9. Tomato plants in a garden are not growing
well. The gardener hypothesizes that the soil
is too acidic. To test this hypothesis
accurately, the gardener could
(1) plant seeds of a different kind of plant
(2) move the tomato plants to an area with
less sunlight
(3) change the pH of the soil
(4) reduce the amount of water
available to the plant

Halogen-fluorine,chlorine,bromine,iodine

Group II A- Beryllium,magnesium,calcium,strontium ,barium ,radium

Non-reactive- Helium,neon,argon,krypton,xenon,radon

Alkali metal-lithium ,sodium,potassium,rubidium,caesium,francium.

It is a representation of chemical elements in a tabular format.It is a graphical representation of modern periodic law which states that the properties of elements are a periodic function of their atomic numbers.

The periodic table is divided into 4 blocks, rows of the table are called periods and columns are known as groups. Elements belonging to the same group show same properties.

First periodic table  developed and accepted was by Russian chemist Dmitri Mendeleev in 1869.He formulated the periodic law as properties of the elements are a periodic function of their atomic masses.

Till date 118 elements have been discovered and all have been successfully placed in the periodic table based on their properties.

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Answer:

Use the periodic table to choose the element that matches each description.halogen: 

✔ iodine✔ magnesium

✔ argon ✔ potassium

Answer: 40 days

Explanation: The substance completely disintegrates in 20 days the substance completely disintegrates in 40 days 1/8 part of the mass of the substance will be left intact at the end of 40 days.

Answer:

Mass = 9.58 g  

Explanation:

Given data:

Mass of Fe₂O₃ formed = ?

Mass of Fe = 6.7 g

Solution:

Chemical equation:

4Fe + 3O₂        →    2Fe₂O₃

Number of moles of Fe:

Number of moles = mass/molar mass

Number of moles = 6.7 g/ 55.8 g/mol

Number of moles = 0.12 mol

now we will compare the moles of Fe and Fe₂O₃.

                         Fe         :          Fe₂O₃

                           4         :              2

                         0.12       :          2/4×0.12 = 0.06 mol

Mass of Fe₂O₃:

Mass = number of moles × molar mass

Mass = 0.06 mol  × 159.69 g/mol

Mass = 9.58 g  

Density is defined as the mass divided by volume.

Density is also known by the name of viscosity.

Density is denoted by D.

It's unit is basically denoted by kg/m^3.

The density of the block is 0.42 g/cm^3.

The formula of the density is, Density = mass (m) / volume (v)

Now, it is given in the word problem that,

Mass of pine wood = 27g

Volume = 4^3 = 64 cm^3

Thus, Density = 27 g /64 cm^3 = 0.42 g/cm^3.

Hence, the density of the block of pine would be 0.42 g/cm^3

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Answer:

A

Explanation:

Answer: is Cesium (Cs)

Answer:

Low mass star phases

Explanation:

Helium fuses into carbon, the core of the star collapses. Once this happens, the outer layers become exhausted from the weight and this leads a planetary nebula to be formed from the outer layers. The core of the star remains a white dwarf for some time, but eventually it cools down and evolves to a black dwarf.

Empirical formula tells us the relative ratios of different atoms in a compound.

The chemical formula for a compound obtained by composition analysis is always the empirical formula.

How to calculate Empirical formula:

Linalyl acetate (bergamot oil):

              Carbon               Hydrogen                  Oxygen

                73.41 %                   10.29 %                  16.30 %

             73.41 / 12               10.29 / 1                   16.30 / 16

               6.11                          10.29                        1.01

            6.11 / 1.01                10.29 / 1.01                1.01 / 1.01

                 6                            10                                1

          Empirical formula : C₆H₁₀O

Thus we can conclude that empirical formula of linalyl acetate is  C₆H₁₀O

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The empirical formula for Linalyl acetate expresses the relative proportions of different atoms in a compound.

Linalyl acetate is a phytochemical found in a variety of flowers and spice plants. It is an important component of bergamot and lavender essential oils. It is the linalool acetate ester, and the two are frequently found together.

Hence, the empirical formula describes the relative proportions of different atoms in a compound. The chemical formula for a compound obtained through composition analysis is always the empirical formula.

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Answer:

λ  =0.93×10⁻⁶ m

Explanation:

Given data:

Wavelength of wave = ?

Frequency = 3.23 ×10¹⁴ s⁻¹

Solution:

Formula:

Speed of wave = frequency × wavelength

speed of wave = 3×10⁸ m/s

by putting values,

3×10⁸ m/s = 3.23 ×10¹⁴ s⁻¹ × λ

λ  = 3×10⁸ m/s  /  3.23 ×10¹⁴ s⁻¹

λ  =0.93×10⁻⁶ m

"A solution of 5 M HCl is already made. You need to dilute the solution to 1 M HCl. The 1 M HCl solution is less concentrated." Thus, option b is correct.

Molar concentration has been the molarity of the solution that measures the amount of the solute present in the liter solution. It describes the solute concentration that depends on the volume.

The dilution of the solution by increasing the volume results in a decrease in the concentration as molarity and volume show an inverse relationship. So, 1 M is less concentrated than 5 M solution.

Therefore, option b. less concentrated is the correct blank.

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Your question is incomplete, but most probably your full question was, A solution of 5 M HCl is already made. You need to dilute the solution to 1 M HCl. The 1 M HCl solution is ____________.

a. more concentrated

b. less concentrated

c. neither

d. both less and more concentrated

Answer:

The phenotypic percentage of having yellow or green seeds is 50% for having either of the two colours

Explanation:

The crossing to determine the offsprings is shown in the image attached where we have two green (Yy) seeds and two yellow (yy) seeds as offsprings.

Thus, the phenotypic percentage of having yellow or green seeds is 50% for having either of the two colours.

