(aq) + H2(g)

by use of mole ratio between Mg to HCl  which is 1  :2 the moles of HCl is therefore
= 0.083 x2 =0.166 moles

molarity of HCl = moles of HCl/ volume in dm^3

that is 0.166/50 x1000= 3.3 M of HCl
the balanced equation for the reaction between Mg and HCl is as follows;
Mg + 2HCl ---> MgCl₂ + H₂
stoichiometry of Mg to HCl is 1:2
number of moles of Mg reacted - 2.00 x 10⁻³ g / 24 g/mol = 0.0833 x 10⁻³ mol 
according to molar ratio 
number of HCl moles reacted - 0.0833 x 10⁻³ x 2 mol = 0.167 x 10⁻³ mol 
number of HCl moles in 50.0 mL -  0.167 x 10⁻³ mol 
therefore number of HCl moles in 1000 mL -  0.167 x 10⁻³ mol / 0.0500 L 
molarity of HCl - 0.00334 M

Which statement best describes how activation energy influences a reaction?

Answers

The correct answer is:
The greater the activation energy, the lower the reaction rate.


Activation energy simply means the minimum amount of energy needed for the particles to have a successful reaction when they collide. There are two basic factors necessary for a reaction to just take place.

Particles need to collide with each other with minimum amount of energry.They must hit each other in proper orientation. If the particles are colliding each other at proper orientation but not with sufficient energy, then reaction will not take place. Higher activation energy means that more energy will be required for the particles to have a successful collision. Like, combustion. It is generally an exo reaction but still needs heat. It is because activation energy is high. Heat causes particles to gain enough energy to overcome the activation energy barrier. So basically, higher activation energy means slow rate and lower means higher rate

The value of ka for nitrous acid (hno2) at 25 ∘c is 4.5×10−4. what is the value of δg at 25 ∘c when [h+] = 5.9×10−2m , [no2-] = 6.3×10−4m , and [hno2] = 0.21m ? be sure to express your answer in units of kj in the box below. answers without units will not be given credit.

Answers

Final answer:

By applying the modified Gibbs Free Energy formula with given values for equilibrium constants, atom concentrations, and other parameters, we find ΔG for nitrous acid at 25°C to be around 27.94 KJ/mol.

Explanation:

In chemistry, the Gibbs free energy (ΔG) is calculated using the equation ΔG = -RTlnK, where R is the gas constant, T is the temperature in Kelvin, and K is the equilibrium constant. However, since we're given Ka, the equation must be adapted. Therefore, we use ΔG = -RTlnKa + RTlnQ, where Q is the reaction quotient given by [NO₂⁻][H⁺] / [HNO₂].

Inserting the given values, such as Ka = 4.5×10⁻⁴, R (in appropriate units) as 0.0083145 KJ/(mol.K), T as 298.15K (25°C in Kelvin), and Q = ([NO₂⁻][H⁺]) / [HNO₂] = (6.3×10⁻⁴ × 5.9×10−2) / 0.21, we can now solve for ΔG. Doing the math, we find that ΔG ≈ 27.94 KJ/mol.

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What is the average kinetic energy kavg of the hydrogen molecules at a temperature of 100k? assume that the molecules have only three degrees of freedom at this temperature?

Answers

The average kinetic energy of hydrogen molecules at 100 K with three degrees of freedom can be calculated using the formula kavg = 3/2 * k * T, where k is Boltzmann's constant and T is the temperature in Kelvin.

The average kinetic energy kavg of hydrogen molecules at a temperature of 100 K with three degrees of freedom can be calculated using the formula:

kavg = 3/2 * k * T

where k is Boltzmann's constant (1.38 x 10^-23 J/K) and T is the temperature in Kelvin. Plugging in the values:

kavg = 3/2 * 1.38 x [tex]10^{-23}[/tex] J/K * 100 Kkavg = 2.07 x [tex]10^{-21}[/tex] J

In general, metals react by:

A. gaining valence electrons
B. sharing valence electrons
C. sometimes gaining and sometimes losing valence electrons
D. losing valence electrons

Answers

Hello there,
The answer is D. Losing Valence electrons.

Hope this helped and if you have any more questions please feel free to ask me.
Have a nice day!

Answer: Option (D) is the correct answer.

