when would a scientist choose to conduct a controlled experiment​

Answers

Answer 1

Answer:a scientist would choose to conduct a controlled experiment when it has all the necessary precautions and has the equipment to do so

Explanation:thank you

Plz mark for brainlist


Related Questions

LAST ATTEMPT! Covalent compound naming !

Answers

Answer:sad

Explanation:

haaaaan   not

If you have 3 g of each substance, which would take up the smallest volume?

Answers

Answer:

Explanation:

f the mass of an object is 35 grams and it takes up 7 cm3 of space, calculate the density.

34 pages

How many atoms are AI(OH)3 ?​

Answers

Answer:

It has a total of three elements and seven atoms. Another use that aluminum hydroxide has is it treats the symptoms of too much stomach acid. Some examples of what it treats are: upset stomach, heartburn, and acid indigestion.

Explanation:

Atomicity is the no of atoms present in one molecule. Atomicity of Al(OH)3 = 7.

Please choose and answer 3 of the following 4 questions:
1. Rutherford and JJ Thompson both contributed to what we know about the structure of the atom. What experiments did they perform and how did it change what we know about the structure of the
atom? Furthermore, describe the structure of an atom using only words (no diagrams).
2. Electrons exist outside the nucleus on many different energy levels. When electrons lose energy, they emit waves that are found on the electromagnetic spectrum. What equation would you use to
find the wavelength or frequency of a wave, assuming you know the other value? What is the relationship between frequency and wavelength? What is the relationship between frequency and
energy?
3. Even though electrons move around constantly, scientists use electron configurations to give an "address" to a particular electron. What are the 4 shells that scientists use? How many electrons can
fit into each shell? How can you use the knowledge about these shells and the periodic table to determine the electron configuration of an element?
4. Suppose you know there is an element with an atomic number of 26 and a mass of 60. What do you know about this element? How many subatomic particles does it have? How can you tell?

Answers

Answer:

1. Rutherford performs the gold foil experiment while JJ Thompson performs cathode ray experiment. It was Rutherford's experiment that used positively charged alpha particles (He with a +2 charge) that were deflected by the dense inner mass of the nucleus (nucleus). The conclusion that could be drawn from this finding was that atoms were composed of an inner core that comprised the majority of the atom's mass and was positively charged in nature. The work of JJ Thompson using cathode ray tubes demonstrated that all atoms contain small negatively charged subatomic particles, also known as electrons. According to Thomson's conception of the atom, which had negatively-charged electrons buried inside a positively-charged "soup," the atom was made of plum pudding. Protons, electrons, and neutrons are the three fundamental particles that make up an atom. The protons (which are positively charged) and neutrons (which are neutrally charged) are found in the nucleus (center) of an atom (no charge). The electrons are contained inside the electron shells, which are the outermost parts of the atom (negatively charged).

2. Given that the frequency is 1/T, the equation linking wave speed, frequency, and wavelength is v=f t. The relationship between frequency and wavelength is inversely proportional. The wavelength of the wave with the highest frequency is also the shortest. When the frequency is doubled, the wavelength is cut in half. As a result, the wavelength to frequency ratio is the inverse of the frequency to wavelength ratio. When it comes to carrying energy, the frequency and amplitude of the waves are important factors to consider. The higher the frequency, the greater the amount of energy, and the larger the amplitude, the greater the amount of energy.

3. There are four shells that scientists used. First shell contains 2 electrons. Second shell consists of 8 electrons. Third shell has 18 electrons. Lastly, fourth shell has 32 electrons. 2 electrons can fit into each shell. If you want to compute an electron configuration, first split the periodic table into portions that represent the atomic orbitals, which are the locations where electrons are found. The s-block is represented by groups one and two, the d-block by groups three through twelve, the p-block by groups thirteen through eighteen, and the f-block by the two rows at the bottom.

Explanation:

That's the three questions I chose to answer. Hope it helps;)

calculate the molar mass for each of the following compounds 7. PbSO
8. Ca(OH)2
9. Na3PO4
10. (NH4)2CO3
11. C6H12O6
12. Fe3(PO4)2
13. (NH4)2S
14. Zn(C2H3O2)2

Answers

Answer:

Fe3(PO4)2

Explanation:

calculate the molar mass for each of the following compounds 7. PbSO

8. Ca(OH)2

9. Na3PO4

10. (NH4)2CO3

11. C6H12O6

12. Fe3(PO4)2

13. (NH4)2S

14. Zn(C2H3O2)2

If 10.0 kg of water occupies 10.0 liters, what is the volume in quarts?

