Write the balanced half-reactions and an overall cell reaction below. Be sure to include states of matter.

Answers

Answer 1

Answer: Hello your question is incomplete attached below is the missing image

answer:

Reduction half-reaction: Zn(s) ⇒ Zn⁺² (aq)  + 2e⁻ ( occurs at anode )

Oxidation half-reaction; CO²⁺(aq) + 2e⁻ ⇒ CO (s)  ( occurs at the cathode )

Overall cell reaction ; Zn(s)  + CO²⁺(aq)  ⇒ Zn⁺² (aq) +  CO (s)

Explanation:

stating the standard reduction potentials

E° zn²⁺/zn = -0.76 v

E°Co²⁺ / Co = -0.28 v

since ; -0.76 v  < -0.28 v.    Zn will be oxidized while Co²⁺ will be reduced .

Reduction half-reaction: Zn(s) ⇒ Zn⁺² (aq)  + 2e⁻ ( occurs at anode )

Oxidation half-reaction;  CO²⁺(aq) + 2e⁻ ⇒ CO (s)  ( occurs at the cathode )

hence the

Overall cell reaction ;

Zn(s)  + CO²⁺(aq)  ⇒ Zn⁺² (aq) +  CO (s)

Write The Balanced Half-reactions And An Overall Cell Reaction Below. Be Sure To Include States Of Matter.

Related Questions

Calculate the solubility of copper(II) hydroxide, Cu(OH)2, in g/L​

Answers

Answer:

Ksp = [ Cu+² ] [ OH-] ²

molar mass Cu(oH )2 ==> M= 63.546 (1) + 16 (2) + 1 (2) = 97.546 g/mol

Ksp = [ Cu+² ] [ OH-] ²

Ksp [ cu (OH)2 ] = 2.2 × 10-²⁰

|__________|___Cu+² __|_2OH-____|

|Initial concentration(M)|___0__|_0______|

|Change in concentration(M)|_+S |__+2S__|

|Equilibrium concentration(M)|_S _|2S___|

Ksp = [ Cu+² ] [ OH-] ²

2.2 ×10-²⁰ = (S)(2S)²= 4S³

[tex]s = \sqrt[3]{ \frac{2.2 \times {10}^{ - 20} }{4} } = 1.8 \times {10}^{ - 7} [/tex]

S = 1.8 × 10-⁷ M

The molar solubility of Cu(OH)2 is 1.8 × 10-⁷ M

Solubility of Cu (OH)2 =

[tex]Cu (OH)2 = \frac{1.8 \times {10}^{ - 7} mol \:Cu (OH)2 }{1L} \times \frac{97.546 \: g \: Cu (OH)2}{1 \: mol \: Cu (OH)2} \\ = 1.75428 \times 10 ^{ - 5} [/tex]

Solubility of Cu (OH)2 = 1.75428 × 10 - g/ L

I hope I helped you^_^

The first step of electrophilic aromatic substitution involves the formation of the arenium ion intermediate.

a. True
b. Fasle

Answers

Answer:

True

Explanation:

Aromatic compounds undergo substitution rather than addition reactions because the aromatic structure is maintained.

Electrophilic aromatic substitution begins with attack of the electrophile on the aromatic ring to yield a delocalized intermediate called the arenium intermediate. Loss of hydrogen from this intermediate yields the final product.

A student isolated an unknown organic compound through extraction. The student measures the melting point and fins it to be 115-122 C. The student looks through the list of possible strucures and decides the comound is most likely 2-napthol. Do you believe this choice is correct?

Answers

Hope this helps!

https://www.chegg.com/homework-help/questions-and-answers/student-isolated-unknown-organic-compound-extraction-student-measures-melting-point-finds--q77093697

The Halogen Group is also known as the?

salt formers
acid makers

Answers

Answer:

I think b acid makers

Explanation:

hope it will help you

What is the molarity of a solution that contains 17g of NH₃ in 0.50L of solution?

Please explain as well!

Answers

Explanation:

Because molarity is mol/L, we'll have to convert 17g to mol.

After obtaining the mol, we'll divide that by the volume to obtain Molarity.