Explanation:

It is known that metals are the substances which hold excess number of electrons and hence they need to lose electrons in order to gain stability.

For example, potassium is a metal with atomic number 19 and its electronic configuration is 2, 8, 8, 1.

So, it needs to gain stability and hence, it easily loses its one valence  electron to acquire a positive charge as [tex]K^{+}[/tex].

Thus, we can conclude that in general, metals react by losing valence electrons.


Given the balanced ionic equation representing a reaction:



In this reaction, electrons are transferred from


A)
Al to Mg2+

B)
Al3+ to Mg

C)
Mg to Al3+

D)
Mg 2+ to Al

pls explain

Answers

2Al³⁺ (aq) + 3 Mg⁰ (s) --> 3Mg²⁺ (aq) + 2Al⁰ (s)

Al³⁺  +3e⁻ ------> Al⁰ 
Al had positive charge and them it became neutral, that means that it took 3 negative particles (electrons).    (+3-3=0)
We have 2 Al³⁺, and they take 3*2 =6 electrons

Mg⁰  -----> Mg²⁺ + 2e⁻
Mg was neutral atom, and them it became positive ion, that means it lost electrons .  (0=+2-2)
We have 3Mg, and they loose 2*3=6 electrons.

Mg loose electrons, Al³⁺ takes electrons, that means that electrons are transferred from  Mg to Al³⁺.

Answer is C).

How many atoms are in 1.00 gram of Ag? Express your answer in scientific notation. _____× 10^___ atoms

Answers

 The  number  of atoms in 1.00 grams  of Ag  is calculated as  below

calculate  the moles of Ag = mass/molar mass

=  1g/ 107.87 g/mol= 9.27 x10 ^-3  moles

by use  of Avogadro law  constant 1 mole = 6.02 x10^23 atoms

what  about 9.27 x10 ^-3  moles

= (9.27 x10^-3 moles/ 1mole) x6.02 x10 ^23  atoms  = 5.581  x10^ 21 atoms

Given the reaction: cu(s) + 4hno3(aq) → cu(no3)2(aq) + 2no3(g) + 2h2o(l )as the reaction occurs, what happens to copper?

Answers

When copper reacts with nitric acid, then cooper nitrate, water, and nitrogen dioxide are produced. In this reaction, copper gets oxidized by nitric acid.

What is oxidation?

Oxidation is a type of chemical reaction involving the sharing of electrons and an increase or decrease of the oxidation number. When a chemical species loses an electron, it is said to be oxidized.

The balanced chemical reaction is given as:

Cu(s) + 4HNO₃(aq) → Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)

In the reaction, copper forms copper nitrate, and its oxidation changes from 0 to +2. On the other hand, nitrate species get reduced to nitrogen dioxide and change the state from +5 to +4.

Therefore, copper gets oxidized by nitric acid.

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When heated, calcium carbonate decomposes to yield calcium oxide and carbon dioxide gas via the reaction caco3(s)→cao(s)+co2(g) what is the mass of calcium carbonate needed to produce 61.0 l of carbon dioxide at stp? express your answer with the appropriate units?

Answers

Answer is: 227.3 grams of of calcium carbonate needed.
Chemical reaction: CaCO₃ → CaO + CO₂.
V(CO₂) = 61.0 L.
n(CO₂) = V(CO₂) ÷ Vm.
n(CO₂) = 61 L ÷ 22.4 L/mol.
n(CO₂) = 2.723 mol.
From chemical reaction: n(CO₂) : n(CaCO₃) = 1 : 1.
n(CaCO₃) = 2.273 mol.
m(CaCO₃) = n(CaCO₃) · M(CaCO₃).
m(CaCO₃) = 2.273 mol · 100 g/mol.
m(CaCO₃) = 227.3 g.

For producing 61 L of [tex]\rm CO_2[/tex], 227.23 grams of  [tex]\rm CaCO_3[/tex]. is required.

Any gas occupies 22.4 L/mol space at STP.

So, 61.0 L of gas will be;

Moles of [tex]\rm CO_2[/tex] = [tex]\rm \frac{61.0}{22.4}[/tex]

Moles of  [tex]\rm CO_2[/tex] = 2.723 moles

From the reaction,

1 mole of [tex]\rm CO_2[/tex] has been produced by 1 mole of [tex]\rm CaCO_3[/tex].

