Having a control group is important when doing an investigation why?

Answers

Answer 1

Answer:to help understand the stuff more

Explanation:

Answer 2
Mark Brainliest please

Answer :

Dependent variable depends on the independent variable. ... In a control group in an experimental investigation the independent variable is omitted. Thus the goal is to test if the dependent variable shows any change in the absence of the independent variable.

Related Questions

hii pls help me to balance the equation thanksss​

Answers

Explanation:

2KCLO3 (s) = 2KCl (s) + 3O2 (g)

What is said to have happened to the electrons in an atom in its ground state absorbs a quantum of energy from light

Answers

Answer:

The electron from the ground state to occupy a next energy level. In this case,we say that the electron is excited

Molar mass calculation for Cl^2

Answers

Answer:

Mass of Cl = 35.5

Mass of Cl2 => 35.5×2

=> 71 g/mol

hope that helps ✌

Answer:

71

explain:

The atomic mass of chlorine is equal to the molar mass of chlorine so the molar mass of chlorine is 35.5

=> molar mass for Cl^2: 35,5*2=71

describe the different system of measurement​

Answers

Answer:

A system of measurement is a collection of units of measurement and rules relating them to each other. ... Systems of measurement in use include the International System of Units (SI), the modern form of the metric system, the British imperial system, and the United States customary system.

Explanation:

Hope it works!!!!

Answer:

Systems of measurement in use include the International System of Units (SI), the modern form of the metric system, the British imperial system, and the United States customary system.

4. what reaction fuels the burning of the sun? A.fission B.fusion C.combustion D.transmutation​

Answers

Answer:

A

Explanation:

Answer:

fusion is what fuels the burning of the sun,it's the combining of light elements into heavier elements to produce energy.the sun produces a large amount of energy by combining very light elements with heavier elements.

I hope this helps

What is the meaning of salt

Answers

Answer:

a white crystalline substance that gives seawater it characteristics of taste

Question 10 of 10 A certain seed is surrounded by a sticky coating. It is fairly dense and does not float in water. How is this seed most likely spread?
A. It is dispersed by the wind, and it sprouts after it falls to the ground
B. It drops to the bottom of a body of water, where it sprouts.
C. It attaches to the fur of an animal, and it sprouts after it falls from the animal's fur.
D. Animals eat it, and it is deposited in their waste. ​

Answers

The answer is C

It attaches to the fur of an animal, and it sprouts after it falls from the animal’s fur.

WHICH STATEMENT BEST REPRESENTS A HYPOTHESIS

Answers

Answer:

D

Explanation:

Hypotheses are educated guesses, and the best answer is the one with an if, as it indicates that it's a guess.

Answer:

letter b should be the answer

True or false, The universal gas constant, R, is . 0821 when we use mm Hg as our unit for pressure

Answers

Answer:

This is true.

Explanation:

R should be 0.0821

Good luck!

What does a pH of 7 say about a solution?
O A. The solution is at equilibrium.
B. The solution is neutral.
O C. The solution is acidic.
O D. The solution is basic.

Answers

Answer:

Its's B

The Solution is neutral

Explanation:

what is the anode material used in the extraction of aluminium by electrolysis and why it needs to be changed at interval​

Answers

Answer:

the anode material is graphite(replaceable graphite rods).

The oxygen gas burns away the anode as Carbon dioxide therefore the anode must be replaced continuously.

PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ HELP ME...... ​

Answers

Answer:

a) clockwise

b) clockwise and

c) anticlockwise

In the compound Ni2O3, nickel's oxidation number is_____
oxidation number is -2.
and oxygen's

Answers

Answer:

+3

Explanation:

The name of this compound would be nickel (III) oxide. Oxygen typically has a charge of -2. Given there are 3 oxygen atoms, that would equal a charge of -6. The nickel is the cation and must equal the charge of the anion, so must have a charge of +6. Since there are 2 nickel atoms, the charge on each must be +3.

