Answer:
Approximately [tex]-74.8\; \rm kJ \cdot mol^{-1}[/tex].
Explanation:
Number the three reactions with known enthalpy changes:
[tex]\begin{aligned}& {\rm C\; (s) + O_2\; (g) \to CO_2\; (g)} & \quad \Delta H = -393.5\; \rm kJ\cdot mol^{-1}& \quad (1) \\ & {\rm H_2\; (2) + \frac{1}{2} O_2\; (g) \to H_2O\; (l)} & \quad \Delta H = -285.8\; \rm kJ\cdot mol^{-1} & \quad (2) \\ & {\rm CH_4\; (g) + 2\; O_2\; (g) \to CO_2\; (g) + 2\; H_2O\; (l)} & \quad \Delta H = -890.3\; \rm kJ\cdot mol^{-1} & \quad (3)\end{aligned}[/tex].
The goal is to find a way to combine these three reactions to obtain: [tex]\rm C\; (s) + 2\; H_2\; (g) \to CH_4\; (g)[/tex].
Assume that the three known reactions are combined in this way:
[tex]a \times (1) + b \times (2) + c \times (3)[/tex].
That corresponds to:
[tex]\begin{aligned} & a\; \mathrm{C\; (s)} + \left(a + \frac{1}{2}\, b + c\right) \; \mathrm{O_2\; (g)} + b\; \mathrm{H_2\; (g)} + c\; \mathrm{CH_4\; (g)} \\ & \to (a + c)\; \mathrm{CO_2\; (g)} + (b+ 2\,c )\; \mathrm{H_2O\; (l)}\end{aligned}[/tex].
Compare the coefficients of this reaction with that of the desired reaction:
[tex]\rm C\; (s) + 2\; H_2\; (g) \to CH_4\; (g)[/tex].
Note that some species (e.g., [tex]\rm CH_4\; (g)[/tex]) appeared on the wrong side of the equation. Their desired coefficient should be the opposite of their true coefficient. For example, the coefficient of [tex]\rm CH_4\; (g)[/tex] is supposed to be [tex]1[/tex]. However, because it appeared on the wrong side of the equation, its desired coefficient would be [tex]-1[/tex].
The coefficients of species that are not in the desired equation should be zero.
[tex]\begin{array}{|c|c|c|}\cline{1-3}\text{Species} & \text{Coefficient}& \text{Desired Coefficient} \\ \cline{1-3} \mathrm{C\; (s)}} & a & 1 \\ \cline{1-3} \mathrm{O_2\; (g)} & a + (1/2)\, b + c & 0 \\ \cline{1-3} \mathrm{H_2\; (g)} & b & 2 \\ \cline{1-3}\mathrm{CH_4\; (g)} & c & -1\\ \cline{1-3} \mathrm{CO_2\; (g)} & a + c & 0 \\ \cline{1-3} \mathrm{H_2O\; (l)} & b + 2\, c & 0\\ \cline{1-3}\end{array}[/tex].
Solve for [tex]a[/tex], [tex]b[/tex], and [tex]c[/tex]:
[tex]a = 1[/tex].[tex]b = 2[/tex].[tex]c = -1[/tex]. In other words, the third equation is inverted before being added to the other two equations.In other words, the desired equation is equal to [tex]1 \times (1) + 2 \times (2) - 1 \times (3)[/tex].
By Hess's Law, the enthalpy of the desired equation will be:
[tex]\begin{aligned}& 1\times \Delta H (1) + 2 \times \Delta H (2) - 1\times \Delta H(3) \\ &\approx -393.5 + 2 * (-285.8) - (-890.3) \\ &= -74.8\; \rm kJ \cdot mol^{-1} \end{aligned}[/tex].
