hi, if your looking for extra points (50+) and br ainiest here is ur chance, answer this question correctly plz

Answer:

B) A control group is used for comparison to other groups.

E) A controlled experiment must have a control group and test group(s).

Explanation:

Answer:

B & E should be the answers

The rate of effusion of Argon here is 8.03 min

Data;

This law states that the rate of effusion of a gas is inversely proportional to the square root of it's molar mass.

[tex]R \alpha \frac{1}{\sqrt{M} }[/tex]

From this,

[tex]\frac{r_1}{r_2} = \frac{\sqrt{M_2} }{M_1}[/tex]

substituting the values and solving,

[tex]\frac{R_A_r}{12.7}= \frac{\sqrt{16} }{\sqrt{40} } \\ R_A_r = \frac{12.7*\sqrt{16} }{\sqrt{40} } \\R_A_r = 8.032min[/tex]

The rate of effusion of Argon here is 8.03 min

Learn more on Graham's law of effusion here;

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Answer: 3.5 moles of hydrogen gas will be produced.

Explanation:

The balanced chemical equation is:

[tex]2Fe+6HCl\rightarrow 2FeCl_3+3H_2[/tex]

As HCl gets completely used up, [tex]HCl[/tex] is the limiting reagent.

According to stoichiometry :

6 moles of [tex]HCl[/tex] produces =  3 moles of [tex]H_2[/tex]

Thus 7.0 moles of  [tex]HCl[/tex] produces=[tex]\frac{3}{6}\times 7.0=3.5moles[/tex]  of [tex]H_2[/tex]

 Thus 3.5 moles of hydrogen gas will be produced.

Answer:

3 grams??

Explanation:

I think this would be the answer you are looking for.

Answer:

when the valence (outermost) electrons of one atom are transferred permanently to another atom

Answer:

A fluke because it is an vertebrae

Explanation:

Answer: https://brainly.com/question/2426371

Explanation: Someone already answered this, click the link. YW! :))

Answer:

I think the answer is probably b

Answer:

A. in which oxidation numbers change

Explanation:

This is because in oxidation reduction reactions or redox reactions, involves the sharing or transfer of electrons between species and the oxidation numbers changes. There is change in electrons, ions or oxidation number by gaining or lossing electrons. Increase in oxidation number is an indication of oxidation while decrease in oxidation indicate reduction.

the first one is A covalent bond.

the second one is Answer: B Decomposition

Answer:

Overall enthalpy change for the formation of one mole nitric acid from nitrogen, hydrogen and oxygen, ΔH = -376 KJ

Note: the question is incomplete. The complete question is given below:

Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. In the first step, nitrogen and hydrogen react to form ammonia: N₂(g) + 3H₂(g)  → 2NH₃(g) ΔH = -92. kJ In the second step, ammonia and oxygen react to form nitric acid and water: NH3(g) + 2O2(g) → HNO3(g) + H2O(g) ΔH = -330. kJ Calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions. Round your answer to the nearest kJ.

Explanation:

From Hess's law of constant heat summation, the total enthalpy change for a reaction is the sum of all changes without regard to the number of multiple stages or steps involved in a reaction.

Enthalpy is a state function as it does not depend on the path taken to attain its value. Therefore, the summation of the enthalpy changes involved in the individual steps in the reaction of the formation of nitric acid will be equal to the enthalpy change of the overall reaction step.

For the first reaction step:

N₂(g) + 3H₂(g)  →  2NH₃(g) ΔH = -92. kJ

For the second reaction step:

NH₃(g) + 2O₂(g) → HNO3(g) + H2O(g) ΔH = -330. kJ

Overall reaction step:

[tex]\frac{1}{2}[/tex]N₂(g) + [tex]\frac{3}{2}[/tex]H₂(g) + 2O₂(g)  →  HNO₃ + H₂O  ΔH = ?

The overall reaction for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen shows that the first reaction step should be divided by 2

[tex]\frac{1}{2}[/tex]N₂(g) + [tex]\frac{3}{2}[/tex]3H₂(g)  →  NH₃(g) ΔH = -46. kJ

Overall enthalpy change, ΔH = ΔH₁ + ΔH₂

Overall enthalpy change,ΔH = (-46 KJ) + (-330 KJ)

Overall enthalpy change,ΔH = -376 KJ

Answer:

Ionic bond

CaO is an ionic bond. Two-element compounds are usually ionic when one element is a metal and the other is a non-metal. It is made up of one metal ion/cation(Ca^2+) and an non-metal ion/anion(O^2-).

Answer:

Nacl compound contain ionic bonds because sodium is metal and chlorin is nonmetal

Answer:

Classification is important because it allows scientists to identify, group, and properly name organisms via a standardized system (Linnaeus Taxonomy); based on similarities found in the organisms DNA/RNA (genetics), Adaptations (Evolution), and Embryonic development (Embryology) to other known organisms to better.

Hope I helped!!

The five kingdoms of classifications were animalia, plant, fungi, protista and monera. Later Archaebacteria was discovered and this led to the 3 kingdom classification animalia, plantae and protista.