Molar mass of Ammonia:-

[tex]\\ \sf\longmapsto NH_3[/tex]

[tex]\\ \sf\longmapsto 14u+3(1u)[/tex]

[tex]\\ \sf\longmapsto 14u+3u[/tex]

[tex]\\ \sf\longmapsto 17u[/tex]

[tex]\\ \sf\longmapsto 17g/mol[/tex]

Moles of Ammonia:-

[tex]\boxed{\sf No\:of\:moles =\dfrac{Given\:mass}{Molar\:mass}}[/tex]

[tex]\\ \sf\longmapsto No\:of\:moles=\dfrac{17}{17}[/tex]

[tex]\\ \sf\longmapsto No\;of\:moles=1mol[/tex]

Volume of solution=0.50L

We know

[tex]\boxed{\sf Molarity=\dfrac{Moles\:of\:solute}{Volume\:of\: Solution\:in\:L}}[/tex]

[tex]\\ \sf\longmapsto Molarity=\dfrac{1}{0.50}[/tex]

[tex]\\ \sf\longmapsto Molarity=2M[/tex]

A piece of metal has a volume of 30.0cm3 and a mass of 252g. What is its density? what metal do you think this is?

Answers

Answer:

Explanation:

get density = D = m / V = 0.252 / 0.00003 = 8400 metal will be Cu => bronze

Nicotine is a toxic substance present in tobacco leaves. There are two lone pairs in the structure of nicotine. In general, localized lone pairs are much more reactive than delocalized lone pairs. With this information in mind, do you expect both lone pairs in nicotine to be reactive?
A. Both lone pairs are delocalized and, therefore, both are expected to have the same reactivity.
B.Lone pair in pyrrolidine ring is localized and, therefore, is expected to be more reactive.
C. Both lone pairs are localized and, therefore, both are expected to be reactive.
D. Lone pair in pyridine ring is localized and, therefore, is expected to be more reactive.

Answers

Answer:

B.Lone pair in pyrrolidine ring is localized and, therefore, is expected to be more reactive.

Explanation:

There are two nitrogen atoms bearing lone pairs of electrons in the structure of nicotine as shown in the image attached.

One nitrogen atom is found in the pyrrolidine ring. The lone pair on this nitrogen atom is localized hence it is more reactive than the lone pair of electrons found on the nitrogen atom in the pyridine ring which is delocalized a shown in the image attached to this answer.

number is equal to 6022 x 10^23

Answers

Answer:

The Avogadro's number

Explanation:

the number is 6.02214x10 to the 23 power

If position vector r=bt²i + ct³j, where c are positive constants, when does the velocity vector make an angle of 45° with the x and y axes?

Answers

We want to find the value of t such that the velocity vector makes an angle of 45° with both axes.

We found that:

t = (2/3)*(b/c)

The velocity vector makes an angle of 45° with the x and y axes.

We know that the position vector is:

r = r=b*t²i + c*t³j

Remember that the versor "i" corresponds to the x-component, and the versor "j" corresponds to the y-component, then:

r = r=b*t²i + c*t³j  = (b*t², c*t³)

The velocity vector is the vector that we get when we differentiate the position one, remember that if:

f(x) = a*x^n

then

f'(x) = n*a*x^(n - 1)

Using this, we can find that the velocity vector is:

v = (2*b*t,  3*c*t²)

Now we want to know, when does the velocity vector make an angle of 45° with the x and y axes.

Let's think of the vector as the hypotenuse of a triangle rectangle, where the x-component is the adjacent cathetus, and the y-component is the opposite cathetus. (so the angle is measured counterclockwise from the x-axis)

We have the trigonometric equation:

tan(a) = (opposite cathetus)/(adjacent cathetus)

So now we can replace these things with the known ones:

a = 45°

opposite cathetus = y-component = 3*c*t²

adjacent cathetus = x-component = 2*b*t

So we will get:

tan(45°)  =  (3*c*t²)/( 2*b*t)

1 = (3/2)*(c/b)*t

Now we can solve this for the variable, t.

1*(2/3)*(b/c) = t

t = (2/3)*(b/c)

We can conclude that at the time:

t = (2/3)*(b/c)

The velocity vector makes an angle of 45° with the x and y axes.