When a radioactive atom emits an alpha particle, the mass number of the radioactive atom
A. Increases because the alpha particle contains 2 electrons
B. Decreases because the alpha particle contains 2 electrons
C. Increases because the alpha particle contains 2 protons
D. Decreases because the alpha particle contains 2 protons
Answer:
d or c
Explanation:
Answer:
c
Explanation:
did it
identify as the following as an element or a compound. its not multiple choice a) NaCI b) AR d) 02 c) CH4 d) 02 e) CI
Answer:
A. compound (NaCl)
B. element (note: it should be Ar. AR is not an element or compound.)
c. compound (CH4)
d. element (O2)
e. element (Cl)
Explanation:
Element is single and by its self. A compound is multiple elements put together.
If the temperature of a gas decreases at constant volume which of the following would occur
Answer:
I need the things after "which of the following would occur".
Explanation:
If you were to maintain a constant volume while decreasing pressure, the temperature would also have to decrease. This is Boyle's law.
Relate dark matter to the development of the universe after the Big Bang. In 3-5 sentences, speculate on how the development of the universe would have been different if there had been no dark matter. In your answer, use the term structures.
Please answer if you do i will mark you as brainliest
Answer:
Without dark matter galaxies would loose an extreme amount of gas required to create stars.
Without dark matter the universe wont have as many galaxies clumped together forming larger versions of those galaxies. This would cause a change in the structure of the "skeleton" of the web.
(Hope this can help, I didn't do exactly as it is said to because that is your job)
:)
Explanation:
Forbes gives somewhat of an explanation if you are curious.
(Ethan Siegal, "The Universe Would Be Very Different Without Dark Matter", Forbes)
Dark matter makes up most of matter in the universe and is found by a quarter of the total composition of the space. After the event of the big bang, the universe expanded and dark matter grew.
Dark matter accounts for about 85% of the matter in the universe. Its presence can be felt in the gravitational effects. Dark matter doesn't interact with the electromagnetic field. After the big bang event, the dark matter still can be found in larger galaxies and contest about 26% of mass-energy and 69% of dark energy. If there had been no dark matter there would be no structure of the cosmic web of galaxies. That is there would be no connection between the galaxies and would remain in isolated fragments.Thus dark matter is a link within and with the comic web.
Learn more about the dark matter and its development-related after the big bang event
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How does the concentration of reactants affect the rate of a reaction?
A. Increasing the concentration increases the kinetic energy of the
molecules.
B. Increasing the concentration increases the molecules' collision
frequency
c. Increasing the concentration decreases the reaction's activation
energy
D. Increasing the concentration increases the temperature of the
solution
Answer: The amount of reactant doesn't really affect the rate of reaction, but the concentration does.
In order for there to be a reaction there has to be collisions between molecules, but only a fraction of these collisions are successful. The molecules have to be moving with enough energy, called the activation energy, to break the bonds between atoms. If there is a higher concentration of a solution, there are more molecules present per unit volume. This means that there will be more collisions and therefore more successful collisions, increasing the rate of reaction.
Explanation:
B
Answer: c
Explanation: im pretty sure its right im sorry if not
How many grams of iron(III) oxide would be required to make 187 g of iron
Answer:267 g
Explanation:
Answer:
267 g
Explanation:
In a nuclear reaction, which of the following must be conserved?
A. energy
B. mass
C. charge
D. the number of electrons
Answer:
A. Energy must be conserved in a nuclear reaction
Explanation:
Answer:
Explanation:
In a nuclear reaction, which of the following must be conserved?
A. Energy
Can somebody please help me with these ? how many moles of AI are needed to react with 6 moles of O2?
Answer:
idkidkdkdkkdkdkdkddk
beudud
Explanation:
lolwoeo3i3iieieiekeididdo
What Le Chatelier’s factors cause an increase in the concentration of Hb(CO)4(aq) in the Hb(CO)4(aq) + 4O2(g)Hb(O2)4(aq) + 4CO(g)
Answer:
Explanation:
Hb(CO)4(aq) + 4O2(g) ⇄ Hb(O2)4(aq) + 4CO(g)
1 ) If we increase the concentration of CO(g) , the reaction above will proceed in reverse direction to decrease its concentration, according to Le Chatelier principle. Hence more of Hb(CO)4(aq) will be formed.
