plssss help me I only have 10 mins.
Answer:
Scientists must collect accurate information that allows them to make evolutionary connections among organisms. Similar to detective work, scientists must use evidence to uncover the facts. In the case of phylogeny, evolutionary investigations focus on two types of evidence: morphologic (form and function) and genetic.
Explanation:
This what I think
Answer:
C
Explanation:
Just like a Alligator or Croc, they evolved from the dinosuar's. The scientest KNOW THIs mainly because they have compared the fossil's of a crocidile THEN and a corcidile NOW (Just a example)
Hope this helps and pls mark brainlest!
1.Explain why the reactivity of group 7 decreases as you move down the group. Try to use the sentence starters here: When group 7 elements react, their atoms….
As you move down the group, the outer shells get…
Therefore the force of attraction between the shells and the nucleus is….
This makes attracting an extra electron…
Consequently, reactivity…
Answer: The reactivity of group 7 decreases as we move down the group because:
Explanation:
The elements of group 7 that is fluorine to iodine. The halogens are non metals and they react with metals to gain electrons. The metals loose electrons and the non metal gains it.
As we move down the group the atomic radius gets bigger( more electron and more proton) and as a result the outer shells move further away from the nucleus.
There is more distance between the negatively charged electrons and positively charged nucleus.
Therefore the force of attraction between the shells and nucleus is lesser or weaker.
This makes attracting an extra electron from metals very difficult which results in weaker reaction.
Consequently, the reactivity decreases as we move down the group 7
What kinds of shapes can carbon based molecules form?
Answer:
Straight chains, branched chain and rings.
Explanation:
Hope this helps :)
Answer/Explanation:
Carbon based molecules tend to form in chain like patterns. So, carbon molecules could/would form a chain that branches out, a chain that travels in a straight or constant direction, and a chain that connects into a loop style.
If pure argon gas were mixed with pure hydrogen gas would the two elements react with each other?
Answer:
No, the two substances will not react with each other
Explanation:
We already know that argon belongs to group 18 in the periodic table. Members of this group are commonly referred to as noble gases. So, we can say that argon is a noble gas.
One characteristic of noble gases is that they possess a filled outermost shell, they have a complete octet of electrons. As a result of this, they hardly participate in chemical reactions since they have already attained the stability that arises from having a complete octet of electrons.
Hence, argon will not react with hydrogen.
A magnet was placed near a pile that contained both iron and sulfur. The magnet was moved gradually closer to the pile. As it neared the pile, the magnet started attracting small pieces of iron from the pile. Which of these statements best describes the contents of the pile?
The question is incomplete, the complete question is;
A magnet was placed near a pile that contained both iron and sulfur. The magnet was moved gradually closer to the pile. As it neared the pile, the magnet started attracting small pieces of iron from the pile. Which of these statements best describes the contents of the pile?
F. It is a homogeneous mixture of iron and sulfur. G. It is a heterogeneous mixture of iron and sulfur. H. It is a compound that contains both iron and sulfur. I. It is a compound that can be separated by magnetism.
Answer:
G. It is a heterogeneous mixture of iron and sulfur.
Explanation:
A heterogeneous mixture is one that does not have a uniform composition throughout.
We must recall that a mixture is any combination of substances that do not chemically react together and are separable by physical means.
Having said this, it is clear that I can separate the iron from sulphur by simple magnetic (physical) means. Hence, it is a heterogeneous mixture of iron and sulfur.
Answer:
It is a heterogeneous mixture of iron and sulfur.
Explanation:
Most chemical reactions release energy or are exothermic. However, some reactions, such as some decompositions, absorb energy. These reactions can be best explained by which of these? A) Energy is destroyed in the chemical reaction. B) The products have less energy stored in their chemical bonds. C) The products have more energy stored in their chemical bonds. D) The reactants have the same energy stored in their chemical bonds.
Answer:
C) The products have more energy stored in their chemical bonds.
Explanation:
In such reactions that absorb energy, the products have more energy stored in their chemical bonds.
For endothermic changes, heat is absorbed from the surrounding hence the surrounding becomes colder at the end of the changes.
The heat energy level of the products is higher than that of the reactants.
Exothermic reactions releases heat to the surroundings. The sum of heat contents of the products is less than that of the hat contents of the reactants. Examples of such processes are burning and dissolution.In the equation shown, what are the reactant(s)?
CsHot 0,7H2O+CO2
C=1
H = 8 H=2
0 = 2
C=3
O=3
wie
O C3H8
I need help fast...........