There are different classifications for living things based on their nature, body and origin. The kingdom animalia includes  all the animals including human beings.

Kingdom plante includes all the plants and kingdom fungi, protista and monera are of microbes. Later the discovery and study of Archaebacteria proved that they exhibit similar body type and functions as bacterias.

After that, scientists turned into 3 kingdom classification, where all the prokaryotic organisms including protists, monera and fungi classified as one. The evolutional changes originated in them made this classification.

To find more on biological classification, refer here:

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Answer:

B

Explanation:

A isnt correct because animals have no emotions

C isnt correct because animals dont sleep all day

D isnt correct because not all organisms can swim or fly

B makes the most sense

Answer:

1.4×10⁸ g of CaO

Explanation:

We'll begin by converting 250 tonnes to grams (g). This can be obtained as follow:

1 tonne = 1×10⁶ g

Therefore,

250 tonne = 250 × 1×10⁶

250 tonne = 2.5×10⁸ g

Next, the balanced equation for the reaction.

CaCO₃ —> CaO + CO₂

Next, we shall determine the mass of CaCO₃ that decomposed and the mass CaO produced from the balanced equation. This can be obtained as follow:

Molar mass of CaCO₃ = 40 + 12 + (16×3)

= 40 + 12 + 48

= 100 g/mol

Mass of CaCO₃ from the balanced equation = 1 × 100 = 100 g

Molar mass of CaO = 40 + 16

= 56 g/mol

Mass of CaO from the balanced equation = 1 × 56 = 56 g

SUMMARY:

From the balanced equation above,

100 g of CaCO₃ decomposed to produce 56 g of CaO.

Finally, we shall determine the mass of CaO produced by the decomposition of 250 tonnes (i.e 2.5×10⁸ g) of CaCO₃. This can be obtained as follow:

From the balanced equation above,

100 g of CaCO₃ decomposed to produce 56 g of CaO.

Therefore, 2.5×10⁸ g of CaCO₃ will decompose to produce =

(2.5×10⁸ × 56)/100 = 1.4×10⁸ g of CaO.

Thus, 1.4×10⁸ g of CaO will be obtained from 250 tonnes (i.e 2.5×10⁸ g) of CaCO₃.

Answer:

130!!

Explanation:

Answer:

See explanation

Explanation:

In writing a chemical reaction equation, we must ensure that it is balanced. In a balanced chemical reaction equation, the number of atoms of each element on the left hand side of the reaction equation must be equal to the number of atoms of the same atom on the right hand side of the reaction equation.

Let us now consider the reaction of NaOH with water as follows;

2Na(s) + 2H2O(l) ------> 2NaOH(aq) + H2(g)

For the reaction of Magnesium metal and HCl we have;

Mg(s) + 2HCl(aq) -------> MgCl2(aq) + H2(g)

Answer:

I think the answer is X

Explanation:

X is a variable and variables stand for the unknown

Answer:

d

Explanation:

Answer:

hopen it helps soo much thanks for the points

Answer:

Kc = 1.09x10⁻⁴

Explanation:

HF = 1.62g

H₂O = 516g

F⁻ = 0.163g

H₃O⁺ = 0.110g

To solve this question we need to find the moles of each reactant in order to solve the molar concentration of each reactan and replacing in the Kc expression. For the reaction, the Kc is:

Kc = [H₃O⁺] [F⁻] / [HF]

Because Kc is defined as the ratio between concentrations of products over reactants powered to its reaction coefficient. Pure liquids as water are not taken into account in Kc expression:

[H₃O⁺] = 0.110g * (1mol /19.01g) = 0.00579moles / 5.6L = 1.03x10⁻³M

[F⁻] = 0.163g * (1mol /19.0g) = 0.00858moles / 5.6L = 1.53x10⁻³M

[HF] = 1.62g * (1mol /20g) = 0.081moles / 5.6L = 0.0145M

Kc = [1.03x10⁻³M] [1.53x10⁻³M] / [0.0145M]

Answer:

A. Dalton's model

Explanation:

Dalton's model was discarded as a result of Rutherford's model.

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[tex]\small\sf\:\:\:\:\:\:\:\:{:}\:\Longrightarrow{\bold{\pink{\sf{Thomson's \:model}}}}[/tex]

Answer:

The chemical compound Mg(NO3)2, also known as magnesium nitrate, is very soluble, especially in water.

Answer:

1 Ca3(PO4)2+ 6 NaCl ---------> 2 Na3PO4 + 3 CaCl2

Answer:

In nuclear fission, an unstable atom splits into two or more smaller pieces that are more stable, and releases energy in the process. The fission process also releases extra neutrons, which can then split additional atoms, resulting in a chain reaction that releases a lot of energy.

Explanation:

Answer:

The bones of the skull and spinal column

Explanation:

The central nervous system is better protected than any other system or organ in the body. Its main line of defense is the bones of the skull and spinal column, which create a hard physical barrier to injury.

Answer:

The Central Nervous System (CNS)