Answers

10.0 liters, if 10.0 answer 10.6 :)

The specific heat of water is 4.184 J/gºC. How much energy (in
joules) is required to raise the temperature of 18g of H2O from
283K to 293K?

Answers

62.76 Joules
mark brainleist

PLEASE I WILL GIVE BRAINLISET PLS HELPPPP

Answers

Answer:

the answer is A because the rest wouldnt go good with the work

Explanation:

30 points!!!!

2K + 2H2O → 2KOH + H2

This reaction shows which detail about potassium and hydrogen?
Hydrogen is more reactive than potassium.
Potassium and hydrogen form ionic bonds.
Potassium is more reactive than hydrogen.
Potassium and hydrogen form covalent bonds

Answers

Answer:

2K + 2H2O → 2KOH + H2

So Hydrogen is more reactive than pottasium .

According to law of conservation of matter, 2 moles of potassium react with water to produce 1 mole of hydrogen gas.

So, 2 moles of potassium produce 1 mole of hydrogen gas.

Answer:

A

Explanation:

Hydrogen is more reactive than potassium.

Octane has a density of 0.703 g/ml. Calculate the mass of CO2(g) produced by burning one
gallon of octane. There are 3.79 liters to one gallon.

Answers

The mass of CO₂ gas produced during the combustion of one gallon of octane is 8.21 kg.

The given parameters:

Density of the octane, ρ = 0.703 g/mlVolume of octane, v = 3.79 liters

The mass of the octane burnt is calculated as follows;

[tex]m = \rho V\\\\m = 0.703 \ \frac{g}{ml} \times 3.79 \ L \ \frac{1000 \ ml}{L} \\\\m = 2,664.37 \ g[/tex]

The combustion reaction of octane is given as;

[tex]2C_8H_{18} + \ 25O_2 \ --> \ 16CO_2 \ + \ 18H_2O[/tex]

From the reaction above:

228.46 g of octane -------------------> 704 g of  CO₂ gas

2,664.37 of octane --------------------> ? of CO₂ gas

[tex]= \frac{2,664.37 \times 704}{228.46} \\\\= 8,210.3 \ g\\\\= 8.21 \ kg[/tex]

Thus, the mass of CO₂ gas produced during the combustion of one gallon of octane is 8.21 kg.

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How many moles is 7.78 x 1024
formula units of MgCl2?

Answers

How many moles is 7.78 x 1024

formula units of MgCl2?

answer: 7966.72

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, there are 0.49moles of  MgCl[tex]_2[/tex] in  7.78 x 10²⁴atoms of MgCl[tex]_2[/tex] .

What is mole?

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity of amount of substance. It measure the number of elementary entities of a given substance that are present in a given sample. There are so many formula for calculating mole.

we know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number

mole =given number of atoms ÷ 6.022×10²³(Avogadro number)

given number of atoms of MgCl[tex]_2[/tex]= 7.78 x 10²⁴

Substituting the values

mole= 7.78 x 10²⁴÷ 6.022×10²³

mole = 0.49moles of  MgCl[tex]_2[/tex]

So, there are 0.49moles of MgCl[tex]_2[/tex] in  7.78 x 10²⁴atoms of MgCl[tex]_2[/tex] .

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"Aqueous barium chloride reacts with aqueous sodium sulfate
to produce solid barium sulfate and aqueous sodium chloride."
Which chemical equation correctly translates the description
above?

Answers

Answer:

u should go to gathmath

Explanation:

it's alot better

NEED ANSWER! WILL BRAINLIST!
• Why are tailings an environmental concern?

A. They are a form of sewage that is found in agricultural runoff.
B. They are the remains from mining and contain harmful chemicals.
C. They are the waste products left over from fracking for natural gas.
D. They are a type of greenhouse gas that can enter the atmosphere.

Answers

B. They are the remains from mining and contain harmful chemicals.

Consider Zn + 2HCl → ZnCl2 + H2 (g). If 0.30 mol Zn reacts with HCl, how many grams of HCl are needed?