Answer:
I think its might be 1 because the ionic numbers for CA is +2 and for P its +3
What is the main function of the circulatory system?
A.
to eliminate waste from the body
B.
to distribute blood and nutrients throughout the body
C.
to support the body and allow movement
D.
to protect the body from infectious agents
can anyone help please ?
Answer:
The mass remains constant
Explanation:
Burning a wood is a chemical change which produces many products. According to the law of conservation of mass, matter is neither created nor destroyed in a chemical reaction.
This implies that the quantity of the product and reactants will remain the same before and after the reaction. When we write a balanced reaction equation for this process, we find that the number of moles are conserved and the same. So, this is replicated in the mass of the combining species and the product they form. For such a combination, mass is the same.Calculate the atomic mass of Copper if copper-63 is 69.17% abundant and Copper-65 is 30.83% abundant.
The atomic mass of Copper : 63.6166 amu
Further explanationGiven
Copper-63 is 69.17%
Copper-65 is 30.83%
Required
The atomic mass of Copper
Solution
The elements in nature have several types of isotopes
Atomic mass is the average atomic mass of all its isotopes
Mass atom X = mass isotope 1 . % + mass isotope 2.% ...
The atomic mass of Copper = 0.6917 x 63 + 0.3083 x 65
The atomic mass of Copper = 43.5771 + 20.0395
The atomic mass of Copper = 63.6166 amu
50 points please help
Answer:
The answer is 20mph
Hope this helps!!!
This question was posted more than a month ago so... I guess I'll take the points if you don't mind?
Compare and Contrast Fossil Fuel and
Sedimentary Rock Formation. (How are they similar and how are they different?)
Answer:
The small sediments that break off are eroded and deposited. The deposited sediment then goes through the processes of compaction and cementation to create sedimentary rock. Fossils from dead plants and animals are found in sedimentary rock. ... Over time, fossils are changed into fossil fuels.
Explanation:
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1A) What is the pH of a solution that was 0.75 M acetic acid? Ka for acetic acid is 1.7x10-5. (Note: 0.75 M is the initial concentration of acetic acid.)
Set up an ICE table for HC2H3O2(aq)+ H2O (l) C2H3O2-(aq) + H3O+(aq). Remember to cross out any solid or liquid compounds.
1B) Plug the “Equilibrium” (E) terms into the Ka expression:
It appears at first as though you will need to use the quadratic formula to solve for x because the numerator is squared and the denominator is not. However, there is a simple trick that can fix the algebra for these problems. Since Ka is so small, it can be assumed that x is also incredibly small. If x is very small, then 0.75-x will effectively remain 0.75. The “rule of 1000” says that as long as the initial concentration of the acid is at least 1000x larger than the Ka, you can make this assumption. 0.75 is 44,000x larger than 1.7x10-5, so the assumption is valid.
1C) Now that you know the equilibrium concentration of H+, calculate the pH.
Answer:
Answer:
4.921.
Explanation:
It is an acidic buffer solution;
∵ pH = pKa + log[salt]/[acid].
∴ pH = - log(1,8 x 10⁻⁵) + log[0.75/0.50] = 4.745 + 0.1761 = 4.921.
Explanation:
The pH of acid is between 0-7 on pH scale while for base pH range is from 7-14. pH is a unitless quantity. Therefore, the pH of a solution that was 0.75 M acetic acid is 4.921.
What is pH?pH is a measurement of amount of hydronium ion H₃O⁺ in a given sample. More the value of hydronium ion concentration, more will be the solution acidic.
On subtracting pH from 14, we get pOH which measures the concentration of hydroxide ion in a given solution. pH depend on the temperature. At room temperature pH scale is between 0 to 14. pH of neutral solution is 7.
pH of acetic acid= pKa + log[salt]/[acid]
pH of acetic acid = - log(1,8 x 10⁻⁵) + log[0.75/0.50]
= 4.745 + 0.1761
= 4.921
Therefore, the pH of a solution that was 0.75 M acetic acid is 4.921.
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If ice has a density of 0.92 g/ml what is the volume of 5,000g of ice?
Answer:
The answer is 5,434.8 cm^3
The volume corresponding to 5,000 g of ice with a density of 0.92 g/mL is 5.4 × 10³ mL.
The density (ρ) is an intrinsic property of matter. It is equal to the quotient between the mass (m) and the volume (V). If we have 5,000 g of ice with a density of 0.92 g/mL, its volume is:
[tex]\rho = m/V\\V = m/\rho = 5,000 g/(0.92 g/mL) = 5.4 \times 10^{3} mL[/tex]
The volume corresponding to 5,000 g of ice with a density of 0.92 g/mL is 5.4 × 10³ mL.
