Answer: The footprints were made [tex]2.99\times 10^6years[/tex] years long ago.
Explanation:
Radioactive decay follows first order kinetics.
Half-life of isotope X= 500,000 years
[tex]\lambda =\frac{0.693}{t_{\frac{1}{2}}}=\frac{0.693}{500000}=0.00000139year^{-1}[/tex]
The equation for first order kinetics is :
[tex]N=N_o\times e^{-\lambda t}[/tex]
N = amount left after time t = 0.125 mg
[tex]N_0[/tex] = initial amount = 8.00 mg
[tex]\lambda[/tex] = rate constant
t= time
Putting the values we get:
[tex]0.125=8.00\times e^{- 0.00000139years^{-1}\times t}[/tex]
[tex]0.0156=e^{- 0.00000139years^{-1}\times t}[/tex]
[tex]t=2.99\times 10^6years[/tex]
The footprints were made [tex]2.99\times 10^6years[/tex] years long ago.
How much energy is needed to turn 450 g of zinc into liquid metal at its melting point? (Round your answer to the nearest tenth) *
Answer:
Explanation:
Latent heat of fusion of zinc = 7.322 kJ / mol
molecular weight of zinc = 65 g
450 gram = 450 / 65 = 6.92 mole
Heat required to melt 450 g of zinc = 6.92 x 7.322 kJ
= 50.67 kJ .
= 50.7 kJ .
Where are hormones produced in animals, and how are they transported throughout the body?
A. Animal hormones are produced in endocrine glands and travel through the blood.
B. Animal hormones are produced in lymph nodes and travel through the lymphatic system.
C. Animal hormones are produced inside the bones and travel through the nervous system.
D. Animal hormones are produced in sweat glands and travel through the skin.
Answer:
Vertebrate Endocrine Glands and Hormones
Unlike plant hormones, animal hormones are often (though not always) produced in specialized hormone-synthesizing glands (shown below). The hormones are then secreted from the glands into the blood stream, where they are transported throughout the body.
I WILL GIVE YOU BRAINLIEST HELP ME!!!
Answer:
It is the first one
Explanation:
Due to the fact that political discretion would be so only a few or a group of indviduals could control or know certain things
Answer: yeah is the first one
Explanation:
It is a mixture that consists of a liquid solvent and dissolved solute.
Answer:
A solution is a homogeneous mixture consisting of a solute dissolved into a solvent . ... The solute is the substance that is being dissolved, while the solvent is the dissolving medium. Solutions can be formed with many different types and forms of solutes and solvents.
Answer:
A solution is a homogeneous mixture consisting of a solute dissolved into a solvent .
Explanation:
Who was martin Luther king and how is he celebrite
Answer: martin luther king jr
Explanation: He led peaceful protests against the discrimination that the people of the United State did against African American men, women, and children. He was a celebrity due to his have "I a dream speech" that he said in front of the lincoln memorial. Plus he didn't approve of violence when trying to protest African American rights.
Answer:
Who is Martin Luther King and why is he famous?
Exsplanation
A Baptist pastor and civil rights activist, King worked to end legal segregation of blacks in the United States. He gave his famous “I Have a Dream” speech at the August 1963 March on Washington, and won the Nobel Peace Prize in 1964 at age 35 – the youngest man to have received the award.Apr 4, 2018
which of the following units of measurement would you use to describe the length of your pencil?
Answer:
cm
Explanation:
cm is the most appropriate unit - metres is too big and mm is too small
what is action force?
Answer:
is force acting in one direction
Answer:
hope this helps!
as described by the third of Newton's law of motion of classical mechanics, offices occurs in pairs such that is one object exerts a force on another object, then the second object exerts an equal and opposite reaction Force on the first.
I WILL GIVE U BRAINLIEST!!!!!!!
Answer:
I think its b. if not sorry but its the one that makes most sense
Explanation:
Answer:
B
Explanation:
Hope this helps you have a nice day!
What is the underlying, fundamental force for the formation of all chemical bonds?
A detailed explanation would be best, please.
Answer:
[tex]it \: is : \\nuleic\: force\: of\: ( attraction \: and \: repulsion).[/tex]
Explanation:
[tex]this \: is \: because, \: for \: any \: type \: of \: chemical \\\: combination \: (bonding) \: to \: be \: possible, \\ there \: must \: exist\: an \: equilibrium \: between \: \\ the \: force \: of \: attraction \: and \: repulsion.[/tex]
Answer:
bonds are formed by joining atoms whether same or different elements to form molecules by uses of forces of attractions
List harmful effects of global warming? PLZZ HELP WHOEVER IS FIRST ILL MARK BRAINLEIST
Answer:
first theres the poliution one of the biggest things thats starts global warming then theres recycle and non recycle because people mix there trash up when their not suppossed to.
