Answers
Explanation:
As it happens, early human embryos do have slits in their necks that look like gills. This is almost certainly because humans and fish share some DNA and a common ancestor, not because we go though a “fish stage” when in our mothers' wombs as part of our development towards biological perfection
Ancestral characters are often, but not always, preserved in an organism’s development. For example, both chick and human embryos go through a stage where they have slits and arches in their necks like the gill slits and gill arches of fish. These structures are not gills and do not develop into gills in chicks and humans, but the fact that they are so similar to gill structures in fish at this point in development supports the idea that chicks and humans share a common ancestor with fish. Thus, developmental characters, along with other lines of evidence, can be used for constructing phylogenies.

Related Questions
What does a change in the entropy of a system indicate?
A.
That the disorder of the system has changed
B.
That the equilibrium position has changed
C.
That the energy of the system has changed
D.
That the activation energy has changed
Answers
A change in the entropy of a system indicate that the disorder of the system has changed. Option A
What is a change in entropy?A change in entropy indicates is a measure of the disorder, or randomness, in a system.
An increased value of entropy means more disorder, and a decreased value of entropy means less disorder.
These changes in entropy occur spontaneously
Thus, a change in the entropy of a system indicate that the disorder of the system has changed. Option A
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A sample of an unknown compound is vaporized at 160 c . The gas produced has a volume of 2330 ml at a pressure of 1.00 atm ,and it weighs 2.10 g
Round answer to 3 significants digits
Answers
The molar mass is 3230.8 g/mol
How to determine the valueFirst, we need to know that the formula for the general gas law is represented as;
PV = nRT
such that the parameters are;
P is the pressureV is the volumen is the number of molesR is the gas constantT is the temperatureSubstitute the values
1 × 2.33 = n × 8.314 × 433.15
Multiply the values, we get;
n = 2.33/ 8.314 × 433.15
Divide the values
n = 6.5 × 10⁻⁴ moles
But, number of moles = mass/molar mass
Molar mass = 2.10/ 6.5 × 10⁻⁴
Molar mass = 3230.8 g/mol
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How should scientists set up the control group in this experiment?
Answers
Answer:
Please show a file so I can answer your question or tell me which experiment.
Explanation:
Definition:The control group (sometimes called a comparison group) is used in an experiment as a way to ensure that your experiment actually works. It's a way to make sure that the treatment you are giving is causing the experimental results, and not something outside the experiment.
help I can't find the answers
Answers
Answer:
baking soda - sodium hydrogen carbonate
bleach (liquid) - sodium hypochlorite
bleach (solid)- sodium hypochlorite
borax- sodium tetraborate decahydrate
brimstone- magnesium sulfate heptahydrate (sulfur)
cream of tartar- potassium hydrogen tartrate
Epsom salt- magnesium sulfate
Freon- Dichlorodifluoromethane
galena- gray lead sulfide
grain alcohol- ethanol
graphite- carbon silicon family
gypsum- calcium sulfate
hypo- sodium thiosulfate
laughing gas- nitrous oxide
lime- calcium hydroxide
limestone- calcium hydroxide
lye- sodium hydroxide
(i'll finish the rest later)
Explanation:
species evolve at different rates. for example, bacteria are unlikely to become extinct because they adapt more quickly than mammals to environmental changes. which pf the following best explains this difference
A: Bacteria reproduce more rapidly, allowing species to evolve more quickly
B:Bacterial populations are more isolated, permitting increases in genetic variability
C:certain bacteria grow more steadily over time, giving an evolutionary advantage over mammals
D: Individual bacteria have the same genes, providing opportunities for increased biodiversity in one population.
Answers
Answer:A
Explanation:
Species evolve at different rates. for example, bacteria are unlikely to become extinct because they adapt more quickly than mammals to environmental changes. Bacteria reproduce more rapidly, allowing species to evolve more quickly best explains this difference. Therefore, option A is correct.
What allows bacteria to evolve so quickly ?Bacterial species evolve quickly because of their large populations, which provide numerous opportunities for mutations, and because they readily exchange genetic information, even between species. Some of this genetic diversity influences drug sensitivity or resistance, providing material for Darwinian selection.