You can read more about vectors in:

https://brainly.com/question/10841907

Which of the following is most likely to happen when a sound wave reflects
off a hard surface? (Assume that neither the source of the sound nor the hard
surface is moving.)
A. A change in speed
B. An echo
C. A change in pitch
D. A beat frequency

Answers

В

an echo is caused by the fact that waves can be reflected by solid surfaces, this is due to the dynamic pattern of rarefactions and air seals near the reflecting surface

(in the image)
What Is the noble gas configuration for strontium (atomic number = 38)? Given: He (atomic number = 2) Ne (atomic number = 10) Ar (atomic number = 18) Kr (atomic number = 36) B В A [Kr 45Kr 5​

Answers

Answer:

[Kr] 5s²

Explanation:

From the question given above, the following data were obtained:

Atomic number of strontium (Sr) = 38

Electronic configuration =?

Next, we shall determine the electronic configuration of the noble gas element before strontium (Sr).

The noble gas element before strontium (Sr) is krypton (Kr). Thus, the electronic configuration of krypton (Kr) is given below:

Kr (36) => 1s² 2s²2p⁶ 3s²3p⁶ 3d¹⁰ 4s²4p⁶

Finally, we shall determine the electronic configuration of strontium (Sr). This can be obtained as follow:

Kr (36) => 1s² 2s²2p⁶ 3s²3p⁶ 3d¹⁰ 4s²4p⁶

Sr (38) =>?

Sr (38) => 1s² 2s²2p⁶ 3s²3p⁶ 3d¹⁰ 4s²4p⁶ 5s²

But

Kr (36) => 1s² 2s²2p⁶ 3s²3p⁶ 3d¹⁰ 4s²4p⁶

Therefore,

Sr (38) => [Kr] 5s²

How many grams of sodium chloride are contained in 250.0 g of a 15% NaCl solution?

Please explain and show work.

Answers

Given concentration of NaCl=15%

Means ,

In every 100g of Solution 15g of NaCl is present .

Now

Given mass=250g

So ,

[tex]\\ \Large\sf\longmapsto 250\times 15\%[/tex]

[tex]\\ \Large\sf\longmapsto 250\times \dfrac{15}{100}[/tex]

[tex]\\ \Large\sf\longmapsto 37.5g[/tex]

37.5g of NaCl present in 250g of solution.

Answer:

Given concentration of NaCl=15%

Means ,

In every 100g of Solution 15g of NaCl is present .

Now

Given mass=250g

So ,

➡250 × 15%

➡250×15/100

➡37.5g

37.5g of NaCl present in 250g of solution.

Which of the following statements is/are correct? 1. There are 5 orbitals in
the d subshell. 2. The d orbitals can accommodate 14 electrons. 3. The first
shell contains s and p orbitals. 4. The s orbital can accommodate 2 electrons.

A. 1 and 4
B. 2 and 3
C. 3 and 4
D. 2 and 4

Answers

?? Como dices entonces hablas english

A sample of oxygen gas at a pressure of 1.19 atm and a temperature of 24.4 °C, occupies a volume of 18.7 liters. If the gas is allowed to expand at constant temperature to a volume of 29.4 liters, the pressure of the gas sample will be ______ atm.

Answers

Answer:

[tex]\boxed {\boxed {\sf 0.757 \ atm}}[/tex]

Explanation:

We are asked to find the pressure of a gas given a change in volume. Since the temperature remains constant, we are only concerned with volume and pressure. We will use Boyle's Law, which states the volume is inversely proportional to the pressure. The formula for this law is:

[tex]P_1V_1= P_2V_2[/tex]

Initially, the oxygen gas occupies a volume of 18.7 liters at a pressure of 1.19 atmospheres.

[tex]1.19 \ atm * 18.7 \ L = P_2V_2[/tex]

The gas expands to a volume of 29.4 liters, but the pressure is unknown.

[tex]1.19 \ atm * 18.7 \ L = P_2 * 29.4 \ L[/tex]

We are solving for the new pressure, so we must isolate the variable [tex]P_2[/tex]. It is being multiplied by 29.4 liters. The inverse operation of multiplication is division. Divide both sides of the equation by 29.4 L.

[tex]\frac {1.19 \ atm * 18.7 \ L}{29.4 \ L} =\frac{ P_2 * 29.4 \ L}{29.4 \ L}[/tex]

[tex]\frac {1.19 \ atm * 18.7 \ L}{29.4 \ L} =P_2[/tex]

The units of liters cancel.

