The question is incomplete, the complete question is:
Regina conducted an investigation to determine whether earthworms add nutrients to soil. She used two pots of soil. She added three earthworms to the first pot. She did not add any earthworms to the second pot, which was the control. Regina tested the nutrient levels of the soil in both pots after two weeks.
What type of investigation is Regina conducting?
descriptive
comparative
experimental
procedural
Answer:
experimental
Explanation:
In an experimental study, there is an independent variable, a dependent variable and a set up meant for control.
The control is set up to establish the validity of the study.
Experiments are designed to establish cause and effect relationship. In this case, the experiment was designed to establish weather earthworms add nutrient to the soil.
Answer:
experimental
Explanation:
experimental
Express 749 000 000 in scientific notation,
Answer:
7.49 × 108
Explanation:
Scientific notation is a way to express numbers in a form that makes numbers that are too small or too large more convenient to write. It is commonly used in mathematics, engineering, and science, as it can help simplify arithmetic operations. In scientific notation, numbers are written as a base, b, referred to as the significant, multiplied by 10 raised to an integer exponent, n, which is referred to as the order of magnitude:
Can someone help me with number 4 please?
What is an ionic bond?
Answer:
Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion
Explanation:
pleaseee mark brainliest <3!
what is meant by hydrogen bond
Answer:
The attraction between two atoms that already participate in other chemical bonds is a hydrogen bond
Which of the following statements is correct about the shape of the H2O molecule? Select all that apply.
Water is a linear molecule with bond angles of 180o
Water is a bent molecule with bond angles of 104.5o
Water has two pairs of unbonded electrons which are spread out evenly between the hydrogen atoms
Water’s two pairs of unbonded electrons push the hydrogen atoms further away from their negative charge
Answer:
Water is a bent molecule with bond angles of 104.5o
Water has two pairs of unbonded electrons which are spread out evenly between the hydrogen atoms
Explanation:
Water is a substance with chemical formula, H2O i.e. two hydrogen atoms bonded to one hydrogen atom. The more electronegative oxygen atom draws electron from the less electronegative hydrogen atoms to make the molecule a POLAR ONE. The water molecule assumes a bent shape with bond angle 104.5°.
The oxygen atom has two lone pairs of electrons, which each hydrogen atom is attracted to. This strong attraction forms hydrogen bonds in the water molecule. Hence, the two pairs of unbonded electrons in the water molecule are spread out evenly between the hydrogen atoms.
What is the charge on an electron? -1 0 +1 +2
Answer:
to be honest I don't know
Explanation:
my brain won't work with this
What’s a prefix for -4?
A: cuatra
B:quater
C:-tetra
D:-tretis
Do you guys have viruses wit this website
Please help brainiest is award!
Answer:
C
Explanation:
CH₄ is the formula for methane
which electrons are the valence of electrons of the atom?
Answer:
Valence electrons are the electrons in the outermost shell, or energy level, of an atom. For example, oxygen has six valence electrons, two in the 2s subshell and four in the 2p subshell.
electron configuration of silver
Answer:
[Kr] 4d10 5s1 or 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s1
True or false? The mass number of an atom equals the sum of the protons and
electrons.
Answer:
false, it is the number of protons and neutrons
Explanation:
What is the main difference between a chemical and a physical change? PLEASE HELP ASAP
Answer:
In a chemical change the nature of the substance changes and it is transformed, for example when a piece of wood is burned, the carbon is being transformed into carbon dioxide. A physical change is one where the nature of matter does not vary.
I hpoe help you.
Answer:
physical changes only change the appearance of a substance not it's chemical composition .chemical changes change the substance with a new chemical formula
Explanation:
List the different sizes of sediment.
Answer:
Smallest to Largest:
Clay is smaller then 1/125 mm
Silt is 1/256- 1/16 mm
Sand is 1/16-2 mm
Pebble is 2-64 mm
Cobble is 64-256 mm
Boulder is greater then 256 mm
Explanation:
When we mixed milk and vinegar in the lab demonstration, a/an __.
was created.
Answer:
Plastic
Explanation
Found on google
how many electrons does Neon-21 have?
Answer:
10 electrons
Explanation:
Neon 21 has 10 protons and 11 neutrons. We know that there are the same number of electrons as there are protons. so your answer is 10.
