25 points!!! What’s the answer???

Answer:

C. The researcher exercises direct control over at least one variable.

Explanation:

Your answer should be C. The researcher exercises direct control over at least one variable.

I hope it helps! Have a great day!

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The rate of reaction of the magnesium ribbon in the dilute hydrochloric acid is 0.067 g/s.

Rate of reaction is the rate at which a reaction takes place. It is proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time.

Mg(s) + 2HCI = MgCl2(aq) + H2(g)

Rate of reaction = mass of magnesium reacted/time taken

Rate of reaction =  2 g /30 s

Rate of reaction =  0.067 g/s

Thus, the rate of reaction of the magnesium ribbon in the dilute hydrochloric acid is 0.067 g/s.

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Answer:

About 64 grams of KClO₃.

Explanation:

Potassium chlorate dissociates according to the equation:
[tex]\displaystyle 2\text{KClO$_3$} \xrightarrow{\text{heat}} 2\text{KCl} + 3\text{O$_2$}[/tex]

To determine the amount of KClO₃ necessary to produce 25 grams of O₂, we can convert grams of O₂ to moles; moles of O₂ to moles of KClO₃;  and finally to grams of KClO₃.

The molecular weights of O₂ and KClO₃ are 16.00 g/mol and 122.55 g/mol.

Hence:

[tex]\displaystyle 25\text{ g O$_2$} \cdot \frac{1\text{ mol O$_2$}}{32.00\text{ g O$_2$}} \cdot \frac{2\text{ mol KClO$_3$}}{3\text{ mol O$_2$}} \cdot \frac{122.55\text{ g KClO$_3$}}{1\text{ mol KClO$_3$}} = 64\text{ g KClO$_3$}[/tex]

In conclusion, about 64 (to two significant digits) grams of KClO₃ is needed.

The volume of gas occupied by 11 grams of nitrogen dioxide gas at STP is 5.15 L.

Ideal gas equation of any gas will be writen as:

PV = nRT, where

P = standard pressure = 1 atm

V = volume = ?

R = universal gas constant = 0.082 L.atm/K.mol

T = standard temperature = 273K

n is the moles of gas which can be calculated by using below equation as:

n = W/M, where

W = given mass = 11g

M = molar mass = 46 g/mol

n = 11 / 46 = 0.239mol

On putting values on the above equation, we get

V = (0.23)(0.082)(273) / (1) = 5.15 L

Hence required volume of gas is 5.15 L.

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Explanation:

Constructive interference occurs when the maxima of two waves add together (the two waves are in phase), so that the amplitude of the resulting wave is equal to the sum of the individual amplitudes. Equivalently, the minima of the waves would be aligned.

Answer:

60 days

Explanation:

2500 = 40000 ( 1/2) ^n

n = 4 half lives

4 half lives * 15 days/ halflife = 60 days

Alkali metals require least amount of ionization energy.

Peaky Blinder fan? haha

The solution would be like this for this specific problem:

Moles of carbon = 58.8 / 12 = 4.9

Moles of hydrogen = 9.8 / 1 = 9.8

Moles of oxugen = 31.4 / 16 m= 1.96

Ratio 4.9 / 1.96 = 2.5 9.8 / 1.96 = 5.0 1.96 / 1.96 = 1

Simplest formula = C5H10

I hope this helps and if you have any further questions, please don’t hesitate to ask again.

Answer:

please the answer Is false

Based on the data provided, the equation of the reaction is:

Enthalpy of neutralization is the heat change when one mole of hydrogen ions from an acid reacts with one mole of hydroxide ions from an alkali to produce one mole of water.

The equation of the reaction of KOH and HNO3 is given below:

[tex]KOH + HNO_3 \rightarrow KCl + H_2O[/tex]

1 mole of KOH reacts with 1 mole of HNO3 to produce 1 mole of water.

Volume of KOH = 30 mL = 0.03 L

moles of KOH = 0.03 × 0.234 = 0.00702 moles

Therefore, 0.00702 moles of water are produced

Heat produce = mass × specific heat × temperature difference

Volume of solution = 60 mL

density of solution = 1.0 g/mL

mass of solution = 60 mL × 1.0 g/mL = 60 g

Heat produced = 60 × 4.18 × 5.6

Heat produced = 1404.48 J

Enthalpy of neutralization = 1404.48 J/0.00702 moles

Enthalpy of neutralization = 200068.37 J/mol

Enthalpy of neutralization = 200 kJ/mol

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Answer:

A - Cinder cone

B - Shield

C - Composite

Explanation:

Cinder cone volcanoes are formed when the volcano explodes and all the lava soldifies and falls steeply upon the sides of the mountain and forms cinders.

Shield volcanoes form when a centralized vent produces low-viscosity flows over a long period of time

Composite volcanoes are also called stratovolcanoes. They form when different types of eruptions deposit different materials around the sides of a volcano. Alternating eruptions of volcanic ash and lava cause layers to form. Over time these layers build up.