Bacteria are among the world's fastest reproducing organisms, doubling every 4 to 20 minutes. Some pathogenic strains of E. coli grow quickly.
Bacterial populations evolve antibiotic resistance so quickly due to their fast generation times, large population sizes, and unique gene acquisition methods. These are some of the reasons bacteria have been so successful in evolution.
Thus, option A is correct.
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Which group of pair with a group 5 non-metal, such as nitrogen, in a 1:1 ratio based on trends in valence electrons?
A. Group 1A or 1
B. Group 2A or 2
C. Group 3A or 13
D. Group 6A or 16
Answers
Based on valence electron trends, the correct answer is C. Group 3A or 13.
Based on trends in valence electrons, the group of pairs with a group 5 non-metal, such as nitrogen (N), in a 1:1 ratio is Group 3A or 13. Group 5 non-metals have 5 valence electrons, and they tend to form compounds by either gaining 3 electrons to achieve a stable octet or by sharing 3 electrons in covalent bonds.
Group 1A or 1 elements, such as hydrogen (H) and lithium (Li), have only 1 valence electron. They would need to gain 4 additional electrons to achieve a stable octet, which is energetically unfavorable.
Group 2A or 2 elements, such as beryllium (Be) and magnesium (Mg), have 2 valence electrons. They would need to gain 3 additional electrons to achieve a stable octet, which is also energetically unfavorable.
Group 6A or 16 elements, such as oxygen (O) and sulfur (S), have 6 valence electrons. They would need to gain only 1 additional electron to achieve a stable octet, making them more likely to form a 2:1 ratio with a group 5 non-metal.
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What is the correct Lewis structure for Group 5A element, Arsenic?
Answers
The correct Lewis structure for Group 5A element, Arsenic is structure A.
What are Lewis structure?
A very simplified representation of a molecule's valence shell electrons is known as a Lewis structure. The octet rule, which states that atoms share electrons such that each has eight in its outer shell, is the foundation of a Lewis structure. Lewis structures are used to examine and comprehend chemical bonds and atomic structures.
Arsenic is an element that, as far as we are aware, belongs to group 15 and has a total of 5 valence electrons. The structure shows the five covalent bonds that bind arsenic to one another chemically. So, once one electron is filled in isolation, pairing takes place.
Arsenic's true Lewis structure, thus, is structure A for Group 5A element.
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Plz help me well mark brainliest if correct!!
Answers
Answer:
A
Explanation:
Waxing means getting bigger.
Waning is.. you guessed it... the exact opposite.
Answer:
a
Explanation:
..........................
A glass of cold water starts at 0.3 degrees Celsius. Over the course of 9 minutes the water warms up to 9.2 degrees Celsius. At what rate is the water warming? answer without units, round to 2 decimal places.
this is science, please answer correctly
Answers
Explanation:
http://web.abo.fi/fak/tkf/at/Courses/Basics_in_Process_Design/C&R%20vol6%20answers/Chapter12.pdf
Please help me with this
If somebody posts b.u.l.l.s.h.i.t. answers, please report them!!
Answers
Answer:
where is the question
Explanation:
A chemist working for Udensi industries wants to create a new ink for tattoos and cosmetics. Determine the theoretical yield of iron (ll) sulfide if the chemist uses 22.5 grams of iron ? Type of rxn : AD , SR, DR , D Type of calculation : mol to mol ; mol to mass ; mass to mols mass to mass Fe S8--> Fes
Answers
Answer:
35.36 g
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
8Fe + S₈ —> 8FeS
Next, we shall determine the mass of Fe that reacted and the mass of FeS produced from the balanced equation. This can be obtained as follow:
Molar mass of Fe = 56 g/mol
Mass of Fe from the balanced equation = 8 × 56 = 448 g
Molar mass of FeS = 56 + 32 = 88 g/mol
Mass of FeS from the balanced equation = 8 × 88 = 704 g
SUMMARY:
From the balanced equation above,
448 g of Fe reacted to produce 704 g of FeS.