Answer question number 7
Answer:
C
Explanation:
It should be acidic soil that is below pH7. pH2-pH4 is too low and it is a strong acid. Plants won't survive in very high acidity soil
Which of the following is the final stage of a low mass star? *
1 point
For an object that has a volume of 24.5 mL and a mass of 102g, calculate the density of the object
Answer:
The answer is 4.16 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
mass = 102 g
volume = 24.5 mL
We have
[tex]density = \frac{102}{24.5} \\ = 4.163265306...[/tex]
We have the final answer as
4.16 g/mLHope this helps you
Organizing information in a meaningful way is an example of what?
Answer:
Observation
Explanation:
In chemistry a chemist conducts an experiment and he/she concludes some points and arranges information about his/her experiment can be called observation or result
Organizing information in a meaningful way is an example of good management and the proper establishment of the research parameters.
In research, the correct organization of information is of the utmost importance.Information is the key to get proper results during research.That is why researchers must be very careful in the way they handle information.Proper sources should be taken into consideration to do research.The information obtained should be correctly organized and classified, according to the framework of research. This meaningful organization is key to the following interpretation of results.We conclude that organizing information in a meaningful way is an example of the proper control and follow-up process in research to interpret data and have valid conclusions.Learn more about this topic here:
https://brainly.com/question/19171560?referrer=searchResults
Choose the best statement of the octet rule from those listed below atoms lose 8 electrons to become valent atoms lose 8 electrons to become valent, atoms want 8 valence electrons atoms want 8 valence electrons atoms tend to react until they have 8 valence electrons atoms tend to react until they have 8 valence electrons, atoms tend to react in order to have the s2p4 configuration atoms tend to react in order to have the s2p4 configuration, atoms tend to react in order to gain 8 valence electrons atoms tend to react in order to gain 8 valence electrons
Answer:
atoms tend to react in order to gain 8 valence electrons
Explanation:
The octet rule describes the tendency of atoms of elements to react in order to have eight electrons in their valence shell. This is because having eight valence electrons confers stability to the atoms of these elements in the compounds they form.
The octet rule only does not apply to the transition elements or the inner transition elements as only the s and p electrons are involved. the electronic configuration in atoms having an octet is s²p⁶.
For example, sodium atom has one valence electron in its valence shell but a complete octet in the inner shell; it will react with chlorine atom which has seven valence electrons to form a stable compound, sodium chloride by donating its one valence electron in order to have an octet. Similarly, the chlorine atom will then have an octet by accepting the one electron from sodium atom.
to determine the dependent variable, what question should you ask yourself?
How is burning magnesium different from burning methane?
Answer:
oxygen and magnesium come together in a chemical to form a reaction to it compound after it burns then it forms white powder of magnesium oxide but in the process magnesium gives up 2 electrons to oxygen atoms to form powdery product.
when you burn methane it crrates a blue flame in sufficient amounts of oxygen methane burns to give off carbon dioxide (Co2) and water (H2o)
When many earthquakes are studied, there is another common pattern that emerges: a "Shadow Zone". This is an area, for any earthquake, on the Earth where direct S-waves don't arrive at all and P waves are refracted. What do you think causes these P waves to be refracted? *
Answer:
Sudden decrease in the velocity at the boundary.
Explanation:
The shadow zone is the zone of the earth from angular distances of 104° to 140° from a known earthquake that does not directly receive any P waves. Now, this shadow zone occurs as a result of S waves getting stopped completely by the liquid core and the P waves being refracted by the liquid core.
From earlier seismic discoveries, this boundary which is the shadow zone that does not directly receive any P-waves was found to be due to the fact that the P-waves were refracted inwards as a result of the sudden decrease in velocity at the boundary.
Which of the following elements are characterized by having full outermost s and p
orbitals?
F. Period 7
G.
Group 8A
H.
Inner transition elements
J.
Periods 4, 5, and 6
Answer:
Group 8A
Explanation:
Group 8A elements are characterized by having full outermost s and p orbitals. These elements are also known as the noble gases or inert gases. They occupy the last group on the periodic table.
They are known to have an outer shell configuration of ns² np⁶The configuration reveals that atoms of all the elements have completely filled orbitals in their outer shell sublevels. This accounts for the non-reactivity of elements in this group. Most of the elements in the group have high ionization energy and very low electron affinity values.Some of the elements in this group are Neon, Argon, Krypton, Xenon, and Radon.
