Answer:
quartz
Explanation:
The correct option would be quartz.
Allotropy is a phenomenon that describes the natural existence of the same element in different forms with different physical characteristics. Allotropes are therefore different forms of the same element.
Carbon as an element has several allotropes which include diamond, graphite, graphene, amorphous carbon, and fullerenes. Quartz is a crystalline solid that is composed of silicon dioxide and not carbon.
Hence, all the options are carbon allotropes except quartz.
Which one of the following is not matches the organelle with its function
Answer:
rip there isnt a photo
Explanation:
i do know a lot about cells tho lol
f a substance has a half-life of 8.10 hr, how many hours will it take for 75.0 g of the substance to be depleted to 3.90 g?
Answer:
35 hrs
Explanation:
half life of the substance [tex]t_{1/2 }[/tex] = 8.1 hr
initial amount [tex]N_{0}[/tex] = 75 g
The final amount [tex]N[/tex] = 3.9 g
The time elapsed [tex]t[/tex] = ?
we use the relationship
[tex]N[/tex] = [tex]N_{0}[/tex] [tex](\frac{1}{2} )^{\frac{t}{t_{1/2} } }[/tex]
substituting values, we have
3.9 = 75 x [tex]\frac{1}{2}^{\frac{t}{8.1} }[/tex]
0.052 = [tex]\frac{1}{2}^{\frac{t}{8.1} }[/tex]
take the log of both side
log 0.052 = log [tex]\frac{1}{2}^{\frac{t}{8.1} }[/tex]
log 0.052 = [tex]\frac{t}{8.1}[/tex] log 1/2
-1.284 = [tex]\frac{t}{8.1}[/tex] x -0.301
1.284 = 0.301t/8.1 =
1.284 = 0.0372t
t = 1.284/0.037 = 34.5 ≅ 35 hrs
What was Thomson's model of the atom called?
A. The oil-drop model
B. The photoelectric model
C. The plum-pudding model
D. The atomic theory model
Q 11.20: What is the product of the reaction between t-BuCl and MeOH? A : t-BuOH B : MeOCl C : t-BuOMe D : (CH3)2CCH2
Answer:
C : t-BuOMe
Explanation:
The tert -butanol is a tertiary alcohol and when chloride ion attacks the carbocation, it forms t-BuCl.
The reaction of tert-butyl chloride or t-BuCl ((CH3)3C−Cl) with methanol and MeOH (CH3−OH) gives the product tert-Butyl methyl ether or t-BuOMe (CH3)3C−OCH3:
(CH3)3C−Cl + CH3−OH => (CH3)3C−OCH3 + HCl
Hence, the correct asnwer is C : t-BuOMe
Zinc is used as a coating for steel to protect the steel from environmental corrosion. If a piece of steel is submerged in an electrolysis bath for 24 minutes with a current of 6.5 Amps, how many grams of zinc will be plated out? The molecular weight of Zn is 65.38, and Zn+2 + 2e– → Zn. Question 7 options: A) 3.17 g of Zn B) 1.09 g of Zn C) 6.34 g of Zn D) 12.68 g of Zn
Answer:
A) 3.17 g of Zn
Explanation:
Let's consider the reduction of Zn(II) that occurs in an electrolysis bath.
Zn⁺²(aq) + 2e⁻ → Zn(s)
We can establish the following relations:
1 min = 60 s1 A = 1 C/sThe charge of 1 mole of electrons is 96,468 C (Faraday's constant).When 2 moles of electrons circulate, 1 mole of Zn is deposited.The molar mass of Zn is 65.38 g/molThe mass of Zn deposited under these conditions is:
[tex]24min \times \frac{60s}{1min} \times \frac{6.5C}{s} \times \frac{1mol\ e^{-} }{96,468C} \times \frac{1molZn}{2mol\ e^{-}} \times \frac{65.38g}{1molZn} = 3.17 g[/tex]
Answer:
A.) 3.17
Explanation:
I got it right in class!