Answer:

Answer:A - Cinder coneB - Shield C - CompositeExplanation:Cinder cone volcanoes are formed when the volcano explodes and all the lava soldifies and falls steeply upon the sides of the mountain and forms cinders. Shield volcanoes form when a centralized vent produces low-viscosity flows over a long period of time Composite volcanoes are also called stratovolcanoes. They form when different types of eruptions deposit different materials around the sides of a volcano. Alternating eruptions of volcanic ash and lava cause layers to form. Over time these layers build up.:

Answer:

i dont know, i wish i could help

Explanation:

Answer:

Combustion. It is combustion since we assume that it is in a rigid container and Na reacts with oxygen gas

Answer:

6 moles

Explanation:

First find the balanced equation for the rxn

N2     + 3 H2   ===>  2  NH3

each mole of N2  requires  3 moles of Hydrogen

so 6 moles of H needed

Answer:

3

Explanation:

7.02     three sig digits

Apply Gay lussac's law

Answer:

CS2 + 3O2 -> CO2 + 2SO2

Explanation:

Answer:

The specific heat capacity is the heat or energy required to change one unit mass of a substance of a constant volume by 1 °C. The formula is Cv = Q / (ΔT ⨉ m)

Answer:

The ammonia molecule is a trigonal pyramidal and has 4 sp3 orbitals

Explanation:

Nitrogen has 5 valence electrons, Hydrogen takes up 3 bonds and there's a lone pair on top, and the gemoetry is structured in a way so the hydrogen atoms are facing down away from the lone pair and evenly spaced out between the other hydrogens.

The molarity of the sample of the salt dissolved in the solution is determined as 0.1 M.

The molarity of the sample is the number of solutes dissolved in liters solution.

molarity = number of moles/Liters of solution

molarity = 0.2 moles / 2L

molarity = 0.1 M

Thus, the molarity of the sample of the salt dissolved in the solution is determined as 0.1 M.

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Sovereignty is the ultimate authority, in the decision-making process of the state and in the maintenance of law and order.

Sovereignty refers to authority within an individual consciousness or territory. Sovereignty entails hierarchy within the state and also for external autonomy for states.

So we can conclude that sovereignty is the ultimate authority, in the decision-making process of the state and in the maintenance of law and order.

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Answer:

1630.2 j

Explanation:

100 gm * 4.18 J/gm-C  * ( 25.9-22 C ) = 1630.2 j

In redox reactions, an oxidation half reaction shows the oxusetoon occurring while the reduction half reaction shows the reduction occurring in the overall reaction.

Redox reactions are reactions in which oxidation and reduction reactions occur together to the same extent.

A redox reaction can be split into two half oxidation and reduction reactions.

The half reactions of the given reactions are shown below:

Overall reaction;

[tex]A. Mg(s) + CoBr_2(aq) ⟶ MgBr_2(aq) + Co(s) \\ [/tex]

Oxidation half reaction:

[tex]Mg (s) ---> Mg ^{2+}(aq)[/tex]

Reduction half reaction:

[tex]Co^{2+} (aq) ---> Co (s)[/tex]

B. Overall reaction

[tex]Cu(s) + 2AuCl(aq) ⟶ CuCl_2(aq) + 2Au(s) \\ [/tex]

Oxidation half reaction:

[tex]Cu(s) ---> Cu^{2+}(aq)[/tex]

Reduction half reaction:

[tex]2Au^{+}(aq) ---> 2 Au (s)[/tex]

Therefore, redox equations can be spilt into oxidation and reduction half reactions.

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The Ksp shows the extent of solubility of a substance in another. The solubility of the compound is 1.2 * 10^-7 M.

The term solubility shows the extent to which a substance dissolve in solution. The solubility of a substance is often typified by the Ksp of the substance.

Now;

ScF3(s) ⇄Sc^+(aq) + 3F^-

Ksp = [Sc^+] [F^-]^3

Ksp = x (3x)^3

Ksp = 27x^4

x = 4√5.81×10^−24/27

x = 1.2 * 10^-7 M

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Answer:

so the answer is A 5.199mol please. rate. me brainliest. if its. correct

Explanation:

N=nL

[tex]3.131 \times {10}^{24} = n \times 6.022 \times {10}^{23} \\n = \frac{3.131 \times {10}^{24} }{6.022 \times {10}^{23} } \\ n = 5.199mol[/tex]

Answer:

Thick layer of body fat for food storage and insulation

Explanation:

Polar bears store food for themselves and so do camels. Option B is not correct because bears do not definitely have small surface area and even if camels do they do not need to reduce heat loss because they stay in the deserts. For option C polar bears have thick fur and much body fat to protect itself from the cold. Lastly D cannot be true because camels don't normally have large feet they have small padded foot.

The curious and observant are the words in the story which helps the reader understand the meaning of the word avid.

This refers to when an individual is very enthusiastic or interested in something.

In paragraph 1 , the words which makes us understand the word 'avid' is the character being curious and observant which shows there is interest.

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