Explanation:
Please help I’ll give brainiest!
Answer:
Im sorry if u get it worng but is it the 3rd one?
Explanation:
a student is using colored beads to make a model of aluminum sulfate, Al2(SO4)3.
Aluminum atoms are represented by green beads, sulfur atoms by blue beads, and
oxygen atoms by yellow beads. What combination of beads should the student use for
the model?
The combination of beads should the student use for the model :2 green, 3 blue and 12 yellow
the modelFurther explanationIn the chemical formula of a compound there are numbers:
1. The number indicates the number of atoms written after the element symbol
2. The number after the parentheses represents the number multiplied by the number of atoms in parentheses.
3. The number before the chemical formula shows the number of molecules behind it, which is usually used in equations
To calculate the beads needed to make a model, we must count the number of atoms of the Al₂(SO₄)₃ molecule
In the Al₂ (SO₄) ₃ molecule there are 3 atoms : Al, S, and O
1. Number of Al atoms: 2 2. The number of atoms S = 3 x 1 = 3 3. The number of atoms O = 4 x 3 = 12So the combination of beads
2 green(for Al), 3 blue(for S) and 12 yellow(for O)
Answer:
2 blue, 3 yellow, and 12 green
Explanation:
Summary about helium
Answer: Helium is an type of air that can be used to inflate balloons, balls, and other things that require air. The carbon dioxide we breath out is similar to this helium.
Hope this helps!
A substance with a pH of 3 has more ____________ions than ____________ions
Answer:
Hydrogen... Hydroxide
Explanation:
The number in pH is a logarithm, so when something has a higher pH by 1, it is 100 times more powerful.
Besides, the H in pH is Hydrogen.
3. magnesium oxide + ?______________________ magnesium nitrate + water
word equation:
________________________________________________________________
full equation:
________________________________________________________________
Ionic equation:
________________________________________________________________
Answer:MgO reacts with nitric acid
1. In part 1, you collected data about how the amount of sugar affects the amount of gas produced. Analyze those data and draw a conclusion. (16 points) a. What gas inflated the balloons? (2 points)
Answer:
carbohydrate is an essential biomolecule so the affect of suger fluctuates when enzyme consumes the substrates of glucose molecules
Now look closely at the patterns in the table. Compare the elements in each column and row. What can we say about
elements in the same group and elements in the same period of the periodic table?
Select all the correct answers.
The number of electrons in the second energy level increases by one down each column.
Elements in the same row have the same number of occupied energy levels.
For each column, the last occupied energy level has the same number of electrons.
The number of electrons in the first energy level increases by one from Li to Ne.
Answer: Elements in the same row have the same number of occupied energy levels. For each column, the last occupied energy level has the same number of electrons.
Explanation: Straight from PLATO.
On comparing the elements we can say that:
B. Elements in the same row have the same number of occupied energy levels.
Elements in periodic table:
In the periodic table, elements are arranged in an order of increasing atomic number. It comprises of seven periods and eighteen groups.
The elements present in the same row or in the same period will have equal number of energy levels or shells.
Thus, option B is correct.
Find more information about periodic table here:
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How many elements are in this chemical formula?
HCl
Group of answer choices
2. What type of bonding would be expected between the following atoms?
a. Li and F
c. I and Br
b. Cu and S
d. S and O
Considering the definition of covalent and ionic bond, the type of bonding that would be expected between the following atoms is:
Li and F: Ionic Bond I and Br: Covalent Bond Cu and S: Ionic Bond S and O: Covalent BondThe covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule. Covalent bonds are established between non-metallic elements. These elements have many electrons in their outermost level (valence electrons) and have a tendency to gain electrons to acquire the stability of the electronic structure of noble gas.
An ionic bond is produced between metallic and non-metallic atoms, where electrons are completely transferred from one atom to another. During this process, one atom loses electrons and another one gains them, forming ions. Usually, the metal gives up its electrons forming a cation to the nonmetal element, which forms an anion.
Taking into account the previous definitions, it is first necessary to know if the elements are metallic or non-metallic:
Lithium Li: Metallic atoms Flour F: Non-metallic atoms Iodine I: Non-metallic atomsBromine Br: Non-metallic atomsCopper Cu: Metallic atoms Sulfur S: Non-metallic atoms Oxygen O: Non-metallic atoms
Now you can determine the type of bond of the following pairs of elements:
Li and F: Metallic atoms - Non-metallic atoms: Ionic Bond I and Br: Non-metallic atoms - Non-metallic atoms: Covalent Bond Cu and S: Metallic atoms - Non-metallic atoms: Ionic Bond S and O: Non-metallic atoms - Non-metallic atoms: Covalent BondLearn more:
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Which statement offers an explanation for why some parts of John Dalton's atomic theory were proven to be false?