Hope this Helps!! :))
candium forms the ion Sc3+. How many bromite ions could bond with Sc3+, and what would be the chemical formula?
a.3 bromite ions, Sc(Broa)2
b.2 bromite ions, Sc(BrO4)3
c.3 bromite ions, Sc(Broz)
d.2 bromite ions, Sc (BrO2)2
Answer: 3 bromite ions and [tex]Sc(BrO_2)_3[/tex]
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here scandium is having an oxidation state of +3 called as [tex]Sc^{3+}[/tex] cation and bromite is an anion with oxidation state of -1 called as [tex]BrO_2^-[/tex]. Thus 1 Scandium ion combines with three bromite ions and their oxidation states are exchanged and written in simplest whole number ratios to give neutral [tex]Sc(BrO_2)_3[/tex]
Answer:
3 bromite ions and
Explanation:
At 25 °C, only 0.0990 mol of the generic salt AB3 is soluble in 1.00 L of water. What is the Ksp of the salt at 25 °C? AB3(s)↽−−⇀A3+(aq)+3B−(aq)
Answer:
[tex]Ksp=2.59x10^{-3}[/tex]
Explanation:
Hello,
In this case, given the 0.0990 moles of the salt are soluble in 1.00 L of water only, we can infer that the molar solubility is 0.099 M. Next, since the dissociation of the salt is:
[tex]AB_3\rightleftharpoons A^{3+}+3B^-[/tex]
The concentrations of the A and B ions in the solution are:
[tex][A]=0.099 \frac{molAB_3}{L}*\frac{1molA}{1molAB_3} =0.0099M[/tex]
[tex][B]=0.099 \frac{molAB_3}{L}*\frac{3molB}{1molAB_3} =0.000.297M[/tex]
Then, as the solubility product is defined as:
[tex]Ksp=[A][B]^3[/tex]
Due to the given dissociation, it turns out:
[tex]Ksp=[0.099M][0.297M]^3\\\\Ksp=2.59x10^{-3}[/tex]
Regards.
The density of toluene (C7H8) is 0.867 and that of thiophene (C4H4S) is 1.065 g/ml. A solution is made by dissolving 10.00g thiophene in 250.00ml of toluene. a)Calculate the molarity of the solution
b)Assuming the volume are addictive ,calculate the molarity of the solution
Answer:
Calcular la molaridad de una solución que se preparó disolviendo 14 g de KOH en suficiente
agua para obtener 250 mL de solución. (masa molar del KOH = 56 g/mol).
Resolución: de acuerdo a la definición de “molaridad” debemos calcular primero, el número de mol de soluto (KOH) que
se han disuelto en el volumen dado, es decir, “se transforma g de soluto a mol de soluto” por medio de la masa molar,
así:
56 g de KOH 14 g de KOH
----------------- = ------------------- X = 0,25 mol de KOH
1 mol X
Ahora, de acuerdo con la definición de molaridad, el número de mol debe estar contenido en 1000 mL (o 1 L) de
solución, que es el volumen estándar para esta unidad de concentración, lo que se determina con el siguiente planteamiento:
0,25 mol X
----------------------- = ------------------------- X = 1 mol de KOH
250 mL de solución 1000 mL de solución
Explanation:
Which option draws the correct conclusion from the following case study?
A patient with sickle-cell anemia and a fever goes to the emergency room and is given Tylenol to reduce
the fever. The patient has seizures and dies after taking the Tylenol. The physician writes up this case as
an interesting outcome for a patient with sickle-cell anemia.
The case study's validity is obvious because it describes a real-life situation.
The case study was influenced by bias, and led to incorrect conclusions being drawn
The case study was not intended to produce a generalized conclusion about treatment
Upon reading this case study, physicians should stop treating sickle cell patients with fevers using Tylenol
Answer:
I believe the answer The case study was influenced by bias, and led to incorrect conclusions being drawn. plz correct me if I am wrong
Explanation:
Answer: options B
Explanation:
3,3-dibromo-4-methylhex-1-yne
Explanation:
see the attachment. hope it will help you...What happens to the rate of dissolution as the temperature is increased in a gas solution?
A.
The rate stays the same.
B.
The rate decreases.
C.
The rate increases.
D.
There is no way to tell.
Answer:
The rate decreases
Explanation:
When we dissolve a gas in a water, the process is exothermic. This implies that heat is evolved upon dissolution of a gas in water.
