Explanation:
Using stratified random sampling, researchers must identify characteristics, divide the population into strata, and proportionally choose individuals for the representative sample. ... For example, individuals who are too busy to participate will be under-represented in the representative sample.
In which Group do most of the elements have 8 valence electrons?
A. Transition metals
B. Alkaline earth metals
C. Halogens
D. Noble gases
Which is classified as an inner transition element?
a) calcium
b) copper
c) fermium
d) helium
is this enough money for this question
A certain type of frog reproduces sexually and has 36 pairs of chromosomes in each of its body cells. How many chromosomes are in each of the frog’s sex cells?
Answer:
The answer is 36 on edgenuity.
A Potassium isotope contains 19 protons, 19 electrons and 21 neutrons. What is its mass number? 40
Answer:
17
Explanation:
you add 19+19 the subtract 21. I think
A potassium isotope contains 19 protons, 19 electrons, and 21 neutrons, so the mass number is 40 as the mass number of the atom is the sum of the protons and the neutrons, the mass number is 40.
What is the significance of the mass number in the atom?The mass number is significant as it is the sum of the number of protons and neutrons present in nucleus of an atom, which determines the atomic weight of an element and also determines its chemical properties and its position on the periodic table. Isotopes of an element have the same atomic number but a different mass number, so they have different properties than the original element.
Hence, a potassium isotope contains 19 protons, 19 electrons, and 21 neutrons, so the mass number is 40 as the mass number of the atom is the sum of the protons and the neutrons, the mass number is 40.
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name two liquid fuels obtained from petroleum
Answer:
Diesel and kerosene.
Hope it helps :)
Answer:
Gasoline
Diesel
Kerosene
LPG
Rethanol
Ethanol
Butanol
In chemistry she wants to know why to certain items or people shock me?
Convert 30°C into kelvin
Answer:303.15
Explanation:
what does the chemical formula Ba(HCO3)2 tell us about number of atoms of each element present
Answer: The chemical formula is Ch(HCO3)2 and Cn(HO3)2
Explanation:
There is 1 atom of Ba, 2 atoms of hydrogen, 2 atoms of carbon, and 6 atoms of oxygen.
What are molecules?The smallest particle of a substance has all of the physical and chemical properties of that substance.
The chemical formula Ba(HCO3)2 tells us about the number of atoms of each element present as follows:
1 atom of Ba
2 atoms of hydrogen
2 atoms of carbon
6 atoms of oxygen.
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Claudia performed a flame test in her lab. The result of her flame test is shown here.
Answer:
Where is the results and what is the question or is there a picture
Explanation:
Questions
1 Describe two ways in which sodium chloride is different from sodium
frorent from chlorine
chlorine
The compound composed of these ions exhibits properties entirely different from the properties of the elements sodium and chlorine. Chlorine is poisonous, but sodium chloride is essential to life; sodium atoms react vigorously with water, but sodium chloride simply dissolves in water.
Which characteristic best explains why gases are more compressible than liquids or solids?
A Gas particles tend to attract one other, while liquid and solid particles tend to repel each other.
B. Gas particles tend to be separated by larger distances than liquid or solid particles are.
C Gas particles tend to move more rapidly than liquid or solid particles do.
D. Gas particles tend to clump together as their temperatures increase
Answer:B
Explanation:
Answer:This chapter begins the first where we will look at matter on a microscopic scale. Matter is made of small particles of atoms or molecules. There are three common states of matter, solid, liquid and gas. A gas and a liquid will change shape to fit the shape of their container. A gas will change volume to fit the volume of the container.
Explanation:
In general, solids are denser than liquids, which are denser than gases. . The particles in the solid are touching with very little space between them. The particles in a liquid usually are still touching but there are some spaces between them. The gas particles have big distances between them.
Solid – In a solid, the attractive forces keep the particles together tightly enough so that the particles do not move past each other. Their vibration is related to their kinetic energy. In the solid the particles vibrate in place.
Liquid – In a liquid, particles will flow or glide over one another, but stay toward the bottom of the container. The attractive forces between particles are strong enough to hold a specific volume but not strong enough to keep the molecules sliding over each other.