Scientists today are more diverse and have more educational training
Mistakes were made in key calculations during experimenting
Extensive repeated testing was not completed to verify the results
Technology available at that time was limited.
Answer:d
Explanation:
Answer:
The answer is D
Explanation:
I took the test!
How has cooperation played a role in life's major evolutionary transitions?
Answer:
The cooperation of a species is shown throughout history. Including in our history. Where it be physical evolution or technological. We have helped each other with building, advice, locations, Reproduction, etc.
A cart has a mass of 35kg and a speed of 1.2m/s. What is its kinetic energy
Answer:
The answer is 25.2 JExplanation:
The kinetic energy of an object can be found by using the formula
[tex]KE = \frac{1}{2} m {v}^{2} \\ [/tex]
where
m is the mass
v is the velocity
From the question we have
[tex]KE = \frac{1}{2} \times 35 \times {1.2}^{2} \\ = 17.5 \times 1.44 [/tex]
We have the final answer as
25.2 JHope this helps you
Answer:
25.2 J
Explanation:
Using the kinetic energy formula:
KE = [tex]\frac{1}{2}[/tex]m v²
Plug in the given values:
KE = [tex]\frac{1}{2}[/tex] (35 kg) · (1.2 m/s)²
KE = [tex]\frac{1}{2}[/tex] (35) · 1.44
KE = 17.5 · 1.44
KE = 25.2 J
There is a kinetic energy of 25.2 Joules.
Which of the models best represents CaCO3?
Answer: B
Explanation:
To solve this we must be knowing each and every concept related to CaCO[tex]_3[/tex]. Therefore, the correct option is option B among all the given options.
What is CaCO[tex]_3[/tex]?Carbonate of calcium One of the best-known compounds is CaCO[tex]_3[/tex]. Calcium carbonate is indeed a non-toxic, odorless substance. CaCO[tex]_3[/tex] is a white mineral found naturally in chalks, limestones, and marbles. It is a common material found in rocks as calcite and aragonite.
CaCO[tex]_3[/tex] is most commonly found in limestone. It is a sedimentary rock composed primarily of calcite and is the primary component of eggshells, snail shells, seashells, and pearls. Calcium carbonate is also used in medicine as a source of calcium or as an antacid. Although excessive calcium carbonate ingestion is dangerous and causes poor digestion.
Therefore, the correct option is option B.
To know more about CaCO[tex]_3[/tex], here:
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put 34,100,000 in scientific notation
Answer:
3.41 x 10^7
Explanation:
What subatomic particle identifies any type of
atom?
Answer:
hope it helps..
Explanation:
Number of protons
More information: The atomic number is used to identify an element, and the atomic number is the number of protons in the nuclei of an element. Every element has its own unique number of protons, and therefore, atomic number.
[Ne] 3s^ 2 3p^ 4 can someone tell me the element
Answer:
Sulpher
Explanation:
For this type of questions; calculate the total number of electrons so that you can identify the element from the periodic table.
Neon has 10 electrons. and from 3s^2 and 3p^4 there are 6 electrons.
So the total number of electrons is 16.
The element is Sulpher from group 6 of the periodic table
Johnny wanted to paint the ceiling of his room to show the stars of the Milky Way galaxy. What color(s) should he use?
Answer:
He should use black a light purple brown, tan, blue, and just a tiny bit of pink!
Hope this helps!!
Explanation:
If Johnny wanted to show the brightness of the stars, he should use blue, light blue, yellow, orange, red, and white.
What is Milky way??The Milky Way is a huge collection of stars, dust and gas .
The Milky Way is seen as a mostly flat, irregularly-shaped feature that stretches from side to side The Milky way is the mixture of the colors as blue , yellow , orange and white so that it express the appearance of brightness of stars , dust and gasHence , Johnny should use blue, light blue, yellow, orange, red, and white.
Learn more about milky way below
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Which tools can be used to measure the volume of a substance? Select the two correct answers.
a. tape measure
b. digital balance
c. measuring cup
d. graduated cylinder
Answer:
graduated cylinder and a scale can be used to measure the volume of a substance. hope this is helpful
Explanation:
Is the solution a heterogeneous mixture?
Answer:
nope homogeneous
Explanation:
hope this helps :)
Answer:
SOLUTIONS are homogeneous mixtures. A solution is a mixture of two or more substances in a single phase.
which substance is a mixture? A. table salt B. gasoline C. aluminium D. carbon dioxide