Which reaction occurs at the cathode in an electrochemical cell?
A. Cu(s) → Cu2+(aq) + 2e
B. Cu2+(aq) + H2(g) → Cu(s) + 2H+(aq)
C. Cu(s) + 2H+(aq) → Cu2+(aq) + H2(g)
D. Cu2+(aq) + 2e → Cu(s)

Answers

Answer:

I could be wrong but I say it's letter b

Explanation:

I hope you have an great night

2. 10.00 grams of a sample of hydrated PtCl4 are heated and lose 3.00 g of water. How many moles of water are combined with each mole of PtCl4?

Answers

Answer:

8 mol

Explanation:

Step 1: Calculate the mass of PtCl₄ in the sample

10.00 grams of a sample of hydrated PtCl₄ are heated and lose 3.00 g of water. The mass of PtCl₄ is:

mPtCl₄ = 10.00 g - 3.00 g = 7.00 g

Step 2: Calculate the moles corresponding to 7.00 g of PtCl₄ and 3.00 g of H₂O

The molar mass of PtCl₄ is 336.9 g/mol.

7.00 g × 1 mol/336.9 g = 0.0208 mol

The molar mass of H₂O is 18.02 g/mol.

3.00 g × 1 mol/18.02 g = 0.166 mol

The molar ratio of H₂O to PtCl₄ is:

0.166 mol H₂O/0.0208 mol PtCl₄ ≈ 8 mol H₂O/ 1 mol PtCl₄

relate the pH of a solution to its hydronium and hydroxyl ion concentration and its acidity or basicity
brain list if your answer is good

Answers

when ph decrease that means acidity increase

when ph increase that means basicity increase

the element of group 1 are reactive but those of group 18 are inert, why​

Answers

Answer:

Because elements of group  1 does not have stable electronic configuration and elements of group 18 have stable electronic configuration.

Explanation:

Because elements of group 1 do not contain stable electronic configuration and elements of group 18 include stable electronic configuration.

What are the element of group 1?

Group 1 elements contain the alkali metals, Li, Na, K, Rb, Cs, and Fr. The alkali metals exist all soft, shiny, and metallic when cut. They react efficiently with water, have low melting points and densities, and are good conductors of electricity. They all include one valence electron that they lose easily to form ions. Noble gas exists as any of the seven chemical elements that create up Group 18 (VIIIa) of the periodic table. The elements exist as helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).

The element of group 1 exist as reactive but those of group 18 exist as inert Because elements of group 1 do not contain stable electronic configuration and elements of group 18 include stable electronic configuration.

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What species is reduced in the reaction Fe + AgNO3 → Fe(NO3)3 + Ag?
A. Agt
B. Fe
C. NO3
D. Fe3-

Answers

The species that is reduced in the reaction is Fe. Option B

The process by which an atom gains an electron, thereby lowering or decreasing its oxidation number. Basically, the positive character of the species is reduced. Reduction occurs when an atom gains one or more electrons during a chemical reaction. This means that the oxidation number decreases. This is when an atom gains an electron because electrons have a negative charge.

Acquires a negative charge that reduces the oxidation number. Reduction involves a half-reaction in which a chemical species reduces its oxidation number, usually by gaining an electron. The other half of the reaction involves oxidation in which electrons are lost. Reduction and oxidation together form a redox reaction. As the oxidation number increases, the atom is oxidized, and as the oxidation number decreases, the atom is reduced.

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Answer: Ag+

Explanation: I just took the test.