Finally, we shall determine the theoretical yield of FeS as follow:
From the balanced equation above,
448 g of Fe reacted to produce 704 g of FeS.
Therefore, 22.5 g of Fe will react to produce = (22.5 × 704)/448 = 35.36 g of FeS.
Thus, the theoretical yield of FeS is 35.36 g
Which tool was most likely used in a procedure if the lab report shows that approximately 300 mL of water was used?
a volumetric flask
a graduated cylinder
a pipette
a beaker
apparently not a graduated cylinder
Answers
Answer:
Beaker
Explanation:
just took on edge 2021
A volumetric flask tool is likely used in a procedure if the lab report shows that approximately 300 mL of water was used. Hence option A is correct.
What is an experiment?The experiment name is titration. In this process of chemical analysis in which some quantity of some constituent of a sample is determined by adding to the measured sample exactly the known quantity of another substance.
Titration types: Acid-base titration, redox titration, precipitation titration, complexometric titration.
Uses:
Volumetric glass: it is used to make a solution to a known volume.Graduated cylinder: it is used to measure the volumes of liquidsPipette: it is used to move a small amount of liquid from one place to another.Beaker: it is used as a reaction container or to hold liquid.A volumetric flask tool likely used in a procedure if the lab report shows that approximately 300 mL of water was used. Hence option A is correct.
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What is the molarity of a saline solution that contains 0.900g NaCl (58.44 g/mol) dissolved in 100.0 mL of solution?
Answers
Hey there!:
Molar mass NaCl = 58.44 g/mol
Number of moles = mass of solute / molar mas
Number of moles = 0.900 / 58.44
Number of moles = 0.0154 moles of NaCl
Volume in liters of solution :
100.0 mL / 1000 => 0.1 L
Therefore:
Molarity = number of moles / volume in liters
Molarity = 0.0154 / 0.1
Molarity = 0.154 M
Hope this helps!
1) Describe enthalpy and the role specific heat plays in the formula. 2) Explain the significance of the sign of the enthalpy value (+ or -) . Provide a specific example. 3) Explain Collision theory and describe the two factors required for a chemical reaction to occur. 4) Connect each of these circumstances to the rate of a reaction. Explain how the change in circumstances could be implemented in a lab and describe the predicted outcome: - Increased temperature - Decreased solution concentration - Increased surface area - Speeding up the reaction without being involved in the reaction. 5) Analyze Le Chatelier’s principle. 6) Based on this theory, what is the overriding guide to predicting outcomes when changes are imposed upon a reaction. What is the impact on equilibrium?
Answers
Explanation:
5) Le Chatelier's principle says, when in a reversible reaction any of the concentration or temperature or pressure are changed, then the equilibrium shifts such a way to nullify the changes occurred. (hope you get it)
6) 1.change in concentrationR ======= P
if concentration of reactant R is increased then eqm shifts towards the one with lower concentration ,that is product P.
forward direction is favoured.
2.Change in temperatureif the above's reaction is endothermic, that is temp of product is low. So increasing temperature in such case reaction goes towards product.
forward direction is favoured.
If reaction is exothermic ,temp of reactant is more. So increasing temperature in such case, reaction goes towards reactants.
forward direction is favoured
........ plz brainliest my answer I definitely write you the complete explanation asap!
What is the concentration of potassium ions in 153 mLof a 1.25 M K3PO4 solution
Answers
Answer:
\(=3.75M\)
Explanation:
Hello,
In this case, given the concentration of the potassium phosphate, we can compute the concentration of potassium ions by noticing that in one mole of salt, three moles of potassium ions are present. Moreover, since the molar units (mol/L) are in terms of potassium phosphate we should apply the following mole-mole relationship:
\(1.25\frac{molK_3PO_4}{L}*\frac{3molK^+}{1molK_3PO_4} \\\\3.75\frac{molK^+}{L}=3.75M\)
Best regards.