2.723 moles of [tex]\rm CO_2[/tex] has been produced by 2.723 mole of [tex]\rm CaCO_3[/tex].

Mass = [tex]\rm moles\;\times\;molecular\;weight[/tex]

Mass of [tex]\rm CaCO_3[/tex]. = 2.723 [tex]\times[/tex] 100

Mass of [tex]\rm CaCO_3[/tex]. = 227.23 grams.

For producing 61 L of [tex]\rm CO_2[/tex], 227.23 grams of  [tex]\rm CaCO_3[/tex]. is required.

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Which of the two substances would have the higher boiling point ch4 or c?

Answers

ch4 boiling point: -258.7 F (-161.5 C)
c boiling point: 8,721 F (4,827 C)

therefore: carbon has a higher boiling point

ch4 is also a gas at room temp which is why it’s boiling point is so low.
c is a solid at room temp

Carbon has a higher boiling point than [tex]CH_4[/tex].

What is Boiling Point?

The boiling point of a substance is defined as the temperature at which the vapor pressure of the liquid becomes equal to the pressure surrounding the liquid and the liquid changes into vapor. This point of liquid varies depending on the surrounding environmental pressure.

The boiling point is the temperature at which the pressure exerted by the surroundings on a liquid is equal to the pressure exerted by the liquid's vapor, in which case the liquid changes to vapor without additional heat raising the temperature.

For above given example,

[tex]CH_4[/tex] is a gas at room temperature having a boiling point of -258.7 F (-161.5 C) which is why it’s boiling point is so low while Carbon is a solid at room temperature having a boiling point of 8,721 F (4,827 C)

Thus, Carbon has a higher boiling point than [tex]CH_4[/tex].

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Which of the following phase changes would release energy as it occurs? (4 points) Melting
Boiling
Evaporating
Freezing

Answers

I believe it is freezing.

Use appropriate data to calculate δg∘ for the reaction. 2mno−4(aq)+cd(s)→2mno2−4(aq)+cd2+(aq) express your answer to three significant figures and include the appropriate units.

Answers

Reaction at anode: Cd    →     Cd2+    +     2e-, Eo = -0.403 v
Reaction at cathode:     2MnO4-   +    2e-     →      MnO4^2-, Eo = 1.5 v

Net reaction: Cd  +   2MnO4-    ⇆     Cd2+     +     MnO4^2-

Net cell representation: Cd/Cd2+// MnO4-/MnO4^2-

Now, standard EMF of cell = E(o)cell = Er - El
                                                            = 1.5 - (-0.403)
                                                            = 1.903 v

Now, ΔGo = -nFE(o)cell
where n = number of electrons = 2
F = faraday's constant = 96500

ΔGo = - 2 X 96500 X 1.903
         = 367.27 kJ

Answer:

∆G° = -185 kJ

Explanation:

First, use the half-reaction method:

OX: Cd ⟶ Cd2+ + 2e- where E° = -0.40 V (anode)

RED: 2MnO-4 + e- ⟶ 2MnO2-4 where E° = 0.56 V (cathode)

Balance the chemical equation with the correct stoichiometric coefficients:

2 × (2MnO-4 + e- ⟶ 2MnO2-4) = 4MnO-4 + 2e- ⟶ 4MnO2-4

1 × (Cd ⟶ Cd2+ + 2e-) = Cd ⟶ Cd2+ + 2e-

Cancel out e- on both sides to get:

4MnO-4 + Cd ⟶ 4MnO2-4 + Cd2+

Using this balanced equation, we can determine:

number of moles of electrons exchanged in the cell reaction, n = 2

E°cell = E°cathode - E°anode = 0.56 - (-0.40) = 0.96 V

F, Faraday's constant: 96485 / mol e-

∆G° = -nFE°cell = -(2)(96485)(0.96)

∆G° = -185251.2 J = -185 kJ

What is the percent of MgSO4 in magnesium sulfate heptahydrate?
48.83 %
51.17 %
95.43 %
86.98 %

Answers


one mole of MgSO4.7H2O weighs 246.4696 g 

in that one mole are seven moles of H2O, weighing 126.1036 g 

The percentage of water is this calculation: 