Recall from Le Chateliers principle that for exothermic reactions, an increase in temperature favours the reverse reaction. The implication of these is that when the temperature of the gas is increased, less gas will dissolve in water.
Hence increase in temperature decreases the rate of solubility of a gas in water.
Answer:
B.
The rate decreases.
Explanation:
A 25.00 mL sample of unknown concentration of HNO3 solution requires 22.62 mL of 0.02000 M NaOH to reach the equivalence point. What is the concentration of the unknown HNO3 solution
Answer:The concentration of the unknown HNO3 solution = 0.01809 M
Explanation:
For the acid-base reaction, HNO3 + NaOH-----> NaN03 + H20
we have that
C1 V1 = C2 V2
Where ,
C1 = concentration of HNO3=?
V1 = volume of HNO3 = 25.00 mL,
V2 = volume of NaOH = 22.62 mL,
C2 = concentration of NaOH = 0.02000 M
Therefore ,
25.00 mL x C1 = 22.62 mL x 0.02000 M
= (22.62 mL / 25.00 mL) x 0.02000 M = 0.01809 M
The concentration of the unknown HNO3 solution = 0.01809 M
Given that the Ksp value for Ca3(PO4)2 is 8.6×10−19, if the concentration of Ca2+ in solution is 4.9×10−5 M, the concentration of PO3−4 must exceed _____ to generate a precipitate.
Answer:
.0027 M
Explanation:
We must calculate the threshold concentration of PO3−4 using Ksp and the given concentration of Ca2+:
Ca3(PO4)2(s)⇌3Ca2+(aq)+2PO3−4(aq)
Ksp=8.6×10−19=[Ca2+]3[PO3−4]2=(4.9×10−5M)3[PO3−4]2
[PO3−4]=0.0027 M
Calculate ΔS∘rxn for the balanced chemical equation 2H2S(g)+3O2(g)→2H2O(g)+2SO2(g) Express the entropy change to four significant figures and include the appropriate units.
Answer:
-170.65
188.8+ 256.8-205.8-(2x205.2)
-170.65 is the entropy change.
What is Entropy Change?Entropy trade is the phenomenon that is the measure of change of disorder or randomness in a thermodynamic gadget. It is associated with the conversion of heat or enthalpy completed in work. A thermodynamic device that has extra randomness means it has high entropy.
Subtract the sum of the absolute entropies of the reactants from the sum of the absolute entropies of the products, each extended by using their suitable stoichiometric coefficients, to reap ΔS° for the reaction.
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The density of concentrated nitric acid (HNO3) is 1.413 g/mL. What volume in liters would be occupied by a mass of 47.2 g?
Answer:
The volume that a mass of 47.2 g would occupy is 0.0334 L
Explanation:
Density is the property that matter, whether solid, liquid or gas, has to compress into a given space. Density is defined as the amount of mass it has per unit volume, that is, the ratio between the mass of a body and the volume it occupies:
[tex]Density=\frac{mass}{volume}[/tex]
This indicates that density is inversely proportional to volume: the smaller the volume occupied by a given mass, the higher the density.
In this case:
density= 1.413 g/mLmass= 47.2 gvolume=?Replacing:
[tex]1.413 \frac{g}{mL}=\frac{47.2 g}{volume}[/tex]
Solving:
[tex]volume=\frac{47.2 g}{1.413\frac{g}{mL} }[/tex]
volume=33.40 mL
Being 1,000 mL= 1 L:
volume= 0.0334 L
The volume that a mass of 47.2 g would occupy is 0.0334 L
An enzyme is discovered that catalyzes the chemical reaction:SAD -------->HAPPY
<-------A team of motivated researchers sets out to study the enzyme which they call Happyase. They find that the Kcat for happyase is 600s-1. They carry out several experiments. When [Et]=20 nM and [SAD]=40 \mu M, the reaction velocity, Vo is 9.6 \mu Ms^{-1} . Calculate the Km for the substrate SAD.
Answer: Km = 10μM
Explanation: Michaelis-Menten constant (Km) measures the affinity a enzyme has to its substrate, so it can be known how well an enzyme is suited to the substrate being used. To determine Km another value associated to an eznyme is important: Turnover number (Kcat), which is the number of time an enzyme site converts substrate into product per unit time.