[tex]\frac {1.19 \ atm * 18.7 }{29.4 } =P_2[/tex]

[tex]\frac {22.253}{29.4 } \ atm = P_2[/tex]

[tex]0.7569047619 \ atm =P_2[/tex]

The original measurements all have 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place. The 9 in the ten-thousandth place to the right of this place tells us to round the 6 up to a 7.

[tex]0.757 \ atm \approx P_2[/tex]

The pressure of the gas sample is approximately 0.757 atmospheres.

Answer:

According to Boyle's law, for a given mass of ideal gas, pressure of gas is inversely proportional to the volume of gas, Provided the Temprature remains constant.

P₁ = 1.19 atmP₂ = ?V₁ = 18.7 LV₂ = 29.4 LT = constant = 24.4° C = Isothermal process

[tex]\implies \sf P_1 V_1 = P_2 V_2 \\ [/tex]

[tex]\implies \sf 1.19 \times 18. 7= P_2 \times 29.4 \\[/tex]

[tex]\implies \sf 22.253= P_2 \times 29.4 \\[/tex]

[tex]\implies \sf P_2 = \dfrac{22.253}{29.4} \\[/tex]

[tex]\implies \underline{ \red{\boxed{ \bf P_2 \approx0.756 \: atm }}} \\[/tex]

How does a smoke detector utilize radiation?

A. Beta radiation creates a stead stream of electrons. When the stream is broken by smoke particles, it sets off the alarm.
B. Alpha radiation ionizes the air. When smoke interacts with the ionized particles it causes the alarm to sound.
C. Gamma radiation creates a stead stream of electrons. When the stream is broken by smoke particles, it sets off the alarm.
D. Beta radiation ionizes the air. When smoke interacts with the ionized particles it causes the alarm to sound.

Answers

D. Beta radiation ionizes the air. When smoke
interacts with the ionized particles it causes the
alarm to sound.

A 25.0 mL sample of 0.150 M hypochlorous acid is titrated with a 0.150 M NaOH solution. What is the pH at the equivalence point? The Kaof hypochlorous acid is 3.0x10^-8.
a) 10.20
b) 7.00
c) 6.48
d) 7.52
e) 14.52

Answers

Answer:

pH = 10.20

Explanation:

The HClO reacts with NaOH as follows:

HClO + NaOH → H2O + NaClO

Where HClO and NaOH react in a 1:1 reaction.

As the concentration of both reactions is the same and the reaction is 1:1, to reach equivalence point are required the same 25.0mL.

And the NaClO produced decreases its concentration in 2 because the volume is doubled.

The concentration of NaClO is: 0.150M / 2 = 0.075M

The equilibrium of NaClO is:

NaClO(aq) + H2O(l) ⇄ HClO(aq) + OH-(aq)

Where Kb of reaction is 1.0x10⁻¹⁴ / Ka =

1.0x10⁻¹⁴ / 3.0x10⁻⁸ = 3.33x10⁻⁷ = [HClO] [OH-] / [NaClO]

[NaClO] = 0.075M

As both HClO and OH- comes from the same equilibrium,

[HClO] = [OH-] = X

Where X is the reactoin coordinate

Replacing:

3.33x10⁻⁷ = [X] [X] / [0.075M]

2.5x10⁻⁸ = X²

X = 1.58x10⁻⁴M = [OH-]

pOH = -log [OH-]

pOH = 3.80

pH = 14 - pOH

pH = 10.20

Which of the following represents a physical change?

Answers

Answer:

» Water evaporating to gas.

» Solid subliming to gas.

» Water freezing to solid.

» Solid melting to liquid.

Explanation:

[tex]{ \underline{ \blue{ \sf{christ \:† \: alone }}}}[/tex]

90
1
39
is the
In the following decay equation,
90
Sy →
38
et
90
39
-1
A. alpha particle
B. parent element
C. daughter element
D. beta particle

Answers

Answer:

D. beta particle

Explanation:

Number of protons increases from 38 to 39 indicating beta decay (only one proton up from parent isotope to daughter isotope) Also atomic mass (on top of an isotope), 90 stays the same as beta particle is very small.