Answers

Answer:

22 grams

Explanation:

Zn + 2HCl → ZnCl2 + H2

The first step to answering this question is to calculate the amount of moles of HCl needed. We do this by multiplying the coefficient of HCl in the equation over the coefficient of Zn.

0.30mol × [tex]\frac{2}{1}[/tex] = 0.60 mol HCl

Now, to figure out how many grams we must multiply the amount of moles of HCl by it's molar mass. This molar mass can be found by adding the molar masses of all the elements in HCl.

0.60mol × 36.46 g/mol = 21.87g

Using proper sig figs, 22 grams of HCl are required for this reaction.

Bill sets up an experiment to determine and predict the velocity of a marble at the end of a track. He uses an electronic balance to weigh the marble. He then places the marble at the top of the track and releases it. Artie uses the time it takes the marble to pass through a photogate at the bottom of the track to calculate the velocity of the marble. ill notes that his prediction is significantly higher than his calculated velocity. Which error explains this difference? A) Bill forgot to account for friction. B) Bill forgot to zero the balance and found a weight for the marble that was too low. C) Bill weighed the marble in a weighing dish and failed to account for the mass of the weighing dish. D) Bill didn't position the photogate correctly and got the time required for the top of the marble to pass through, rather than reach the middle.

Answers

Answer:

A

Explanation:

USATestPrep

3 useful applications of alkaline earth metals

Answers

Answer:

1 used in paint , toothpaste

2 used in fireworks and magnets

3 used to manufacture alloys

Which of these is a balanced chemical equation?

Answers

CH4+2 O2= CO2 +2 H2O

How are oxidation-reduction reactions related to how you use energy?

Answers

Answer:

In oxidation reduction reactions, one species gets reduced by taking on electron(s) and another species gets oxidized by losing electrons. They also flow by a wire

Explanation:

When the radiation isn't quite strong
enough to kill right away a terrible
Condition follows what is it called
and what is happening.

Answers

When radiation isn’t Enough to kill you but it’s too much for your body to handle you would get what is called radiation poisoning. the symptoms are vomiting, nausea, diarrhea, headache, and several others

what substance changes directly solid to gas
3 examples​

Answers

Answer:

Air FreshenersSpecialized PrintersMoth Balls

                       

The process in which solids directly change to gases is known as sublimation. This occurs when solids absorb enough energy to completely overcome the forces of attraction between them. Dry ice is an example of solids that undergo sublimation.

how many moles of carbonate are there in sodium carbonate​

Answers

There are 0.566 moles of carbonate in sodium carbonate.

CALCULATE MOLES:The number of moles of carbonate (CO3) in sodium carbonate (Na2CO3) can be calculated by dividing the mass of carbonate in the compound by the molar mass of the compound.

no. of moles of CO3 = mass of CO3 ÷ molar mass of Na2CO3

Molar mass of Na2CO3 = 23(2) + 12 + 16(3)

= 46 + 12 + 48 = 106g/mol

mass of CO3 = 12 + 48 = 60g

no. of moles of CO3 = 60/106

no. of moles of CO3 = 0.566mol

Therefore, there are 0.566 moles of carbonate in sodium carbonate.

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Element X has an electron configuration of 2-8-2. This element will combine with the oxide ion to form a compound with the formula

Answers

2+8+2 = 12 electrons
Magnesium has 12 electrons
Magnesium and oxide combine to for Magnesium Oxide
Mg^2+ + O^2- = MgO

Why are naphthalene ball used to protect clothes from insects? How does it gradually decrease and ultimately disappear?​

Answers

Naphthalene balls are used to protect clothes from insects because, when they deteriorate, they create a gas that kills some insects. The naphthalene ball gradually decreases because naphthalene goes through sublimation at room temperature.

_________.__________ and___________ are energy science

Answers

Answer:

Chemical, Mechanical, and Nuclear Energy

Explanation:

Why does the Hubble Space Telescope take clearer pictures than other telescopes?