Enzyme veolcity is calculated as:
[tex]V_{0} = \frac{E_{t}.K_{cat}.[substrate]}{K_{m}+[substrate]}[/tex]
where Et is concentration of enzyme catalitic sites and has to have the same unit as velocity of enzyme, so Et = 20nM = 0.02μM;
To calculate Km:
[tex]V_{0}*K_{m} + V_{0}*[substrate] = E_{t}.K_{cat}.[substrate][/tex]
[tex]K_{m} = \frac{E_{t}.K_{cat}.[substrate]-V_{0}*[substrate]}{V_{0}}[/tex]
[tex]K_{m} = \frac{0.02*600*40-9.6*40}{9.6}[/tex]
Km = 10μM
The Michaelis-Menten for the substrate SAD is 10μM.
For element radon, give the chemical symbol, atomic number, and group number.
An atom of 120In has a mass of 119.907890 amu. Calculate the mass defect (deficit) in amu/atom. Use the masses: mass of 1H atom
Answer:
a
Explanation:
answer is a on edg
A nitrogen ion has a mass of 14 and a charge of +2. Which subatomic particles does it contain? (1 point)
O 2 protons, 6 neutrons, and 6 electrons
O 7 protons, 7 neutrons, and 5 electrons
O 4 protons, 4 neutrons, and 6 electrons
o 7 protons, 7 neutrons, and 9 electrons
Answer:
7 protons, 7 neutrons, and 5 electrons
Explanation:
the formula for atomic weight=no.of protons + no. of electrons this shortens the options into b or d and second part says that the ion has charge +2 which means it has lost two electrons. so no. of electrons=no.of electrons in nitrogen atom - 2=5.
Nitrogen ion with a charge of +2 has 7 protons, 7 neutrons, and 5 electrons
Explanation:
To obtain the right answer to the question, we must determine the number of proton, neutron and electron of nitrogen ion. This can be obtained as illustrated follow.
Step 1:Data obtained from the question.
Mass number = 14
Charge = +2
Step 2:Determination of the number of proton.
The atomic number of an element is simply the number of protons in the atom of the element.
Atomic number of nitrogen = 7
Thus, the proton number of nitrogen is 7.
NOTE: The atomic number of an element does not change be it atom or ion, it remains the same.
Therefore the proton number of nitrogen ion is 7
Step 3:Determination of the number of neutron
Mass number = 14
Proton number = 7
Neutron number =?Mass number = Proton + Neutron
14 = 7 + Neutron
Collect like terms
14 – 7 = Neutron
Neutron = 7Step 4Determination of the number of electrons.
Charge = +2
Proton number = 7
Electron number =?Charge = Proton – Electron
+2 = 7 – Electron
Collect like terms
2 – 7 = – Electron
–5 = – Electron
Multiply through by –1
Electron = 5SUMMARY:Nitrogen ion with a charge of +2 has:
1. 7 protons
2. 7 neutrons
3. 5 electrons.
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Question 8 of 30
When is a redox reaction spontaneous?
A. When a metal electrode is in contact with an electrolyte
B. When a power source supplies an electrical current
C. When the cell potential is positive
D. When the cell potential is negative
According to the concept of redox reactions, the answer to this question is option C.
When the cell potential is positive. A redox reaction is spontaneous when the cell potential is positive.The cell potential is the measure of the driving force of the chemical reaction occurring in the electrochemical cell. In an electrochemical cell, a redox reaction occurs, which leads to the production of an electric potential.
If this potential is positive, then the redox reaction is considered spontaneous. However, if the potential is negative, then the reaction is non-spontaneous.In general, a redox reaction is spontaneous if the potential difference between the two electrodes of the cell is positive. This means that the reaction will occur spontaneously without any external energy input.
Thus, the correct option is C.
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?
Which statement about energy transfer in a wave is ture
For a particular reaction at 235.8 °C, ΔG=−936.92 kJ/mol , and ΔS=513.79 J/(mol⋅K) . Calculate ΔG for this reaction at −9.9 °C.
Answer:
-138.9 kJ/mol
Explanation:
Step 1: Convert 235.8°C to the Kelvin scale
We will use the following expression.