Gas – In a gas, particles are in continual straight-line motion. The kinetic energy of the molecule is greater than the attractive force between them, thus they are much farther apart and move freely of each other. In most cases, there are essentially no attractive forces between particles. This means that a gas has nothing to hold a specific shape or volume.
(A fourth state of matter, called plasma, exists when a gas becomes ionized. Plasma exists inside stars and in interstellar gases.)
The cell organelles that contains chlorophyll
Answer:
In plants, photosynthesis takes place in chloroplasts, which contain the chlorophyll. Chloroplasts are surrounded by a double membrane and contain a third inner membrane, called the thylakoid membrane, that forms long folds within the organelle.Which of the following most likely explains why the chemical symbol for calcium is Ca?
A. The symbol C was already used for carbon.
B. The symbol was assigned by modern alchemists.
C. Calcium is made of more than one type of atom.
Answer:
it is a latin word, so B
Explanation:
A metal ‘X’ has high melting point, good conductor of electricity, and is most malleable. Then the metal ‘X’ is A) Cu B) Au C) Fe D) Pt
Answer:
A) Cu
(copper)
The modern atomic theory has been updated over the years as new observations of the atom have been made. What do these changes say about the strength of the modern atomic theory
Answer:
The answer is "It updates reinforce the idea, because it has been checked and modified several times, making it longer lasting".
Explanation:
The description of its empirical data throughout the world is a scientific principle. It's also based on facts and is often extensively tested by researchers. Repetitive done by scientists testing helps to enhance its body of knowledge. As just a result of advances in technology, after observation, data collection, and findings evaluation, scientific facts are checked, modified, and verified.
How should the baking of a pizza be categorized? A) as an exothermic process because the dough releases heat B) as an endothermic process because the dough releases heat C) as an exothermic process because the dough absorbs heat D) as an endothermic process because the dough absorbs heat
Answer:
D
Explanation:
as an endothermic process because the dough absorbs heat
The baking of a pizza be categorized as an endothermic process because the dough absorbs heat.
What is an Endothermic reaction?This is the type pf reaction in which heat is absorbed from the surroundings in a reaction.
During baking, the oven which is the surrounding is usually hot which brings about the dough absorbing the heat. This depicts an endothermic process and makes option D the most appropriate choice.
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What is the total number of protons, neutrons, and electrons in a thallium, TI, atom that has a mass number of 204
Help
Answer:
Name, Thallium. Symbol, Tl. Atomic Number, 81. Atomic Mass, 204.3833 atomic mass units. Number of Protons, 81. Number of Neutrons, 123. Number of Electrons, 81 ... It has a metallic luster when it is first exposed to air but it tarnish quickly
Explanation:
Hope this helped :)
C. A paramecium is a single-celled organism that lives in ponds. It travels at a rate of 2,000 micrometers per second. What is the speed of the paramecium in meters per hour?
Answer:
7.2 meters per hour
Explanation:
It is given that,
The speed of a paramecium is 2,000 micrometers per second.
We need to find the speed of the paramecium in meters per hour.
We know that,
[tex]1\ \mu m=10^{-6}\ m[/tex]
and
1 hour = 3600 seconds
[tex]v=2000\ \dfrac{\mu m}{s}\\\\=2000\times \dfrac{10^{-6}\ m}{(\dfrac{1}{3600})\ s}\\\\=7.2\ \text{meters/hour}[/tex]
Hence, the speed of the paramecium is 7.2 meters per hour.
If you burn a piece of wood, it becomes a different substance. What type of
property is this?
A. Electrical property
O
B. Chemical property
C. Physical property
D. Mechanical property
Answer:
B. Chemical property
Explanation:
Answer:
B
Explanation:
a reaction has taken place in which you can't get back what you started with
Anybody know about this chem problem, please anything helps.
Answer:
B
Explanation:
the second option is right
HELP PLZ !!!!! !!!!
Which of these is a sedimentary rock?
A) Granite
B) Obsidian
C )Quartzite
D) Sandstone
Answer:
D
Explanation:
Terry bought a gold necklace at a pawnshop and was wondering if it was “real” gold. She decided to perform a density test. She placed the necklace in a graduated cylinder of water that had 47.00 mL of water and the water rose to 48.35 mL. She then weighed the necklace and found it to have a mass of 22.89 g. What is the density of Terry’s necklace?