A student was given a 2.850-g sample of a mixture of potassium nitrate and potassium bromide and was asked to find the percentage of each compound in the mixture. She dissolved the sample and added a solution that contained an excess of silver nitrate, AgNO3. The silver ion precipitated all of the bromide ion in the mixture as AgBr. It was filtered, dried, and weighed. Its mass was 1.740 g. What was the percentage of each compound in the mixture

Answers

Answer:

See explanation

Explanation:

The reaction occurs as follows;

KBr(aq) + AgNO3(aq) ----> AgBr(s) + KNO3(aq)

Number of moles of AgBr formed = mass /molar mass =1.740 g/187.77 g/mol = 0.0093 moles

From the reaction equation;

1 mole of KBr yields 1 mole of AgBr

Hence the number of moles of KBr reacted = 0.0093 moles

Mass of KBr present = 0.0093 moles × 119g/mol = 1.11 g

Mass of KNO3 = 2.850 g - 1.11 g = 1.74 g

Percentage of KBr = 1.11 g/2.850 g × 100 = 38.9%

Percentage of KNO3 = 1.74 g/2.850 g × 100 = 61.1%

Determine the mass of oxygen in a 45.0 g sample of calcium carbonate

Answers

Answer:

The mass of oxygen in 45.0 g sample of calcium carbonate is approximately 21.58 g

Explanation:

The chemical formula for calcium carbonate is CaCO₃

The molar mass of CaCO₃ = 100.0869 g/mol

The mass of oxygen in one mole of CaCO₃ = 3 × 15.999 g = 47.997 g

The mass of oxygen in 45.0 g sample of CaCO₃, m, is goven as follows;

m = 45.0/100.0869 × 47.997 g ≈ 21.58 g

The mass of oxygen in 45.0 g sample of calcium carbonate, m ≈ 21.58 g

Water glass is found in

A. Liquid form at room temperature

B. solid state at room temperature

c. semi liquid form at room temperature

D. None of above​

Answers

Answer:

liquid form

Explanation:

am i right? if right like

Answer:

semi-liquid at room temperature

please hurry which statement is a scientist most likely to use in describing work

Answers

b i think ye ghhhjhhjjjkxhb

Formation of HCl from H₂and Cl₂ is example of

photochemical

electrochemical

displacement​

Answers

Answer:

Combination reaction.

Explanation:

The reaction depicted in the question is;

H2 (g) + Cl2 (g) ⟶ 2HCl (l)

Now, this reaction shows that two reactants namely hydrogen and chlorine react to form a single product named Hydrogen chloride. This process is called combination reaction.

2. A photon of wavelength for 4 x10 -7 m strikes on the metal surface the work
function of the metal being 2.13 eV.Calculate (i)the energy of the photon in
eV(ii) the kinetic energy of the emission(iii) velocity of the photoelectron
[1ev=1.602x10-19 J]

Answers

Answer:

See explanation

Explanation:

Energy of the photon;

E = hc/λ

h= Planks constant

c= speed of light

λ = wavelength

E= 6.6 × 10^-34 × 3 × 10^8/4 x10 -7

E = 4.95 × 10^-19 J

If 1ev=1.602x10-19 J

x = 4.95 × 10^-19 J

x= 3.1 ev

From Einstein's photoelectric equation;

KE = E - Wo

Where;

KE = kinetic energy of ejected photoelectron

E= energy of the photon

Wo= work function of the metal

KE = 3.1 eV - 2.13 eV

KE= 0.97 eV

KE = 0.97 eV × 1.602x10-19 J

KE = 1.55 × 10^-19 J

KE = 1/2 mv^2

1.55 × 10^-19= 1/2 × 9.1 × 10^-31 × v^2

v= √2 × 1.55 × 10^-19/9.1 × 10^-31

v= 5.8 × 10^5 m/s

Name one diatomic compound which is mononuclei​

Answers

Answer:

Common diatomic molecules include hydrogen (H2), nitrogen (N2), oxygen (O2), and carbon monoxide (CO). Seven elements exist as homonuclear diatomic molecules at room temperature: H2, N2, O2, F2, Cl2, Br2, and I2. The bond in a homonuclear diatomic molecule is non-polar due to the electronegativity difference of zero.