Note, the dominant allele is "Y" while the recessive allele is "y". Thus, Yy would produce a yellow colour while yy would produce a green colour (as both mentioned in the question).

Also note that phenotype describes the outward properties/characteristics of an individual.

Mass of HCl produced :15.59 g

Reaction

2NaCl + H₂SO₄ → 2HCl + Na₂SO₄

Excess = H₂SO₄

Limiting = NaCl

mass NaCl = 25 g

mol NaCl(MW=58.5 g/mol) :

[tex]\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{25}{58.5}=0.427[/tex]

From the equation, mol ratio NaCl : HCl = 2 : 2, so mol HCl = mol NaCl =0.427

Mass of HCl(MW=36.5 g/mol) :

[tex]\tt mass=mol\times MW\\\\mass=0.427\times 36.5\\\\mass=15.59~g[/tex]

Answer:

its the fourth one please mark as brainlest

Explanation:

A chemical reaction is the combination of two or more elements or compounds to form one or more products. The combining compounds or elements are called reactants. Hence, sodium and chlorine are reactants. Thus option D is correct.

A chemical reaction is a change in the chemical composition that occurs when two or more species unite to create a new product by forming or breaking chemical bonds.

The reactants are the organisms that are reacting. In a reaction's chemical equation, they are shown on the left side. The right side of the arrow is where the products are shown.

Consider the reaction of sodium and chlorine to give NaCl.

Na + Cl ⇒ NaCl.

NaCl is the product in this reaction. Na and Cl are the reactants. Hence, option D is correct.

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Answer:

I think its A

Explanation:

Answer:

Mass = 17.8 g

Explanation:

Given data:

Number of atoms of Ca = 2.68 × 10²³

Mass in gram = ?

Solution:

Avogadro number:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

2.68 × 10²³ atoms × 1 mole  /6.022 × 10²³ atoms

0.445 mol

Mass in gram;

Mass = number of moles ×  molar mass

Mass = 0.445 mol  ×  40 g/mol

Mass = 17.8 g

The statement that all bonds in alkanes, alkenes, and alkynes can freely rotate at room temperature is false.

Alkanes are saturated hydrocarbons with single covalent bonds. All bond in alkanes can freely rotate.

For example, propane is a three carbon alkane (acyclic saturated hydrocarbon).

Chemical formula for the molecule of propane is CH₃-CH₂-CH₃.

Alkenes and alkynes are unsaturated hydrocarbons. Alkenes have one double bond between carbon atoms, while alkynes have one triple bond between carbon atoms. There is no free rotation in double and triple bonds.

R₂C=CR₂ is general formula for the alkenes.

R–C≡C–R is general formula for the alkynes.

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Answer:

Be Electron configuration: 1s2 2s2

Be Orbital Diagram: \//\    \//\ (it would be little arrows going up and down to show the spins)

F Electron Configuration: 1s2 2s2 2p5

F Orbital Diagram: \//\    \//\    \//\ \//\ \/

Answer:

I think the answer Is 0.636 mol of CO2!

The empirical formula of oxide of iron is Fe2O2 and its name is iron oxide.

Given:

Solution:

Now, calculate the relative mass of iron in iron oxide = Percentage of iron by mass / At. mass of iron

Relative mass of iron = 77.75/55.85 = 1.39

Relative mass of oxygen = Percentage of oxygen by mass / At. mass of iron = 22.25/16 = 1.39

Now the calculate the molar ratio of iron to oxygen = 1.39 : 1.39 = 2:2

Thus, the empirical formula of iron oxide is Fe2O2 and its name is iron oxide.

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Answer:

option d

Explanation:

please mark me brainliest

Answer: S₅Br₆

Explanation: The prefix “penta-“ means five, and the prefix “hexa-“ means six.

N-methyl-2-pyrrolidone is a very reactive compound. It reacts in an acidic medium to form a variety of products. Some reactions involve the ring-opening step.

The structure of N-methyl-2-pyrrolidone is given below:

The compound has a five-membered ring, which consists of four carbon atoms and one nitrogen atom. The ring has one oxygen attached to it via the double bond, and one methyl group is attached to the nitrogen atom.

The chemical reaction involved is as follows:

The structure of the product is given below:

N-methyl-2-pyrrolidone on reaction with strong aqueous acidic medium followed by the treatment of heat results in the opening of the ring and forms a compound having a carboxylic group at one end and protonated nitrogen atom which has one methyl group attached to it, at another end

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Answer:

D. 10mm = 1 cm

E. 1000m = 1mm

G. 100 cm = 1 m

H. 1 m = 10 dm

Answer:

using a diffrent colored light with a higher frequency

Explanation:

Answer:

b

Explanation:

i took the test edg2021

Answer:

b.

it is a warm air mass over a continent

Explanation:

The environment is indispensable in the molding of humans from pre historic times.

The term environment has to do with the surroundings of man. It is the area that surrounds man. Man is shaped by his environment because it has a profound influence on how man reasons and behaves.

In Psychology, the nature - nurture controversy has been a big subject of debate. This theory holds that the environment in which a person was born has a profound influence on the attitudes and perceptions of the individual.

This has held true in so many instances for instance, the faiths that we profess for most of our lives is the result of the religious upbringing that we received in the earlier years of life.

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Answer: 120 mph or 2 mpm

Explanation: 60/5= 12

12*10=120mph

Going 10 miles in 5 minutes means you would be able to go 20 miles in 10 minutes. You would have a total of 12 five minute blocks at 10 miles each. 60 miles in 30 minutes or 120 in 60 minutes.

Or 10 miles in 5 minutes would be 2 miles in 1 minute. (10/5=2)

Answer:

300 m

Explanation:

Answer:

300

Explanation:

20x15=300

i know that someone else already got this i just showed the work