2 ) If we decrease the concentration of O₂ , then also , reaction will proceed in reverse direction . Hence concentration of Hb(CO)4(aq) will be increased .
An object becomes positively charged when it
a loses electrons.
b loses protons.
c gains electrons.
d gains neutrons.
Identifying Ways Rocks Change in the Rock Cycle Cycle of a rock. Arrows point from one stage to the next. Stage A, small, brown granules, to Compaction and cementation or Stage C. Arrow labeled Heat and pressure from Stage C to B, larger gray rocks. Arrow labeled Melting from Stage B to Magma. Arrow labeled Cooling from Magma to Igneous Rock. Arrow labeled Melting from Igneous Rock to Magma. Stage D arrows from Igneous Rock to Stage A, from Stage B to A, and from Stage C to A. Using the drop-down menus, label the parts of the rock cycle.
A- sediment, sedimentary rock, or metamorphic rock
B- sediment, sedimentary rock, or metamorphic rock
C- sediment, sedimentary rock or metamorphic rock
D- compaction and cementation, heat and pressure, or weathering and erosion
Answer:
sediment, metamorphic rock, sedimentary rock, weathering and erosion
Explanation:
for edge 2020
hope this helps
HAVE A GREAT DAY : )
Sediment, sedimentary rock, or metamorphic rock are the parts of the rock cycle. Therefore, the correct option is option A.
What are sedimentary rock, and metamorphic rock?Sedimentary rocks are created by the aggregation or deposition of organic or mineral particles at the Earth's surface, following by cementation. Sedimentation refers to the mechanisms that lead these grains to settle in situ.
Any of a family of rocks formed by the modification of pre - existing rocks in reaction to changing environmental circumstances, such as temperature, pressure, or mechanical stress, as well as the addition or deletion of chemical components is metamorphic rock. Sediment, sedimentary rock, or metamorphic rock are the parts of the rock cycle.
Therefore, the correct option is option A.
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How does activation energy affect the progress of a reaction?
O A. The reaction will not occur unless the activation energy is met.
B. The activation energy decreases the energy needed for a reaction
to progress.
C. The activation energy increases how quickly the reaction will
progress.
D. The activation energy determines equilibrium concentrations of
products.
Answer:
The reaction will not occur unless the activation energy is met.
Explanation
Answer:
A. The reaction will not occur unless the activation energy is met.
Explanation:
a.p.e.x
Which formula represents an alkane?
1.
C2H2
2.
C2H4
3.
C3H4
4.
С3Н8
Answer: Option 4) is correct.
Explanation: It is correct because alkanes have a general formula CnH2n+2. So, all we need to do is substitute and find out how many hydrogens are needed to make the formula an alkane. I am not really good at explaining. I am sorry If I confused you.
Alkanes are the organic compound which has general formula [tex]C_{n}H_{2n +2}[/tex] which satisfies the formula [tex]C_{3}H_{8}[/tex]. Hence [tex]C_{3}H_{8}[/tex] represents an alkane.
AlkaneAlkanes are simplest saturated hydrocarbon. Alkanes are also known as paraffins wax. Alkanes which contains only carbon and hydrogen atoms.
General Formula of AlkaneThe general formula of alkane is [tex]C_{n} H_{2n + 2}[/tex] where n = 1, 2, 3, 4.......