Answer:
The concentration of potassium (K⁺) ions in the solution of 153 mL of 1.25 M K₃PO₄ is 3.75 moles
Explanation:
The parameters given are;
Volume of K₃PO₄ = 153 mL = 0.153 L
Concentration of K₃PO₄ = 1.25 M
The ionization of K₃PO₄ is as follows;
K₃PO₄ ⇄ 3·K⁺ (aq) + PO₄³⁻ (aq)
Therefore, 1 mole of K₃PO₄, produces 3 moles of potassium (K⁺) ions
Hence, the number of moles of K₃PO₄ in 153 mL of 1.25 M K₃PO₄ is found as follows;
153 mL of 1.25 M K₃PO₄ = 0.153 L of 1.25 M K₃PO₄
The number of moles present in 0.153 L of 1.25 M K₃PO₄ = 0.153 × 1.25 moles
The number of moles present in 0.153 L of 1.25 M K₃PO₄ = 0.19125 moles of K₃PO₄
Since 1 mole of K₃PO₄ produces 3 moles of potassium (K⁺) ions we have;
0.19125 moles of K₃PO₄ will produce, 3 × 0.19125 moles of potassium (K⁺) ions which gives;
0.19125 moles of K₃PO₄ will produce 0.57375 moles of potassium (K⁺) ions
Therefore, the amount of moles of potassium (K⁺) ions in 153 mL = 0.57375 moles
The the amount of moles of potassium (K⁺) ions in 1 L (1000 mL) = (1000/153) × 0.57375 moles
The the amount of moles of potassium (K⁺) ions in 1 L = 3.75 moles
Therefore, the concentration of potassium (K⁺) ions in the solution of 153 mL of 1.25 M K₃PO₄ = 3.75 moles.
Ca and F what are the name of the ionic compounds
Answers
Answer:
Calcium flouride?
Explanation:
Quite self explanatory
Give an example of a microscope problem that could be prevented by cleaning
Answers
germs can spread from person to person, especially since it’s so close to eyes and common high touch areas.
What is the pH of a solution with an [H+] of (a) 5.4 x 10-10, (b) 4.3 x 10-5, (c) 5.4 x 10-7?
Answers
Answer:
a. 9.2
b. 4.4
c. 6.3
Explanation:
In order to calculate the pH of each solution, we will use the definition of pH.
pH = -log [H⁺]
(a) [H⁺] = 5.4 × 10⁻¹⁰ M
pH = -log [H⁺] = -log 5.4 × 10⁻¹⁰ = 9.2
Since pH > 7, the solution is basic.
(b) [H⁺] = 4.3 × 10⁻⁵ M
pH = -log [H⁺] = -log 4.3 × 10⁻⁵ = 4.4
Since pH < 7, the solution is acid.
(c) [H⁺] = 5.4 × 10⁻⁷ M
pH = -log [H⁺] = -log 5.4 × 10⁻⁷ = 6.3
Since pH < 7, the solution is acid.
The helium tank has a pressure of 650 torr at 25 degree celsius what will be the pressure if the temperature is tripled?
pa help po
Answers
The helium tank has a pressure of 650 torr at 25 degree Celsius and when the temperature is tripled, the pressure will be approximately 1945.71 torr
To find the new pressure when the temperature is tripled, we can use the ideal gas law, which states that the pressure of a gas is directly proportional to its temperature when the volume and the number of particles remain constant. The ideal gas law is given by the equation:
PV = nRT
Where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.
First, we need to convert the initial temperature of 25 degrees Celsius to Kelvin. Adding 273.15 to the Celsius temperature gives us 298.15 K.
Let's assume that the volume, number of moles, and the gas constant remain constant.
If the temperature is tripled, the new temperature would be 3 times the initial temperature, which is 3 * 298.15 K = 894.45 K.
Now, we can set up a proportion to find the new pressure:
P1 / T1 = P2 / T2
Solving for P2 (the new pressure), we get:
P2 = (P1 * T2) / T1
Plugging in the values, we have:
P2 = (650 torr * 894.45 K) / 298.15 K
Calculating this expression, we find:
P2 ≈ 1945.71 torr
Therefore, when the temperature is tripled, the pressure will be approximately 1945.71 torr.