K = °C + 273.15 = 235.8°C + 273.15 = 509.0 K
Step 2: Calculate the standard enthalpy of reaction (ΔH°)
We will use the following expression.
ΔG° = ΔH° - T.ΔS°
ΔH° = ΔG° / T.ΔS°
ΔH° = (-936.92kJ/mol) / 509.0K × 0.51379 kJ/mol.K
ΔH° = -3.583 kJ (for 1 mole of balanced reaction)
Step 3: Convert -9.9°C to the Kelvin scale
K = °C + 273.15 = -9.9°C + 273.15 = 263.3 K
Step 4: Calculate ΔG° at 263.3 K
ΔG° = ΔH° - T.ΔS°
ΔG° = -3.583 kJ/mol - 263.3 K × 0.51379 kJ/mol.K
ΔG° = -138.9 kJ/mol
How many cups are in five gallons?
Answer:
In 5 US liquid gallons, there are 80 cups.
Explanation:
To get from gallons to cups, just multiply the amount of gallons you have by 16.
Any process with a negative change in enthalpy and a positive change in entropy will be:_______.
a. spontaneous
b. nonspontaneous
c. spontaneous at high temperatures
d. spontanteous at low temperatures
Answer:
a. spontaneous
Explanation:
Hello,
In this case, since the Gibbs free energy is a metric that allows us to know whether a chemical reaction is spontaneous (Gibbs free energy less than 0) or nonspontaneous (Gibbs free energy greater than 0) we can mathematically define it as:
[tex]\Delta G=\Delta H-T\Delta S[/tex]
Thus, if the enthalpy is negative and the entropy is negative, the subtraction become always negative, for which the Gibbs free energy is negative as well, therefore, based on the aforementioned, any process with a negative change in enthalpy and a positive change in entropy will be: a. spontaneous.
Best regards.
How many milliliters of 7.10 M hydrobromic acid solution should be used to prepare 5.50 L of 0.400 M HBr
Answer:
310 mL
Explanation:
Step 1: Given data
Initial concentration (C₁): 7.10 MInitial volume (V₁): ?Final concentration (C₂): 0.400 MFinal volume (V₂): 5.50 LStep 2: Calculate the initial volume
We have a concentrated HBr solution and we want to prepare a diluted one. We can do so using the dilution rule.
C₁ × V₁ = C₂ × V₂
V₁ = C₂ × V₂ / C₁
V₁ = 0.400 M × 5.50 L / 7.10 M
V₁ = 0.310 L = 310 mL
a 82.6 L sample of gas exerts 350.8 mm hg pressure at 134.6 c°. what valine does the gas have at 736.4 mm hg and 42.8 c°
a. 30.5
b 4.13
c. 12.5
d. 134
need help ASAP
Answer:
nfururhrj waltz quiz amora7ersgdsYsdi6 whiz 53
96rduttie
To calculate changes in concentration for a system not at equilibrium, the first step is to determine the direction the reaction will proceed. To do so, we calculate Q and compare it to the equilibrium concentration, K. We can then determine that a reaction will shift to the right if:__________
Answer:
We can then determine that a reaction will shift to the right if Q<K
Explanation:
Comparing Q with K allows to find out the status and evolution of the system:
If the reaction quotient is equal to the equilibrium constant, Qc = Kc, the system has reached chemical equilibrium. If the reaction quotient is greater than the equilibrium constant, Qc> Kc, the system is not in equilibrium and will evolve spontaneously, decreasing the value of Qc until it equals the equilibrium constant. In this way, the concentrations of the products will decrease and the concentrations of the reagents will increase. In other words, the reverse reaction is favored to achieve equilibrium. Then the system will evolve to the left (ie products will be consumed and more reagents will be formed).If the reaction quotient is less than the equilibrium constant, Qc <Kc, the system is not in equilibrium and will evolve spontaneously increasing the value of Qc until it equals the equilibrium constant. This implies that the concentrations of the products will increase and those of the reagents will decrease. In other words, to achieve balance, direct reaction is favored. Then the reaction will shift to the right, that is, reagents will be consumed and more products will be formed.In this case, we can then determine that a reaction will shift to the right if Q<K
1A. A strontium hydroxide solution is prepared by dissolving 10.45 g of Sr(OH)2 in water to make 41.00 mL of solution. What is the molarity of this solution?