Consider Option 1, [tex]C_{2}H_{2}[/tex] here n = 2 now put the value of n in above formula, we get: [tex]C_{2} H_{2 \times 2 + 2}[/tex] = [tex]C_{2} H_{4 + 2}[/tex] = [tex]C_{2} H_{6}[/tex] , so option 1 does not satisfies the above formula. Hence it is incorrect. Consider Option 2, [tex]C_{2} H_{4}[/tex] here n = 2 now put the value of n in above formula, we get: [tex]C_{2} H_{2 \times 2 + 2} = C_{2} H_{4 + 2} = C_{2} H_{6}[/tex], so option 2 does not satisfies the above formula. Hence it is incorrect. Consider Option 3, [tex]C_{3} H_{4}[/tex] here n = 3 now put the value of n in above formula, we get: [tex]C_{3} H_{2 \times 3 + 2} = C_{3} H_{6 + 2} = C_{3} H_{8}[/tex], so option 3 does not satisfies the above formula. Hence it is incorrect. Consider Option 4, [tex]C_{3} H_{8}[/tex] here n = 3 now put the value of n in above formula, we get: [tex]C_{3} H_{2 \times 3 + 2} = C_{3} H_{6 + 2} = C_{3} H_{8}[/tex], so option 4 satisfies the above formula. Hence it is correct.Thus, from the above conclusion we can see that option 4 [tex]C_{3}H_{8}[/tex] represents an alkane.
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I just need the answer please to both if you can
Answer:
No.4 is B No.5 is d
Explanation:
Answer:
Q 4: d
Explanation: this is all I can answer
What is the specific heat capacity for a 5 g sample of metal that absorbs
100 Joules of heat energy when its temperature changes from 10 degrees
C to 40 degrees C?*
A) 15, 000 J/gC
B) 2 J/go
C)0.67 J/gC
D) 0.50 J/go
Answer:
The specific heat capacity is 0.67 [tex]\frac{J}{g*C}[/tex]
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
The amount of heat that a body receives or transmits is determined by the following expression:
Q = c * m * ΔT
Where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
This expression indicates that between heat and temperature there is a direct proportional relationship.
In this case:
Q= 100 Jc= ?m= 5 gΔT= Tfinal - Tinitial= 40 °C - 10 °C= 30 °CReplacing:
100 J= c*5 g* 30°C
Solving:
[tex]c=\frac{100 J}{5 g* 30C}[/tex]
c= 0.67 [tex]\frac{J}{g*C}[/tex]
The specific heat capacity is 0.67 [tex]\frac{J}{g*C}[/tex]
Inside the retina of our eyes are receptors called rods and cones. Rods measure the brightness we see and cones determine _____.
A) the color we see
B) the white we see
C) the dimness we see
D) the loudness we hear
A typical cell phone uses wavelength of 0.36meters. How much energy does this wave have?
Answer:
55×10^-26 J
Explanation:
We can calculate the energy of the wave from
E= hc/λ
Where
h= Planks constant = 6.6×10^-34 Is
c= speed of light = 3×10^8 ms-1
λ= wavelength of the wave = 0.36 metres
Recall that cell phone use radio waves which belong to the electromagnetic spectrum hence it must possess the speed of light.
E= 6.6×10^-34 × 3×10^8/ 0.36
E= 55×10^-26 J
Hence the energy possessed by 0.36 meters wavelength radio waves is 55×10^-26 J
Balance the following equation by adding the correct mole numbers.
P⁴+Cl²->PCl³
Hey there!
P₄ + Cl₂ → PCl₃
First, let's balance Cl.
There are 2 on the left, and 3 on the right.
To balance this, let's put a coefficient of 3 in front of Cl₂ and a coefficient of 2 in front of PCl₃.
P₄ + 3Cl₂ → 2PCl₃
Now we have 6 on the left and 6 on the right.
Next, let's balance P.
There are 4 on the left and 2 on the right.
Let's change the coefficient in front of PCl₃ from 2 to 4.
P₄ + 3Cl₂ → 4PCl₃
There are now 4 P on each side.
However, now Cl is unbalanced, with 6 on the left and 12 on the right.
We can change the coefficient in front of Cl₂ from 3 to 6.
P₄ + 6Cl₂ → 4PCl₃
So now, we have 4 P on each side and 12 C on each side.