Why does increasing the temperature make a solid dissolve faster?

- The solvent molecules bump into the solid more often.
- The solid is melted before mixing into the liquid.
- The chemical bonds of the solid are broken faster.
- The pressure of the solute on the solid is increased.

Answers

Answer:

The solvent molecules bump into the solid more often

Explanation:

Increasing the temperature makes a solid dissolve faster because the solvent molecules bump into the solid more often.

What happens when you increase the temperature of the solvent?

If we heat the solvent, the average kinetic energies of its molecules increase. Hence, the solvent is able to dislodge more particles from the surface of the solute. Thus, increasing the temperature increases the solubilities of substances. For example, sugar and salt are more soluble in water at higher temperatures.

Does raising the temperature make a substance dissolve faster in a solvent?

The temperature of the solvent is another factor that affects how fast a solute dissolves. Generally, a solute dissolves faster in a warmer solvent than it does in a cooler solvent because particles have more energy of movement.

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Please help with the Volume one

Answers

Answer:

im a just achild

Explanation:

Answer:

c

Explanation:

0.5dm³

follow me if you want

A sample of lithium sulfate, (Li2SO4), has 2.94 x 1023 atoms
of lithium. How many moles of lithium sulfate is the sample?

Answers

Answer:

0.245 moles

Explanation:

moles of lithium = 2*moles of Li2SO4

so moles of LI2SO4=2.94*10^23/(2*6*10^23)=0.245

One mole of lithium sulphate contains 1.2 .022 × 10²⁴ atoms. Thus, the number of moles of this compound which contains 2.94 × 10²³ Li atoms is 4.08 moles.

What is one mole?

Any substance containing 6 .022 × 10²³ number of atoms is called one mole of that substance. This number is called Avogadro number. Hence, one mole of every elements or molecules contains Avogadro number of atoms.

Similarly, one mole of any compound contains 6 .022 × 10²³ molecules. The weight of one mole of a compound is called its molar mass. The mass of one mole of an element is called its atomic mass.

Hence, one mole of lithium sulphate contains 2 × 6 .022 × 10²³  atoms of lithium. Therefore, the number of moles of lithium sulphate containing 2.94 × 10²³ Li is :

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What is the energy of a photon that emits a light of
frequency 6.42 x 1014 Hz?
A. 4.67 x 10-19 J
B. 4.25 x 10-19
C. 3.10 x 10-19 J
D. 9.69 x 10-19 J

Answers

Answer:

Option B is correct [4.25 x 10-19J]

Explanation:

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4.78×[tex]10^{-19}[/tex] J  is the energy of a photon that emits light of

frequency 6.42 x[tex]10^{14}[/tex] Hz.

What is the frequency?

Frequency is the rate at which current changes direction per second. The energy of a single photon is given by:

E =hν

where

E is the energy

h is the Planck constant

f is the frequency of the light

The chemical equation for the energy of a photon is given by:

E =hν , where h is the Planck constant and ν is the frequency.

E =hν = 6.626×[tex]10^{-34}[/tex] Js × 7.21×[tex]10^ {14}[/tex]

[tex]s^{-1}[/tex] = 4.78 ×[tex]10^{-19}[/tex] J

Hence, 4.78×[tex]10^{-19}[/tex] J  is the energy of a photon that emits light of

frequency 6.42 x[tex]10^{14}[/tex] Hz.

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Uranium-235 and uranium-238 are different ________ of uranium
(Apx answers please)

Answers

Answer:

Isotopes

Explanation:

An isotope are the atoms of an element with similar chemical identity and number of protons but different atomic masses. This means that isotopes of an element differ from one another by their number of NEUTRONS.

For example, the uranium element possesses isotopes as follows: Uranium-235 and uranium-238. This two isotopes have the same chemical identity and number of protons/atomic no., which is 92. However, the atomic masses (235 and 238) are different.

Answer:

Isotopes

Explanation:

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