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Are electrons exchanged between ionic or covalent bonds
Answer:
Ionic bonds form when a nonmetal and a metal exchange electrons, while covalent bonds form when electrons are shared between two nonmetals.
Polonium-218 undergoes beta decay, converting a neutron into a proton. Then the daughter isotope undergoes another beta decay, again converting a neutron into a proton. Which equation correctly describes this process? Use the periodic table link from the tools bar to answer the question.
Answer: [tex]^{218}_{84}Po \rightarrow ^{218}_{85}At + ^{0}_{-1}e[/tex] is the correct equation for beta decay.
Explanation:
When a beta particle, that is, [tex]^{0}_{-1}e[/tex] is emitted in a radioactive decay then it is known as beta decay.
Therefore, beta decay of Polonium-218 is as follows.
[tex]^{218}_{84}Po \rightarrow ^{218}_{85}At + ^{0}_{-1}e[/tex]
Therefore, we can conclude that [tex]^{218}_{84}Po \rightarrow ^{218}_{85}At + ^{0}_{-1}e[/tex] is the correct equation for the given beta decay.
Answer:
A
Explanation:
The top dudes answer summed up.
Multiple Choice
Over time, a particular plant has developed a longer stamen. Which of the following is a possible advantage of having a longer stamen?
A. A longer stamen could ensure that an insect brushes against an anther and picks up pollen.
B. A longer stamen could ensure that the flower produces more nectar.
C. A longer stamen could ensure that pollen could reach the ovary and fertilize the egg.
D. A longer stamen could ensure that the developing flower is well protected.
Answer:
A) A longer stamen could ensure that an insect brushes against an anther and picks up pollen.
Explanation:
The stamen will provide easier access to the pollen.
Hope this helps :)
What are the horizontal rows on the periodic table numbered 1-7 called?
Answer: They're called Periods
periods of the periodic table
Please help i'm failing these are three different questions because I got no more points
How does the relative distance and length of year of outer planets compare with those of inner planets?
When compared with inner planets, the outer planets are relatively farther from the sun and have a longer year.
When compared with inner planets, the outer planets are relatively farther from the sun and have a shorter year.
The outer planets are relatively closer to the sun and have a longer year than the inner planets.
The outer planets are relatively closer to the sun and have a shorter year than the inner planets.
Which of the following is the correct order of these objects based on their distance from the sun, starting with the object closest to the sun?
Earth, asteroid belt, Saturn, Neptune, Mercury
Mercury, Earth, asteroid belt, Saturn, Neptune
Neptune, Mercury, asteroid belt, Earth, Saturn
Saturn, Neptune, Mercury, Earth, asteroid belt
What is a main difference between Earth and Jupiter?
Group of answer choices
Earth is an inner planet with a solid rock surface composition, while Jupiter is an outer planet with a gas surface composition.
Earth is an inner planet with a relatively long distance from the sun, while Jupiter is an outer planet with a relatively short distance from the sun.
Earth is an outer planet with a gas surface composition, while Jupiter is an inner planet with a solid rock surface composition.
Earth is an outer planet with a relatively short distance from the sun, while Jupiter is an inner planet with a long distance from the sun. PLEASE HELP
Answer:
This is just what I think Im sorry if it's wrong
Explanation:
The outer planets are relatively closer to the sun and have a longer year than the inner planets.
Mercury, Earth, asteroid belt, Saturn, Neptune
Earth is an inner planet with a solid rock surface composition, while Jupiter is an outer planet with a gas surface composition.
Of all chlorine atoms, 75.771% are chlorine-35. Chlorine-35 atoms have
a mass of 34.96885 amu. All other chlorine atoms are chlorine-37 and
these have a mass of 36.96590. Calculate the average atomic mass of
chlorine?
Relative and average atomic mass both describe properties of an element related to its different isotopes. Out of these two Relative atomic mas is more accurate. The average atomic mass is 35.5g.
What is mass?Mass defines the quantity of a substance. It is measured in gram or kilogram. Average mass is the mass of atoms of an element that are isotopes. It can be calculated by multiplying mass of a isotope to natural abundance of that isotope.
Average atomic mass = (mass of first isotope× percent abundance of first isotope)+(mass of second isotope× percent abundance of second isotope)
Substituting the given values
Average atomic mass=( 34.96885 amu ×75.771% )+( 36.96590 amu × 24.3%)
Average atomic mass=35.5g
Therefore, the average atomic mass of chlorine is 35.5g.