Which one of the following compounds will NOT be soluble in water?
A) LiNO3
B) PbS
C) NaOH
D) MgCl2
E) K2SO4

Answers

See the correct answer is b.)PbS

12.39 HBr can be added to alkenes in either the absence or presence of peroxides (producing either the Markovnikov or the anti-Markovnikov addition product). What intermediates leading to the formation of the major product are observed when 1-butene is treated with 1) HBr or 2) HBr/peroxides

Answers

Answer:

See explanation and image attached

Explanation:

The reaction of HBr with 1-butene is an addition reaction. The HBr adds across the double bond to yield a saturated halogenoalkane.

In the absence of peroxides, the reaction proceeds in accordance with Markovnikov rule which states that;''the negative part of the addendum, is attached to the carbon atom with the least number of hydrogen atoms attached.'' This occurs in the first reaction shown in the image.

In the presence of peroxides, the reaction proceeds in an anti-Markovnikov manner to yield the product shown in the second reaction.

For the following reaction, 5.29 grams of water are mixed with excess diphosphorus pentoxide. The reaction yields 13.3 grams of phosphoric acid . diphosphorus pentoxide(s) + water(l) phosphoric acid(aq). What is the theoretical yield of phosphoric acid?

Answers

Answer:

19.2 g

Explanation:

Step 1: Write the balanced equation

P₂O₅(s) + 3 H₂O(l) ⇒ 2 H₃PO₄

Step 2: Calculate the moles corresponding to 5.29 g of H₂O

The molar mass of H₂O is 18.02 g/mol.

5.29 g × 1 mol/18.02 g = 0.294 mol

Step 3: Calculate the theoretical yield of phosphoric acid, in moles

The molar ratio of H₂O to H₃PO₄ is 3:2. The theoretical yield of H₃PO₄ is 2/3 × 0.294 mol = 0.196 mol

Step 4: Calculate the mass corresponding to 0.196 moles of H₃PO₄

The molar mass of H₃PO₄ is 97.99 g/mol.

0.196 mol × 97.99 g/mol = 19.2 g

An outdoor gear company develops a new type of fabric that works with electricity to warm the body without interfering with motion like heavy jackets do. Research biologists, studying life in extremely cold conditions on the polar ice caps, begin wearing the new fabric because it helps them work more comfortably, and they find it increases their productivity.

What best describes how the processes of scientific investigation and technological design are involved in this situation?

The clothing company conducted a scientific investigation to communicate results to researchers, who then used the knowledge in a technological design.
The clothing company conducted a scientific investigation to produce a product that researchers could then test while designing new technology.
The clothing company used technological design to create a product that helped aid researchers conducting a scientific investigation.
The clothing company designed a new technology that provided information researchers needed in order to continue with their scientific investigation.

Answers

The answer is C. The clothing company used technological design to create a product that helped aid researchers conducting a scientific investigation.

Answer:

C: The clothing company used technological design to create a product that helped aid researchers conducting a scientific investigation.

Explanation:

I just did the assignment on EDGE2020 and it's 200% correct!  

Also, heart and rate if you found this answer helpful!! :) (P.S It makes me feel good to know I helped someone today!!)  :)  

oxidation number of Ni in Ni(CO)4 is​

Answers

Answer:

0

Explanation:

answer from gauth math

C2H5MgBr + PCl3 ra chất gì

Answers

Answer:

C2H5P

is the right answer

What is the formula for the compound made from mercury (II) and the nitrate ion.

Answers

Answer:

Hg(NO3)2

Explanation:

Hg occurs both as Hg(I) and Hg(II) but nitrate is -1, not -2 We NORMALLY use the smallest set of subscripts but in the case of Hg(I) compounds, most of them are dimeric. Hg2Cl2, Hg2(NO3)2, etc. Note that there also is a mercury(II) nitrate; i.e., Hg(NO3)2. Therefore, although the empirical formula for mercury(I) nitrate is HgNO3, the molecular formula is Hg2(NO3)2 anf I was always encouraged to write the molecular formula instead of the empirical formula.

Hope this helps! Feel free to shoot me any questions <3

Please help with all 3 parts!

Answers

Answer:

1:Part A.

[tex]\bold{42.2 g C_{12}H_{22}O_{11} \:in \:528 g H₂O}[/tex]

Mass Percent=[tex]\bold{\frac{Mass\: of \:Solute}{Mass\: of \:Solution}×100\%}[/tex]

=[tex]\frac{42.2}{528}*100\%=\bold{\underline{7.99\: or \:8\%}}[/tex]

Part B.