Answer:
d = 16.96 g/mL
Explanation:
Given that,
Initial water level in graduated cylinder is 47 mL and final water level is 48.35 mL.
The weight of the neclace is 22.89 g.\
We need to find the volume of the necklace. We know that, density equals mass per unit volume. So,
[tex]d=\dfrac{m}{V_f-V_i}\\\\d=\dfrac{22.89\ g}{(48.35-47)\ mL}\\\\d=16.96\ g/mL[/tex]'
Hence, the density of Terry’s necklace is 16.96 g/mL.
Answer:
A
Explanation:
The new mine means the supply is high and the price is low, so she can afford the necklace
Which of these elements in GroupA on the periodic table has the largest atomic radius?
A.Cesium
B.Rubidium
C.Potassium
D.Sodium
Answer:
A i think is the answer
Is beans in water a suspension colloid or solution
Answer:
The CORRECT answer is Solution
Explanation:
Since a Colloid is a liquid like substance that cannot be removed from other solids the only possible choice would be a Solution. becuase with a solution you can drain the solution and still get the beans.
What is absolute zero? A) The temperature at which the particles of matter are at their lowest energy points. B) The temperature at which the particles of matter are at their highest energy points. C) Other _______________
Answer:
A) The temperature at which the particles of matter are at their lowest energy points.
Explanation:
Absolute temperature refers to the lowest possible temperature. At this state, no heat energy remains in the substance; the energy of the particles are at their lowest energy points.
During dialysis, water and urea pass from the blood into the dialysis fluid. Proteins stay in the blood.
(a) Name the process by which water passes from the blood to the dialysis fluid.
(b) Describe the process you have named in (a).
(c) Explain why water passes out of blood but proteins do not.
Answer:
Healthy kidneys clean your blood and remove extra fluid in the form of urine. They also make substances that keep your body healthy. Dialysis replaces some of these functions when your kidneys no longer work. There are two different types of dialysis - hemodialysis and peritoneal dialysis. The following is about hemodialysis.
What are five ways to identify a chemical reaction
Answer:
A chemical reaction occurs when a substance is rearranged to form a new substance. It is possible to identify if this has taken place from one of the five signs of chemical change. These changes include color change, temperature change, precipitate formation, gas production and light emission.
Explanation:
hope it helps :))
Answer:
A chemical reaction occurs when a substance is rearranged to form a new substance. It is possible to identify if this has taken place from one of the five signs of chemical change. These changes include color change, temperature change, precipitate formation, gas production and light emission.
hope it helps :)
ANALYSIS
1. Why are resources like air and water considered to be at risk, even though
they are considered renewable?
Answer:
The pollution can cause resources to lessen.
Due to pollution, resources like air and water considered to be at risk, even though they are considered renewable.
What is pollution?Pollution is the presence on an environment or substance, harmful substances that are dangerous to the living organisms found in that environment.
Water and air pollution is a serious risk to human, animal and plant life in the environment.
Therefore, due to pollution, resources like air and water considered to be at risk, even though they are considered renewable.
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Neutrons have a
charge?
neutral
negative
positive
Answer:
Neutrons have a neutral charge
Explanation:
A neutron consists of 3 quarks, 1 up and 2 down. The up quark has a charge of + 2/3e, and the down quarks each have a charge of - 1/3e. So, the charges on the 3 quarks tend to cancel out to produce a neutrally charged particle.
A vial is filled with room temperature water, and blue cold water has been placed at the bottom. A warm water bag sits next to the vial. What do you think will happen?
Explanation:
In the context, a vial which is used in store medical samples is filled with water at room temperature. And the vial is kept on a cold water. Also a water bag containing warm water is kept near the vial.
The cold water kept at the bottom of the vial is having lower kinetic energy while warm water will have higher kinetic energy than the others. Since the water in the vial is at room temperature and it is in touch with the cold blue water, the water in the vial will loose or give its temperature to the cold blue water through conduction as well as convection process since temperature always flows from a hot body towards the cold body.
On the other hand, the warm water placed next tot he vial will give its temperature to the atmosphere.