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A student places a small stone with a mass of 5 g into a graduated cylinder containing 50 mL of water. With the stone in the graduated cylinder, the water rises to 75 mL. What is the density of the stone? a. 0.07 g/mL b. 0.20 g/mL c. 5.00 g/mL d. 125.00 g/mL
Answer:
0.20 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
volume = final volume of water - initial volume of water
volume = 75 - 50 = 25 mL
From the question we have
[tex]density = \frac{5}{25} = \frac{1}{5} = 0.2 \\ [/tex]
We have the final answer as
0.20 g/mLHope this helps you
How do covalent bonds form neutral compounds?
Answer:
Covalent bonds form when electrons are shared between atoms and are attracted by the nuclei of both atoms.
PLEASSSSSSSSSE HELPPPPP
Answer:
3 g of H₂
Explanation:
The balanced equation for the reaction is given below:
Cr₂O₃ + 3H₂ —> 2Cr + 3H₂O
Next, we shall determine the masses of Cr₂O₃ and H₂ that reacted from the balanced equation. This can be obtained as follow:
Molar mass of Cr₂O₃ = (52×2) + (16×3)
= 104 + 48
= 152 g/mol
Mass of Cr₂O₃ from the balanced equation = 1 × 152 = 152 g
Molar mass of H₂ = 2 × 1 = 2 g/mol
Mass of H₂ from the balanced equation = 3 × 2 = 6 g
SUMMARY:
From the balanced equation above,
152 g of Cr₂O₃ reacted with 6 g of H₂
Finally, we shall determine the mass of H₂ needed to covert 76 g of Cr₂O₃. This can be obtained as follow:
From the balanced equation above,
152 g of Cr₂O₃ reacted with 6 g of H₂.
Therefore, 76 g of Cr₂O₃ will react with = (76 × 6) / 152 = 3 g of H₂
Thus, 3 g of H₂ is needed to convert 76 g of Cr₂O₃.
Where does the energy of a nuclear power plant come from?
A) the radiation released by unstable uranium isotopes
B) the heat energy released during nuclear fusion
C) the radiation released when hydrogen fuses into helium
D) the heat energy released during nuclear fission
Answer:
The heat energy released during nuclear fusion
The heat energy released during nuclear fusion. The correct option is D.
Thus, The Sun and other stars are powered by nuclear fusion reactions. A heavier nucleus is created when two light nuclei fuse together in a fusion reaction.
Because the mass of the resulting single nucleus is smaller than the combined mass of the two initial nuclei, the process produces energy. Remaining mass is converted to energy.
Why this happens is explained by Einstein's equation (E=mc2), which states in part that mass and energy can be transformed into one another. Fusion energy could be a significant source of energy generation if scientists can figure out how to use it in equipment on Earth.
Thus, The heat energy released during nuclear fusion. The correct option is D.
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The amount of gas (in terms of moles, mass, and
molecules)
Answer:
was constant
Explanation:
Good luck! :)
Answer:
B. was constant
The first order reaction,so2cl2 to so2+cl2,has a half life of 8.75 hours at 593k.How long will it take for the concentration of so2cl2 to fall to 12.5% of its initial value? 6.24hours 26.2hours 16.2hours 22.6hours
Answer: The time after which the concentration of [tex]SO_2Cl_2[/tex] fall to 12.5% of its initial value is 26.2 hours
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant = 100
a - x = amount left after decay process = 12.5
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{8.75hour}=0.0792hour^{-1}[/tex]
b) for concentration to fall to 12.5 % of initial value
[tex]t=\frac{2.303}{0.0792}\log\frac{100}{12.5}[/tex]
[tex]t=26.2hours[/tex]
The time after which the concentration of [tex]SO_2Cl_2[/tex] fall to 12.5% of its initial value is 26.2 hours
What is the pH of a solution with (H+] = 1 x 103 M?
Which celestial object's period of revolution is the same as its period of
rotation?
Answer:
MOON
Explanation:
ITS PERIOD OF REVOLUTION IS EQUAL TO PERIOD OF ROTATION
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What is the relationship between distance from the Sun and period of
revolution for the planets in our Solar System?
Answer:
T^2 α r^3
Explanation:
The relationship between the period of revolution of planets and their mean distances from the sun is given by Kepler's third law.
Kepler's laws of planetary motion describe the orbits of objects around the sun.
This third law states that; "the square of the period of revolution of planets are proportional to the cubes of their mean distances from the sun. Hence; T^2 α r^3.
Where;
T = period of revolution of the planets
r = mean distance of the planet from the sun