This is our final balanced equation.
Hope this helps!
Answer:
1:1
Explanation:
Took test
3 2 1
1H + 1H ——> 0n + ___
Answer:
2H on 3H
Explanation:
it's because Mario eh, eh, eh. now back of and habeba goodnday
An insulator,
Keeps electrons inside the nucleus of an atom
Allow electrons to move easily through an object
Is when electrons cannot move through objects easily
The specific heat of iron is 0.107 cal/g x oC. How much heat is transferred when a 24.7 kg iron ingot is cooled from 880 oC to 13 oC?
Answer:
heat = 229139.43 cal
Explanation:
given data
specific heat of iron is 0.107 cal/g-°C C = 0.4494 J/g°C;
Mass of iron = 24.7 kg = 24700 g
temperature T1 = 880°C
temperature T2 = 13°C
solution
we know that Heat lost that is express as
heat loss = mcΔT .........................1
here m is the mass and c is specific heat capacity of iron and ΔT is the change in temperature
so here change in the temperature is = 880°C - 13°C
change in the temperature = 867°C
so put here value and we get
heat = 24700 × 0.107 cal/g-°C × 867°C
heat = 229139.43 cal
Consider a system of four gases. The equilibrium concentration of each product is 2.3 M and the equilibrium concentrations of the reactants are equal. The equilibrium is shown here:
A + B C + D K = 2.6
What is the equilibrium concentration of gas A?
Answer:
The equilibrium concentration of gas A is 1.43 M
Explanation:
Here we have the reaction expressed as follows;
A + B → C + D and
The formula for equilibrium constant is therefore presented as follows;
[tex]K = \frac{[C]\times [D]}{[A]\times [B]}[/tex]
Where:
[C] = [D] = 2.3 M
[A] = [B]
K = 2.6
Hence, we have;
[tex]2.6 = \frac{2.3\times 2.3}{[A]\times [A]} = \frac{5.29}{[A]^2}[/tex]
[tex][A]^2= \frac{5.29}{2.6} = 2.03[/tex]
[A] = 1.43 M
The equilibrium concentration of gas A = 1.43 M.
Answer:
The equilibrium concentration of gas A = 1.43 M
Explanation:
First set up the equilibrium expression:
[tex]K = \frac{[C]\times [D]}{[A]\times [B]}[/tex]
The problem states that each product has a concentration of 2.3M at equilibrium, and that k=2.6
We also know that [A] and [B] are the same.
Since we are solving for [A] I'm going to change [A][B] to A²
[tex]2.6 =\frac{2.3^2}{A^2}[/tex]
Now we just need to solve for A²
A² = 5.29 / 2.6
A² = 2.0346
A = √2.0346
A = 1.43
Therefore, the equilibrium concentration of gas A = 1.43 M.
I need simple answers that a 14-year-old would understand.
What are valence electrons?
What is the difference between the Rutherford and Thompson plum pudding model?
What relative scale for atoms do chemists use? Why do they use this?
Compare and contrast alpha, beta and gamma decay of radionuclides.
Explain why radiation is dangerous for living cells but can be applied to treat people with some forms of cancer.
Explain why oxygen atoms ionise to form the oxide ion with a charge of –2. Identify if oxide is an anion or a cation.
Answer:
1. The Nummber of electrons present in the outermost shell is called Valence electrons.
2. Thomson model:
Thomson model of atom is the model which states that electrons are embedded in a positively charged solid material which is spherical in shape.
Rutherford model
Rutherford model of atom is the model which explains that there is a nucleus in the center of the atom and electrons are located around the nucleus.
3. Relative atomic mass. Atoms have very little mass , so they're difficult to measure accurately. Instead, chemists use a scale. On this scale the mass of a 12C atom is exactly 12.
4. Difference between Alpha, Beta and Gamma radioactive decay:
Alpha decay forms new element with two fewer protons and two fewer neutrons;
Beta decay forms new element with one more proton and one fewer neutron.