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Arrange: Click Next element to select carbon. Add a second electron to the first 2p orbital.Click Check. What feedback is given?6. Rearrange: Hund’s rule states that electrons will occupy an empty orbital when it is available in that subshell. Rearrange the electrons within the 2p subshell and click Check.Is the configuration correct now?Show the correct configuration in the boxes at right:
Answers
Answer:
See explanation
Explanation:
The correct electronic configuration for carbon is;
1s2 2s2 2px1 2py1 2pz0
Carbon has six electrons in its outermost shell. According to Hund's rule, electrons will occupy all the empty orbitals when they are available in that subshell.
Hence, if you attempt to add a second electron the the first 2p orbital (2px), the arrangement of electrons will be flagged as incorrect. The other 2p electron must be added to the second 2p (2py) orbital.
A sample contains 0.1895 g of salt per 50 g of seawater. What is its salinity?
Answers
50 g mean 100% 0,1895 mean x% cross multiplie and calcule the x value x = 0,1895*100/50 = ?%
0.450 moles of oxygen gas is subjected to a pressure of 3.00 atm and 75 oC.
What is it's volume (in Liters)?
Answers
Use this formula PV=nRT
Rearrange formula , question want V ,so
V=nRT/P
given
P= 3.00 atm
n=0.450 moles
R is ideal gas constant = 0.08206 L atm mol-¹K-¹
T in Kelvin so , (75 + 273)= 348 Kelvin (K)
Then insert all this information given with that rearranged formula V=nRT/P
so, V= (0.45)(0.08206)(348) / 3.00 = 4.284 LA chunk of coal has a substantial amount of chemical potential energy.This image is courtesy of Oak Ridge National Laboratory.If released, the chemical potential energy will cause the coal atoms and molecules to vibrate violently, and this internal kinetic energy can be transferred to other nearby objects.Which of these is the best way to transform this chemical potential energy into internal kinetic energy? A. burn the coal B. drop the coal from a great height C. submerge the coal in water D. roll the coal down a hill
Answers
Answer:
Burn the coal!!!!
Explanation:
Answer :
Burn it
Explanation:
Kinetic energy is the energy of motion. Sometimes, this motion is internal.
When coal is heated, the atoms and molecules inside of the coal can gain a large amount of kinetic energy. This is experienced as heat.
The best way to release all of a chunk of coal's internal kinetic energy is to burn it.
2,3,7,9-tetramethyl-5-(1-metilbutil)decano
Answers
The IUPAC name for 2,3,7,9-tetramethyl-5-(1-methylbutyl)decanoic acid is 2,3,7,9-tetramethyl-5-(1-methylbutyl)decanoic acid. It is a carboxylic acid with a molecular formula of C20H40O2 and a molecular mass of 312.54 g/mol. The compound has a melting point range of 70-75°C.
2,3,7,9-tetramethyl-5-(1-methylbutyl)decanoic acid contains a carboxyl group (-COOH), which is the functional group responsible for its acidic properties and solubility in water. The presence of the carboxyl group makes the compound more polar than similar molecules, enhancing its water solubility. Carboxylic acids are also known for their reactivity with bases and ability to undergo esterification reactions.
In summary, 2,3,7,9-tetramethyl-5-(1-methylbutyl)decanoic acid is a carboxylic acid with a unique molecular structure. Its IUPAC name describes the positions and nature of the substituent groups. The presence of the carboxyl group contributes to its polarity, water solubility, acidity, and reactivity with bases and esterification reactions. The compound's characteristics are significant in understanding its properties and potential applications in various chemical reactions and processes.
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Which statement is true about the ionic size of the elements in a group as one moves from bottom to top in that group? Responses Ionic size decreases from bottom to top within the group. Ionic size decreases from bottom to top within the group. Ionic size does not vary in any predictable way within the group. Ionic size does not vary in any predictable way within the group. Ionic size stays the same within the group. Ionic size stays the same within the group. Ionic size increases from bottom to top within the group.
Answers
The statement that is true about the ionic size of the elements in a group as one moves from bottom to top in that group is as follows: Ionic size decreases from bottom to top within the group (option A).
What is periodic table?Periodic table is a tabular chart of the chemical elements according to their atomic numbers so that elements with similar properties are in the same group.