[tex]\bold{198\:m g\: C_{6}H_{12}O_{6} \:in\:4.71 g\: H₂O}[/tex]

mass of solute: 198mg

mass of solvent :4.71g=4710g

Mass Percent=[tex]\bold{\frac{Mass\: of \:Solute}{Mass\: of \:Solution}×100\%}[/tex]

=[tex]\frac{198}{4710}*100\%=\bold{\underline{4.20\%}} [/tex]

Part C.

[tex]\bold{8.85 g NaCl \:in \:190 g\: H₂O}[/tex]

Mass Percent=[tex]\bold{\frac{Mass\: of \:Solute}{Mass\: of \:Solution}×100\%}[/tex]

=[tex]\frac{8.85}{190}*100\%=\bold{\underline{4.66\%}}[/tex]

Answer:

It will help you !!!!!!!!!!

calculate the pH of 0.01moldm-3 of trioxonitrate (v) acid​

Answers

Answer:

pH = 2

Explanation:

Trioxonitrate (v) acid​ is also known as nitric acid (HNO₃) and is one of the strong acid set which when dissolved in water, ionizes 100%. That is,

0.01M HNO₃ => 0.01M H⁺ + 0.01M NO₃⁻ => pH = -log[H⁺] = -log(0.01) = -(-2) = 2

what is the mass of cerrusite would contain 35g of lead?​

Answers

Answer:

i believe its 42

Explanation:

Balance the following equations Ag (s) + H₂ S(g) + 0₂ (g) → Ag₂ S(₅) + H₂0

Answers

Answer:

2Ag(s) + 2H²S(g) + O2(g) ➡️ Ag2S(s) + 2H2O(g)

Explanation:

Sorry for my typo. but you understand

HELP! How is the mass number of an atom calculated?
A - total number of electrons

B - total number of protons

C - protons plus neutrons

D - electrons plus neutrons

Answers

The answer is C. Mass number = protons + neutrons
Other Questions
CHANGE THE FOLLOWING SENTENCES INTO INDIRECT SPEECH1. Anuj said, I will leave for Delhi tomorrow.2. My uncle said to me, I am tired now.3. I said, I am waiting for my sister to arrive.4. The teacher said to us, you are very naughty.5. Veena said to her mother, I have finished my homework.6. Mr. Ravi said to his neighbor, My house is being built.7. Mrs. Gupta said to the doctor, My baby was crying all night.8. Chitra said, I will go to the shop today.9. The old man said to me, I have been trying to cross the road, but have not beenable to do so.10. Poonam said, I do not know how to make tea. When parents are unable to resolve the conflicts between them, a common pattern is to continue to argue through the children. When father says mother is too permissive, mother says father is too strict. Father may in turn withdraw, and mother responds to the child with excessive concern, focus, and devotion. The structural term which best describes the resulting family structure is _______________. Brian rolls 2 fair dice and adds the results from each.Work out the probability of getting a total that is prime Anybody good in English and know this? please help me with some geography report or research ideas... which of the following is not an outcome for JUK ? Can someone help me please Find the area of a circle that has a radius of 60.4 m. Put your answer as yards squared rounded to 1 decimal. What is cookery method used in this dish honey soy drumettes Which of the following are not used to prevent flooding during storms?A.damsB.levees C.breakwaters D.sandbags Finding angle measures given two intersecting lines The following is TRUE about Inventory: A. Firms increase inventory because there is an opportunity cost to holding inventory B. Firms increase inventory because more inventory sitting for longer periods of time present more opportunities for damage, errors, rework, theft, and obsolescence C. Firms increase inventory because more inventory means more movement of materials D. Firms increase inventory because there is a risk of significant and unpredictable fluctuations in downstream demand E. Firms increase inventory because the more we spend on inventory, the more we need to spend on other inventory-related expenditures Plz answer my question i asked before this (plz, i will give brainliest to u if answered correctly) Which of the following functions is graphed below? Explain the effect of a price ceiling on the quantity by ceiling and the quantity of a good and who this intervention intends to assist Where is CO2 concentration greatest in the body? State what is meant by a gravitational potential at point A is -170 109 J kg-1. please helpWhich is the graph of f(x) = 2 (4)x? please help with geometry Which similarity statement is true?