Answer question number 3
Answer:
A
Explanation:
A mixture is formed when two or more substances are physically mixed together. A compound is formed when two or more substances are chemically combined through a chemical reaction.
the making of ice cubes is an endothermic reaction
Answer:
no
Explanation:
it is not endothermic reaction
What questions might remain that will one day be answered by new technology?
Answer:
Can we find a safe cure for cancer?
Explanation:
pls mark brainliest
1. Write chemical reaction of burning of magnesium
2. Discuss about the reactivity of magnesium
3. Discuss the nature of magnesium oxide whether it is acidic or basic.
4. What will happen?. When magnesium oxide dissolved in water and tested by red litmus.
5. When Mg burns, which type of flame is obtained.
pls answer which u can
Answer:
1.Mg+O2.......MgO2
Explanation:
2.Very reactive towards halogens and reacts with water at room temperature. 3, Magnesium oxide is a simple basic oxide. 4.It will react with water to form magnesium hydroxide which is a base turning red litmus to blue 5.should be white. hope it helped. I help people although when I post a question it is left unanswered and then gets answers after two days when I don't really need it
Each of the four liquids had the same volume, why don’t
they each have the same density?
Key concepts
Physics
Chemistry
Density
Liquids
Introduction
You probably know that when solid objects are placed in liquid, they can sink or float. But did you know that liquids can also sink or float? In fact, it is possible to stack different layers of liquids on top of one another. The key is that all the different layers must have different densities. You can stack them by picking several liquids with a range of densities or by varying the density of one liquid by adding chemicals such as sugar or salt to it. If you choose colored liquids or add food coloring to each layer, you can even create a whole rainbow of colors in one single glass! Want to see for yourself? In this science activity you will stack several liquids—one by one—and create a colorful density column!
Background
Whether an object sinks or floats depends on its density compared with the density of the liquid into which it is dropped. All types of matter—solids as well as liquids—are made up of many different atoms. Depending on the mass of these atoms, their size and the way they are arranged, different substances will have different densities. The density is characteristic for each individual compound and defined as the mass of a compound divided by its volume. In other words, the more matter there is in a certain amount of volume, the denser a substance is. One cubic centimeter of rock, for example, is much heavier than a cubic centimeter of wood. This is because there is much more matter in the same volume of rock compared with the wood.
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Liquids can also have different densities. Freshwater, for example, has a density of about one gram per cubic centimeter at room temperature. Any compound—liquid or solid—that has a higher density than water will sink whereas substances with a lower density than that will float. You can test that for yourself by gathering several liquids that you have in your kitchen such as vegetable oil, corn syrup, dishwashing soap, water, rubbing alcohol and more. Which one of these do you think will sink or float in water? Find out in this activity!
Materials
Glass or cup
Water
Food coloring
Scissors
Rubber band (wide)
Small piece of wax
Popsicle stick
At least two small, clear jars or transparent mini cups (two ounces) with lids
Permanent marker
Masking tape
Three tablespoons
Dark corn syrup
Vegetable oil
Penny
Paper towels
Rubbing alcohol, dishwashing soap and other liquids (optional)
Sugar (optional)
Preparation
Gather all your materials at a workspace that can tolerate spills of all the liquids.
Fill a cup with tap water and add a couple of drops of food coloring to the water.
Ask an adult to help you cut and prepare small pieces (about 0.5 by 0.5 centimeter) of the rubber band, the popsicle stick and the wax.
Place the two empty jars in front of you (without the lids) and label them “1” and “2” with a piece of tape and the permanent marker.
Procedure
Take a clean tablespoon and pour two tablespoons of corn syrup in jar 1.
With the second tablespoon, carefully pour two tablespoons of colored water into jar 1 on top of the corn syrup. What happens to the water on top of the corn syrup? Does it mix or stay separate?
Use the third clean tablespoon to pour two tablespoons of vegetable oil in jar “1” on top of the colored water. Do you see mixing of the liquids? What happens to the oil? Does it float on top or sink to the bottom?
Now take empty jar 2 and add the same liquids—but in reverse order. Start by pouring in two tablespoons of vegetable oil.