Ionic size increases from top to bottom down a group of elements in the periodic table. From left to right across a period, the ionic size decreases as long as you are comparing all metals or all nonmetals.
In a periodic table while moving down in a group, atoms add an extra shell (number of electrons) due to which the ionic size of elements increases down a group i.e. from top to bottom.
This means that from bottom to top, the ionic size of the elements in the group will decrease.
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PLEASE ANSWER QUICKLY!!!!
2KI (aq) + Cl₂(g) → 2KCl(aq) + 1₂(g)
What volume of 12 gas forms when
21 L Cl2 react at STP?
[?] L 12
Answers
The volume of 12 gas forms when 21 L Cl2 react at STP is 21 L.
To determine the volume of 12 gas (I assume you mean I2 gas) formed when 21 L of Cl2 reacts at STP (standard temperature and pressure), we need to use the ideal gas law equation.
The ideal gas law equation is given by:
PV = nRT
Where:
P = pressure
V = volume
n = number of moles
R = ideal gas constant
T = temperature
At STP, the pressure is 1 atm, and the temperature is 273.15 K.
From the balanced equation, we can see that the molar ratio between Cl2 and I2 is 1:1. So, if 21 L of Cl2 reacts, it will produce an equal volume of I2 gas.
Given that the volume of Cl2 is 21 L, we can assume the volume of I2 gas formed will also be 21 L.
Therefore, the volume of I2 gas formed is 21 L.
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Which of the following changes would increase the pressure of a gas in a closed
container?
a) More gas is added
b) Temperature is increased
c) The container's size is increased
d) Part of the gas is removed
e) Temperature is decreased
f) The container's size is decreased
Answers
Answer:
a) More gas is added
b) Temperature is increased
f) The container's size is decreased
Explanation:
For an ideal gas, pressure is jointly proportional to temperature and the quantity of gas, and inversely proportional to the volume. Then pressure will increase for ...
a) More gas is added
b) Temperature is increased
f) The container's size is decreased
6th Grade Science question on Mass, Volume, and Density!! I've tried and tried and I can't figure it out!
Answers
According to the law of conservation of mass, how much zinc was produced if Calcium = 25 g, Zinc Carbonate = 125 g, and Calcium Carbonate = 95 g.
HELPP
Answers
All the balanced chemical equations obey the law of conservation of mass. The numbers which are used to balance the chemical equation are called the coefficients. So here the mass of zinc is 55 g.
According to the law of conservation of mass, the mass can neither be created nor be destroyed but it can be converted from one form to another. The reactants appear on the left hand side and the products appear on the right hand side.
The amount of products is equal to the amount of reactants according to the law of conservation of mass.
25 + 125 = 95 + Zn
Zn = 55 g
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How many moles of aluminum ions al3+ are present in 0.42 mol of al2so43
Answers
There are 0.84 moles of aluminum ions (Al3+) present in 0.42 mol of Al2(SO4)3.
To determine the number of moles of aluminum ions (Al3+) present in 0.42 mol of Al2(SO4)3, we need to consider the stoichiometry of the compound.
The formula of aluminum sulfate (Al2(SO4)3) indicates that for every 1 mole of the compound, there are 2 moles of aluminum ions (Al3+). This means that the mole ratio of Al3+ to Al2(SO4)3 is 2:1.
Given that we have 0.42 mol of Al2(SO4)3, we can calculate the moles of Al3+ as follows:
Moles of Al3+ = 0.42 mol Al2(SO4)3 x (2 mol Al3+ / 1 mol Al2(SO4)3)
Moles of Al3+ = 0.42 mol Al2(SO4)3 x 2
Moles of Al3+ = 0.84 mol Al3+
Therefore, there are 0.84 moles of aluminum ions (Al3+) present in 0.42 mol of Al2(SO4)3.
It's important to note that the stoichiometry of the compound determines the mole ratio between the different species involved in the chemical formula. In this case, the 2:1 ratio of Al3+ to Al2(SO4)3 allows us to determine the number of moles of Al3+ based on the given amount of Al2(SO4)3.
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