(126.1036 / 246.4696) * 100 = 51.17%

Determine the overall charge on each complex tetraquadichlorochromium (iii)

Answers

Answer:
             +1

Explanation:
                   Molecular Formula of Tetraquadichlorochromium (III) is as follow,

                                               [Cr(H₂O)₄Cl₂]ˣ

The oxidation states of elements present in complex are,

                                  H₂O  =  0     (Neutral Ligand)

                                  Cl  =  -1

                                  Cr  =  +3      (Given)

                                  x  =  Overall charge
So,
                                 [+3 + (0)₄ + (-1)₂]  =  x

                                 [+3 - 2]  =  x

                                          x  =  +1

Result:
            
Overall charge on Tetraquadichlorochromium (III) is +1.

When the pressure that a gas exerts on a sealed container changes from 22.5 psi to ? psi, the temperature changes from 110 degrees celcius to 65.0 degrees celcius?

Answers

Using Gay-Lussac's Law, pressure is proportional to (absolute) temperature in Kelvin. We first convert the temperature values to Kelvin: 110 C = 383.15 K, while 65 C = 338.15 K.
P1/T1 = P2/T2
22.5/383.15 = P2/338.15
P2 = 19.9 psi

Answer:19.9

Explanation: make sure correct significant figures with psi

Identify the lowest energy lewis structure for nitrogen oxide

Answers

Below attachment shows the four possible lewis structures of Nitrogen Oxide (Nitrous Oxide).

Answer:
            Among given Lewis structures, Structure-C has the lowest energy.

Explanation:
                   The greater the stability of any compound the lesser will be its energy. Among different Lewis structures of N₂O or any other compound, the one which comprises of less number of formal charges will be having lesser energy. I have selected structure-C but not Structure-B (as both have same number of formal charges) because in structure-C oxygen has a formal charge of -1. Being more electronegative oxygen tends to attract electrons toward itself. While, in structure-B one of the Nitrogen atom is having -1 charge which is not feasible and makes the structure energetically high.
Final answer:

The lowest energy Lewis structure for nitrogen oxide (NO) involves one nitrogen and one oxygen atom sharing a total of 11 valence electrons with an unpaired electron on Nitrogen. It's an odd-electron molecule with a resonance structure, where the electron distribution is a hybrid average of a single and double bond.

Explanation:

The lowest energy Lewis structure for nitrogen oxide (NO) has one nitrogen atom and one oxygen atom with a total of 11 valence electrons. One of these electrons will remain unpaired, which is typical of chemicals that contain nitrogen. Therefore, the nitrogen has a single unpaired electron, while the oxygen atom is fully paired with two lone pairs and one shared pair.

Nitrogen oxide is an odd-electron molecule, meaning it has an unpaired electron which contributes to its reactive properties. Drawing a correct Lewis structure for such molecules involves the same steps as for other molecules, but there may be some unpaired electrons.

To summarize, nitrogen oxide (NO) has a resonance structure rather than a single Lewis structure, due to the presence of an unpaired electron. The representation of its electron distribution is an average of a single bond and a double bond, illustrated as a resonance hybrid of the individual resonance forms.

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How can erosion form new land? (site 2)

Answers

Erosion is essentially the removal of material by a natural force, most commonly this is water or air. This is how new landmass is formed from erosion. The material is just being moved then deposited in a new place. These new pieces of land are called depositional landforms.

Answer:

The procedure by which soil, land, or rock get slowly worn away by the natural elements like wind or water is known as erosion. The landforms refer to the natural characteristics found on the surface of the Earth that exhibit different shape and origin. The landforms can be destroyed and created by erosion.  

The landforms created by the process of erosion are known as fluvial erosion landforms. With the passing of water across the land, the sediments and other kinds of natural debris also get carried with it. With time, the gathering of the debris and sediments generate deposits that ultimately turn into a landform. Some of the examples of fluvial erosion landforms comprise flood plains, sandbars, and levees.  

Which is a major factor affecting population growth rate?

Answers

The population of the planet is constantly increasing, and this growth can have many effects on the environment and the economy of the world. For example, as the world population rises, the pressure mounts on the agricultural sector to feed the millions of extra mouths. In predicting the rise of the world population, scientists use a number of variables.