1B. Next the strontium hydroxide solution prepared in part (a) is used to titrate a nitric acid solution of unknown concentration. Write a balanced chemical equation to represent the reaction between strontium hydroxide and nitric acid solutions.
1C. If 23.9 mL of the strontium hydroxide solution was needed to neutralize a 31.5 mL aliquot of the nitric acid solution, what is the concentration (molarity) of the acid?
Answer:
1. 0.00352 M
2. 2HNO3(aq) + Sr(OH)2(aq) -----> Sr(NO3)2(aq) + 2H2O(l)
3. 0.00534 M
Explanation:
1.
Mass of strontium hydroxide= 10.45 g
Volume of solution = 41.00 ml
Number of moles = mass of Sr(OH)2/molar mass of Sr(OH)2 = 10.45g/121.63 g/mol= 0.0859 moles
Molarity= number of moles × volume = 0.0859 ×41/1000 = 0.00352 M
2.
2HNO3(aq) + Sr(OH)2(aq) -----> Sr(NO3)2(aq) + 2H2O(l)
3.
Concentration of acid CA= the unknown
Volume of acid VA= 31.5 ml
Concentration of base CB= 0.00352 M
Volume of base VB= 23.9 ml
Number of moles of acid NA= 2
Number of moles of base NB= 1
From;
CAVA/CBVB = NA/NB
CAVANB= CBVBNA
CA= CBVBNA/VANB
CA= 0.00352 × 23.9 ×2/31.5 ×1
CA= 0.00534 M
A. The molarity of the Sr(OH)₂ solution is 2.09 M
B. The balanced equation for the reaction is
2HNO₃ + Sr(OH)₂ —> Sr(NO₃)₂ + 2H₂O
C. The molarity of the acid, HNO₃ is 3.17 M
A. Determination of the molarity of the Sr(OH)₂ solution
We'll begin by calculating the number of mole in 10.45 g of Sr(OH)₂Mass of Sr(OH)₂ = 10.45 g
Molar mass of Sr(OH)₂ = 88 + 2(16 + 1) = 122 g/mol
Mole of Sr(OH)₂ =?Mole = mass / molar mass
Mole of Sr(OH)₂ = 10.45 / 122
Mole of Sr(OH)₂ = 0.0857 mole Finally, we shall determine the molarity of Sr(OH)₂Mole of Sr(OH)₂ = 0.0857 mole
Volume = 41 mL = 41 / 1000 = 0.041 L
Molarity of Sr(OH)₂ =?Molarity = mole / Volume
Molarity of Sr(OH)₂ = 0.0857 / 0.041
Molarity of Sr(OH)₂ = 2.09 MB. The balanced equation for the reaction.
2HNO₃ + Sr(OH)₂ —> Sr(NO₃)₂ + 2H₂OC. Determination of the molarity of the acid, HNO₃.
From the balanced equation above,
The mole ratio of the acid, HNO₃ (nA) = 2
The mole ratio of the base, Sr(OH)₂ (nB) = 1
From the question given above,
Volume of base, Sr(OH)₂ (Vb) = 23.9 mL
Molarity of base, Sr(OH)₂ (Mb) = 2.09 M
Volume of acid, HNO₃ (Va) = 31.5 mL
Molarity of acid, HNO₃ (Ma) =?MaVa / MbVb = nA/nB
(Ma × 31.5) / (2.09 × 23.9) = 2
(Ma × 31.5) / 49.951 = 2
Cross multiply
Ma × 31.5 = 49.951 × 2
Ma × 31.5 = 99.902
Divide both side by 31.5
Ma = 99.902 / 31.5
Ma = 3.17 MThus, molarity of the acid, HNO₃ is 3.17 M
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Which part of an atom is mostly empty space?
A. nucleus
B. proton cloud
C. electron cloud
D. neutron
Answer:
C. Electron cloud
the electron is around 1/2000 times the size of the proton.
If you imagine the proton a a marble in the middle of a football field, the electrons will revolve around the last row
describe cold blooded animal.also some five example.
Answer:
Cold blooded animals are animals which stay in water
Explanation:
Examples are;snakes,tortoises,turtles,crocodiles,alligators