Gamma decay forms NO new element, but now the element has less energy because energy is released as gamma rays.
Gamma radiation has the highest penetration power, Beta decay goes the second, alpha decay the last. However, alpha particles make the most damage even if it has the lowest penetration power among the three.
5. This species has a 2− charge on it, so it is an anion. Anions are named using the stem of the element name with the suffix -ide added. This is the oxide anion.
Hope it helps....Pls Mark as Brainliest!! I Have answered all your question in the Simplest way i could...
An ion with a -2 charge has? A) one missing protein B) two missing protons c) two missing electrons D) two extra electrons
Answer:
D.
Explanation:
It would not be gain because it would say +6 instead of -2. Having a -2 charge means it wants to loose 2 electrons so it can form a full shell of 8 electrons. It wants to be inert (stable).
- Hope that helps! Please let me know if you need further explanation.
if the volume and Kelvin temperature are reduced by one-half what will happen to the pressure???
Answer:
the pressure will decrease
Explanation:
Ideal gas law is valid only for ideal gas not for vanderwaal gas. The pressure will remain same as the initial pressure on decreasing volume and temperature by half.
What is ideal gas equation?Ideal gas equation is the mathematical expression that relates pressure volume and temperature. real gas can become ideal gas at low pressure and high temperature.
Mathematically the relation between Pressure, volume and temperature can be given as
PV=nRT
where,
P = pressure of gas
V= volume of gas =1/2V
n =number of moles of gas
T =temperature of gas =T/2
R = Gas constant = 0.0821 L.atm/K.mol
Substituting all the given values we get
P×(V/2)=nR(T/2)
(PV)/2=(nRT)/2
PV=nRT
Therefore, the pressure will remain same as the initial pressure on decreasing volume and temperature by half.
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What are the oxidizing agent and the reducing agent in this chemical equation?
3Fe5 + 8HNO3 + 3FeSO4 + 8NO + 4H20
A) Fes is the oxidizing agent, and HNO3 is the reducing agent.
B) HNO3 is the oxidizing agent, and NO is the reducing agent.
C) Fes is the reducing agent, and HNO3 is the oxidizing agent.
D) HNO3 is the reducing agent, and NO is the oxidizing agent.
Answer:
C.
Fe goes from 0 to 2+, oxidation. It is reducing agent
N goes from 5+ to 2+, reduction. It is oxidizing agent
Explanation:
Oxidation number
Fe (s) has 0
FeSO4 has 2+
HNO3 N has 5+
NO N has 2+
ANSWER
C is the answer just trust me plz I GOOGLED it
#Google works # Big Brains
Explanation:
please help! Which halogen has the strongest IMF and why?
Answer:
The larger the species, the further away from the nucleus the outer electrons are and hence the less strongly they are held. This means the bigger atoms will be more polarizable. So, the order from biggest-smallest molecules (strongest to weakest IMF) is iodine, bromine and finally chlorine.
Explanation:
One scientist discovered an accurate way to measure the temperature of planets. When would the scientist's discovery most likely develop into a theory? (2 points) when the discovery is demonstrated to others when no other scientist is able to get results of the same accuracy when the results are published in a newspaper when the scientific community retests and accepts the results
Answer:
When the scientific community retest and accepts the results
Explanation:
Mark me brainlist pls
How many moles of gas fill a 2.2 L vessel with a pressure of 1.2 atm at 25.0 °C?
P=
V=
n=
R=
T=
Formula:
Answer:
Do you still need this answer? If you do i can provide it for you still
Thank you
With your bare feet, stand with one foot on a rug, and the other foot on a tile, linoleum, or wood floor. Which one feels colder? Which one is really colder?
Answer:
I would say the wood floor because it's really cold. I hope this helps you out ☺️
Explanation:
Answer: i would say tile floor just because it gets cold around and is not able to be heated like carpet lol
Explanation:
