Answer:
A
Explanation:
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Astatine-210 has a half-life of 8.08 days. What fraction of a sample of astatine-210 is left unchanged after 16.16 days?
Answer:
0
Explanation:
Given parameters:
Half-life = 8.08days
Unknown:
What fraction is left unchanged after 16.16days = ?
Solution:
The half - life of a substance is the time taken for the half of a radioactive material to decay to half.
Day 0 Day 8.08 Day 16.16
100% 50% 0% Parent
0% 50% 100% Daughter
After 16.16 days, non of the original sample will remain unchanged.
Please help :(
I just need the bottom true or false part
Answer:
if you mean question 21
true
Explanation:
sorry if wrong
Perform a DNA extraction from green peas at home or school lab, under adult supervision, by following the given procedure carefully.
Procedure for DNA extraction:
To half cup of split peas, add 1/8 teaspoon of salt and one cup of cold water.
Transfer this mixture in a blender and blend it on high speed for 15 seconds.
Filter the blended mixture, using a strainer, into a measuring container. Observe the amount of mixture you obtain after filtration. Add liquid detergent equal to 1/6 volume of the obtained pea mixture.
Mix by swirling. Allow the mixture to rest for about five to ten minutes.
Transfer this mixture to test tubes. Fill the tubes to about 1/3 of their volume.
Add a pinch of meat tenderizer to each of these tubes. Mix gently to avoid damaging the DNA.
Tilt the test tube, and pour alcohol (75% isopropyl alcohol or 95% ethanol) down the sides of the tube. Add alcohol to about 2/3 volume of the tube. You will obtain two layers. The layer at the top contains the DNA.
Now that you are done with the DNA extraction process, answer the following questions:
What purpose does blending the pea mixture serve?
Why do you need to add liquid detergent?
What role does the meat tenderizer play?
Why is alcohol added and why does the DNA get extracted in the alcohol layer?
Answer:
Blending is done to break open, or lyse, the cells.
DNA resides in the nucleus, which is enclosed by the nuclear membrane. The nucleus is further enclosed by the cell membrane. So, to get the DNA, we need to break open both the membranes. Cell membranes are made up of lipids and proteins. The detergent molecules to attach to the cell and nuclear membranes, causing them to break open.
Meat tenderizer contains the enzyme protease that helps cleave proteins. Even after breaking open the nucleus and cell membrane, the DNA is still protected by cell proteins. Meat tenderizer cleaves the proteins, leaving behind only the DNA molecule.
DNA is insoluble in alcohol and hence, when alcohol is added, it precipitates out the DNA.
Explanation:
PLATO Answer
ClO3− Draw the molecule by placing atoms on the grid and connecting them with bonds. Include all lone pairs of electrons. Show the formal charges of all nonhydrogen atoms, or use square brackets to denote the overall charge. View Available Hint(s)
Answer:
See explanation
Explanation:
The overall charge on ClO3− is shown on the image attached to this answer. If we calculate the formal charges on each atom in the structure, we will notice that one oxygen atom has a formal charge of -1 while all other atoms have a formal charge of zero.
This gives the compound an overall charge of -1 as shown in the image attached to this answer. This is the correct Lewis structure for the compound ClO3− .
The molecule has a formal charge of -1 on all oxygen atoms, and +2 on the Cl atom.
When all the electrons of an atom are shared equally, the charge attained by the atom is known as a formal charge.
The formal charge can be calculated as:
Formal charge = valence electron - non-bonding electron - [tex]\rm \dfrac{bonding\;electron}{2}[/tex]
In the molecule, the formal charge of Oxygen = -1.
In the molecule, the formal charge of Chlorine = +2
The oxygen atom has 8 electrons, in which 2 are shared in the bond formation, and 6 electrons are valence electrons.
The chlorine atom has 7 valence electrons in which 6 electron pairs are shared with the oxygen atom, and 1 lone pair has been available with Cl.
The structure of [tex]\rm ClO_3^-[/tex] molecule has been given in the image attached. The image shows the available lone pairs and the bonding in the structure.
Thus, the molecule has a formal charge of -1 on all oxygen atoms, and +2 on the Cl atom.
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Question 18 of 25
Which sentence best describes what happens when a neutral atom becomes
a positive ion?
A. The protons pull harder on the remaining electrons.
B. The remaining electrons are more easily lost.
C. The remaining electrons spread farther out.
D. The protons push the remaining electrons away.
Answer:
d is the answer I think .....
Is meat a mixture or substance?
Answer:
This type of meat is substance. If you were talking about meters then it would be a system of measurement.
Answer:
Mixture
Explanation:
Meat is composed of approximately 72–75 % water, 21 % nitrogenous compounds (19 % proteins and 1.5 % nonprotein nitrogen compounds which include nucleotides, peptides, creatine, and creatinine), 2.5–5 % lipids, 1 % non-nitrogenous compounds (vitamins) and carbohydrates (a very small amount of glycogen).
the atomic number tells us all of the following except ..
Answer:
b
Explanation:
The atomic number tells us all of the following except B. The order in which the elements were discovered.
What does the atomic number let you know?
The atomic number is the number of protons in the nucleus of an atom. The number of protons outline the identity of detail (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).
What pieces of facts do the atomic number inform you?The atomic variety helps human beings discover factors in step with the variety of protons one atom of the element has. It essentially defines the element. while having a neutral rate, it also offers the variety of electrons the detail has (in one atom). while isotopes are a component, it would not completely exchange the atom.
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Maggie has 4 binders with 30 stamps in each binder. She has 3 binders with 36 baseball cards in each binder. If she gives away 45 stamps to a friend, how many stamps and cards does she have left? Maggie has stamps and cards left.
Answer:
The number of stamps and cards Maggie has left if she gives 45 stamps to a friend is 183
Explanation:
If Maggie gives 45 stamps to a friend, you must calculate the number of stamps and cards she has left.
You know Maggie has 4 folders with 30 stamps in each folder. So the number of stamps she owns is calculated as:
4 folders*30 stamps in each folder= 120 stamps
If Maggie gives 45 stamps to a friend, then the number of stamps she has left will be calculated as the difference (the subtraction) between the stamps she owned and the ones she gives away:
120 stamps - 45 stamps= 75 stamps
On the other hand, she has 3 binders with 36 baseball cards in each binder. So the number of cards she owns is calculated as:
3 binders * 36 baseball cards in each binders= 108 baseball cards
The number of stamps and cards you have left is calculated as:
75 stamps + 108 baseball cards= 183
The number of stamps and cards Maggie has left if she gives 45 stamps to a friend is 183
Ice floats due to its?
Answer: it floats because it’s less dense than water
Explanation: since it’s less dense it floats
Given the name of an element and the number of neutrons, find the mass of an Isotope
The given element nitrogen have 7 electrons and 7 protons. Mass number is the sum of number of protons and neutron. The number of neutrons is 7. Thus mass number of the isotope is 14.
What is nitrogen?Nitrogen is 7th element in periodic table. It is an electronegative element and is included in p block. Nitrogen exists as gas but sometime it can be liquified under high pressure.
Isotopes are atoms with same atomic number and different mass number. Nitrogen have two isotopes. N-14 and N-15. Mass number is the sum of number of protons and neutrons.
Even though isotopes are different in mass number their chemical properties will be similar but there exists slight changes in their physical properties.
Here, we have 7 protons and 7 electrons therefore, the mass number 14.Thus the isotope given in the diagram is N-14.
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Aly's science class was looking at bacteria through a microscope. Aly's teacher said some bacteria can be as small as 0.00365 cm long. What is the length of the bacteria written in scientific notation?
Answer:
[tex]0.00365\ cm=3.65\times 10^{-3}\ cm[/tex]
Explanation:
Aly's teacher said some bacteria can be as small as 0.00365 cm long.
In this problem, we need to write the length of the bacteria written in scientific notation. Any number can be written in the form of scientific notation as follows :
[tex]N=a\times 10^b[/tex]
a is a real no and b is an integer
In the given number, there are two zeroes before 3. We need to shift the decimal after 3. It can be done as follows :
[tex]0.00365\ cm=3.65\times 10^{-3}\ cm[/tex]
Hence, this is the required solution.
A student observes that a popcorn kernel has a hard coat. He places the kernel in a moist paper towel and observes it for several days. He notices that the coat splits and a small root emerges. He concludes that
Answer: Water inside the seed coat creating a pushing force, breaking the seed coat.
Explanation:
Seed germination can be defined as the process by which a new plant emerge out from a seed. The radicle is the first emerging part from a seed and it develops into a root and the plumule is the second emerging part and it develops into a shoot. The light, water, adequate temperature, and soil are the factors that are necessary for seed germination.
According to a given situation, the popcorn kernel will receive the moisture necessary for the germination process, the water will imbibe into the seed coat creating pressure inside the seed and which will cause the seed coat to break and the new plant parts or seedling will emerge out of the seed coat.
12. If the particles of a liquid are always moving, why don't they all come apart from each other and become a gas?
Answer:
even though the particles of a liquid are moving, they are attracted to each other so they don't spread far apart to become a gas.
Explanation:
"but some do when they evaporate"
In liquids, the particles are allowed to move freely rather than the solid. The gaseous particles can move more freely than liquids.
Particles in liquids:In liquids, the particles are placed randomly and thus are allowed to move freely but they do not become a gas as liquids are slightly less compressible than gases. Even though the particles of a liquid are moving, they are attracted to each other so they don't just spread far apart to become a gas.
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Can you think of a way you use the geometrical terms reflection and translation in real life?
I have aids ;-;
Answer:
building really complicated legos
Explanation:
The specific heat of a substance which absorbs 7.5 x 10^3 J of
heat when a sample with a mass of 1.0 x 10^5g of the
substance increases in temperature from 10°C to 90° C will
be:
Answer:
9.4 x 10^-4 J/g°C
What mass of water must be used to dissolve 0.500 kg C2H5OH to prepare a 3.00 m solution?
Answer:
500g Ika= 10.85 mol 500g (46.0699) - 10.35 mol - 3.00m - 13.62 kq 5.
Explanation:
Does this help?
A 3.00 M solution of [tex]C_2H_5OH[/tex] would be prepared by dissolving 0.500 kg of [tex]C_2H_5OH[/tex] in 3.62 kg of water.
Stoichiometric calculation0.500 kg [tex]C_2H_5OH[/tex] is equivalent to (mole = mass/molar mass):
500g/46.07 = 10.85 moles of [tex]C_2H_5OH[/tex]
3.00 M solution of [tex]C_2H_5OH[/tex] can be prepared by dissolving 10.85 moles in (molarity = moles/volume):
10.85/3 = 3.62 Liters of water
3.62 liters of water weighs (density = mass/volume);
1 x 3.62 = 3.62 kg
Thus, 3.62 kg of water will be required to prepare the solution.
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Which one of the following statements about orbitals is INCORRECT?
1) orbitals are regions in space where one is likely to find an electron
2) orbitals can hold up to two electrons
3) orbitals can hold two electrons provided they are spinning in the same direction
4) s, p, d and f orbitals are possible
3) orbitals can hold two electrons provided they are spinning in the same direction
We define an orbital in chemistry as a region in space where there is a high probability of finding an electron.
Each orbital holds a maximum of two electrons which spin in opposite direction according to Pauli exclusion principle.
According to this principle no two electrons can have the same set of quantum numbers. As a result, the spin quantum numbers of two electrons in the same orbital must differ hence they spin in opposite directions.
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2. Mrs. Matthews went to Edisto beach with her husband and two children. She forgot the
sunscreen and the UV Index was extremely high at a level 10. Her whole family got very sunburnt.
Which energy transfer caused the sunburn?
(20 Points)
Radiation
Conduction
O Convection
Kinetic Energy
Answer:
A; radiation
Explanation:
also, please dont use brainly to copy and paste every answer to get them right, use it when u need help
A baseball is thrown a distance of 20 meters. What is its speed if it takes 1 second to cover the distance?
Which statement best describes the process of the formation of the solar system?
Formation. Our solar system formed about 4.5 billion years ago from a dense cloud of interstellar gas and dust. The cloud collapsed, possibly due to the shockwave of a nearby exploding star, called a supernova. When this dust cloud collapsed, it formed a solar nebula—a spinning, swirling disk of material
PLSSSSSSSSSSSSSSSSSSSSSSSSSS HELP
Which of the following best describes physical weathering? (4 points)
A series of chemical changes that wears away at rocks
The movement of rocks from one area to another
Any large-scale event such as volcanic eruptions or earthquakes
A process that breaks down large rocks into smaller piec
Answer:
D. A process that breaks down large rocks into smaller pieces.
Explanation:
Physical weathering if referred to the process of rocks breaking apart without changing their chemical composition. If you look at the other answers, none of them match the description of physical weathering.
Answer:
A process that breaks down large rocks into smaller pieces.
Which machine is the least simple? a bike a screw an inclined plane a lever
Answer: A bike
A bike is composed of various simple machines. It has a wheel and axle as one component, and it also has screws to hold the various parts together, along with levers and pulleys that are connected to the pedals. So all of these simple machine concepts work together to help transport the rider from point A to point B.
The other answer choices of screw, inclined plane, and lever, are fairly simple machines that don't have many things going on at once compared to a bike.
The least simple machine is "A Bike"
Hope this helps!
Populations in the deep-sea vent ecosystem can get energy storage molecules without sunlight. Do you agree or disagree with this claim? Explain your answer.
Answer:
Agree
Explanation:
The deep-sea vent ecosystem gets energy storage molecules without sunlight. Life in the vent ecosystem relies on alternate energy through the use of hydrogen sulfide present in the water emanating from the vent.
The producers that form the basis of the food chain are bacteria that use the hydrogen sulfide to create energy-rich molecule in a process known as chemosynthesis.
The equation of the chemosynthesis is as below:
[tex]CO_2 + 4H_2S + O_2 --> CH_20 + 4S + 3H_2O[/tex]
how does voltage work in a circuit?
Answer:
Voltage is the pressure from an electrical circuit's power source that pushes charged electrons (current) through a conducting loop, enabling them to do work such as illuminating a light.
Explanation:
I hope this is right i found it off a website called fluke!
1. At what temperature dose water freeze
2. at what temperature dose ice melt
3. At what temperature dose water boil
Answer:
1. water will freeze at a temperature below 32 degrees fahrenheit 0 degree celsius.
2. Ice will melt at a temperature above 32 degrees fahrenheit 0 degrees celsius.
3. water boils at 212 degrees fahrenheit or 100 degrees celsius.
how many atoms are in hydrogen
Answer:6.02
Explanation:
Answer:
there are about 6 atoms in hydrogen
The number of atoms of an element in a chemical formula is given by the _________.
Answer:
Explanation: In a chemical formula, the symbols for each element in the compound are followed by subscripts that tell us how many of that element are in the compound. The subscripts that follow each element's symbol indicate how many of that element are in the compound. Notice how H is located in more than one place.
Explanation:
The independent variable and dependent and constant
Answer:
Explanation:
independent-longer wire
dependent-bulbs being brighter
constants-lamp brand and so on
Level 1: You are attempting to identify an unknown substance. Use the table to
answer the questions below.
Substance
Formula
Mass,
Color
Physical
State
Density Boiling
. (g/cm) Point,
Methane
CH
16.0
Gas
Colorless
0.423
-161.5
Ammonia
NH,
17.0
Gas
Colorless
0.70
-33
Unknown
???
???
???
???
???
???
Propane
CH
Gas
Colorless
0.493
-42.1
Bromine
Br.
159.8
Liquid
Red
4.04
58.8
Lithium
Li
6.94
Solid
0.534
1342
Silvery,
white
metal
Magnesium Mg
24.3
Solid
1.74
1090
Silver,
white
metal
The digestive system is a group of organs working together to...