Answers

Answer:

Space-based telescopes like Hubble get a much clearer view of the universe than most of their ground-based counterparts. ... Ground-based telescopes can't do the same, because the Earth's atmosphere absorbs a lot of the infrared and ultraviolet light that passes through it.

how many compounds can I make with sodium, hydrogen, oxygen?

will give brainliest and 100 points to the correct answer

Answers

Answer:

маны

Explanation:

Answer:

2H2 + O2 → 2H2O

Explanation:

Which statement is false?
a. The density of a gas is constant as long as its temperature remains
constant.
b. Gases can be expanded without limit.
c. Gases diffuse into each other and mix almost immediately when put into the
same container.
d. The molecular weight of a gaseous compound is a non-variable quantity.

Answers

The answer is A- false

2. A compound with an empirical formula of C2H3Br2 has a molar mass of 373.69 g/mol. What is
the molecular formula?
(The molar mass of C2H3Br2 = 186.85 g/mol)
E) C4H6Br4
А) C2H3Br2
B) CHBr
C) C6H9Br6 D) C4H6Br2
(0.5 Points)
A

Answers

C4H6Br4
Because 373.69 is the mass we want, but the empirical mass so far is 186.85

If you notice, 186.85 x 2 is 373.69
So now we times every number in
C2H3Br2 by 2
So c4h6Br4

Empirical is the simplest whole number ratio of elements in a compound. Molecular formula is n times the empirical formula, where n is integers 1,2,... The molecular formula is  C[tex]_4[/tex]H[tex]_6[/tex]Br[tex]_4[/tex]. The correct option is option E.

What is empirical formula?

Empirical formula gives the proportion of the element that is present in a compound. It does not give information about the actual number or the arrangements of the atoms.

n=empirical formula mass÷ molecular formula mass

n=1,2,3....

empirical formula mass = 373.69 g/mol

molecular formula mass=  186.85 g/mol

substituting all the given values in the above formula, we get

n=  186.85 g/mol÷  373.69 g/mol

   = 2

Multiply C[tex]_2[/tex]H[tex]_3[/tex]Br[tex]_2[/tex] by 2, which comes out to be C[tex]_4[/tex]H[tex]_6[/tex]Br[tex]_4[/tex].

Therefore, the molecular formula is C[tex]_4[/tex]H[tex]_6[/tex]Br[tex]_4[/tex]. The correct option is option E.

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Which statement best explains the purpose of using a mole in the measurement of matter? It is commonly used as another unit of mass. It allows chemists to deal with a large number of atoms. It is used only for studying the properties of gases. It explains that substances with the same moles have the same mass.

Answers

Answer:

B) It allows chemists to deal with a large number of atoms.

Explanation:

On Edge 2022

The  statement  which best explains the purpose of using a mole in the measurement of matter is that it allows chemists to deal with a large number of atoms.

What is a mole?

Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.

It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.

It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons .Molar mass has units of gram per mole . In case of molecules, where molar mass  in grams present in one mole  of atoms is its atomic mass.

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Which of the following is a completely elastic collision? A. a ball rebounds against a wall, reversing its direction, but at only half the speed. B. Two balls collide, stick to each other, and move together after the collision. C. Two balls collide and move at a right angle to each other after the collision at a reduced speed. D. Two balls collide head on, each reversing its direction and traveling at half the speed. E. A ball with velocity v collides with a ball at rest; after the collision the first ball is at rest and the second ball has velocity v. I will mark brainliest​

Answers

Answer:

Answer E.

For a collision to be completely elastic, there must be NO LOSS in kinetic energy.

We can go through each answer choice:

A. Since the ball rebounds at half the initial speed, there is a loss in kinetic energy. This is NOT an elastic collision.

B. A collision involving sticking is an example of a perfectly INELASTIC collision. This is NOT an elastic collision.

C. A reduced speed indicates that there is a loss of kinetic energy. This is NOT elastic.

D. The balls traveling at half the speed after the collision indicates a loss of kinetic energy, making this collision NOT elastic.

E. This collision indicates an exchange of velocities, characteristic of an elastic collision. We can prove this:

Let:

m = mass of each ball

v = velocity

We have the initial kinetic energy as:

KE = \frac{1}{2}mv^2 + 0 = \frac{1}{2}mv^2KE=21mv2+0=21mv2

And the final as:

KE = 0 + \frac{1}{2}mv^2 = \frac{1}{2}mv^2KE=0+21mv2=21mv2

Answer:

E

Explanation:

hope this helps

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