Fertility Rate

The factor which affects the growth of the population in the biggest way is the fertility rate. The fertility rate is typically measured by the number of children per one woman of child-bearing age. If the fertility rate is larger than 2, the rule of thumb is that the population should rise, as there are more children than their parents. On the other hand, if this ratio is below 2, the population of the region may be destined for a decline.

Mortality Rate

A key factor affecting the growth of the population is the death, or mortality, rate. Just as the birth of new people increases the population size, deaths decrease it. The factors that affect the mortality rate include the availability and affordability of quality health care and lifestyle habits – for example, whether they smoke or do physical exercises regularly.


Immigration and Emigration

Cross-border migration is the act of people moving from one country to another. It affects the population size of both the host and destination countries. Emigration is caused by a number of factors, such as fleeing war, finding education, seeking new jobs or joining family members. When a person emigrates from a country, its population shrinks. When someone moves to a country from another place, it is known as immigration. Whether or not a person is allowed to immigrate is controlled by the country that will host this person.

Government Restrictions

There are some people in the world, including politicians, who believe that some countries need to have a birth rate restriction -- in fact, China already has its widely-known one-child policy. Such a restriction would prevent couples from being able to have more than the restricted amount of children. The argument goes that this type of restriction would cause fewer resources to be used and prevent overpopulation.

Final answer:

Population growth rate is affected by several factors, including the birth and death rates, life expectancy, and the age structure of the population. Other factors include human migration and improvements in public health and sanitation.

Explanation:

A major factor affecting population growth rate is the birth and death rates. When birth rates exceed death rates, population size increases. Conversely, when death rates exceed birth rates, population size decreases. Life expectancy also plays an important role. The length of time individuals remain in the population impacts local resources, reproduction, and the overall health of the population.

Another factor is related to the age structure of a population, which is the proportion of a population in different age classes. Rapid growth countries often have a pyramidal age structure, showing many young, reproductive-aged individuals. On the other hand, areas with slow growth or zero growth tend to have a greater proportion of older individuals.

Additionally, other factors affecting human population growth include migration and improvements in public health and sanitation. The development and use of antibiotics and vaccines have decreased the prevalence of infectious disease, allowing human population to grow.

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What are the boiling point and freezing point of a 3.47 m solution of naphthalene in benzene? (the boiling point and freezing point of benzene are 80.1°c and 5.5°c respectively. the boiling point elevation constant for benzene is 2.53°c/m, and the freezing point depression constant for benzene is 5.12°c/m.)?

Answers

Elevation in boiling point is mathematically expressed as
ΔTb = Kb X m

where Kb =  boiling point elevation constant =  2.53°c/m (for benzene)
m = molality of solution = 3.47 m (given)

∴ ΔTb = 2.53 X 3.47
           = 8.779 oC

But, boiling point of benzene = 80.1 oC
∴ Boiling point of solution = 88.879 oC

Now, Depression in freezing point = ΔTf = Kf X m
where, Kf = freezing point depression constant = 5.12°c/m (for benzene)

∴ ΔTf = 5.12 X 3.47
         = 17.766 oC

But freezing point of benzene = 5.5 oC
∴ Freezing point of solution = -12.266 oC

The study of chemicals and bonds is called chemistry. There are two types of elements and these are metals and nonmetals.

The correct answer is -12.266.

What is the boiling point?The boiling point of a liquid varies according to the applied pressure; the normal boiling point is the temperature at which the vapor pressure is equal to the standard sea-level atmospheric pressure (760 mm [29.92 inches] of mercury). At sea level, water boils at 100° C.

Elevation in boiling point is mathematically expressed as

[tex]Tb = Kb * m[/tex]

Where

Kb =  boiling point elevation constant =  2.53°c/m (for benzene)m = molality of solution = 3.47 m (given)

ΔTb[tex]= 2.53 * 3.47 = 8.779 oC[/tex]

But, the boiling point of benzene = 80.1 oC

Boiling point of solution = 88.879 oC

Now, Depression in freezing point = ΔTf[tex]= Kf * m[/tex]

where,

Kf = freezing point depression constant = 5.12°c/m (for benzene)

ΔTf =[tex]5.12 X*3.47 = 17.766 oC[/tex]

But the freezing point of benzene = 5.5 oC.

Freezing point of solution = -12.266 oC.

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