what is a null hypothesis

Answer:

2Ca + O₂ → 2CaO

Explanation:

Cuando el Calcio (Ca) reacciona con oxígeno (O₂) se produce cal (CaO). La cal es un sólido inodoro de color blanco a grisáceo. La cal es un óxido que se encuentra presente en el cemento y su cuantificación permite determinar la calidad y el tipo de cemento a utilizar.

La reacción que describe el proceso anterior es:

Ca + O₂ → CaO

Para balancear los oxígenos, se deben poner 2 CaO como producto:

Ca + O₂ → 2CaO

Para balancear los calcios, se pone como coeficiente del Ca un 2:

Esta última es la reacción que describe el proceso anterior

Answer:

The California Condor is on the verge of extinction. There were three individuals, all males, known to be living free in late 1986. That was a drop from fifteen wild birds (including five breeding pairs) known to have been present in 1984. Twenty-one condors were also alive in captivity toward the end of 1986.

Explanation:

Explanation:

taiga the largest land well forest

Answer: –1,267.2 kJ

Explanation: B on edge, thank me later ;-)

–1,267.2 kJ is the enthalpy of the given reaction. Therefore, the correct option is option A among all the given options.

Enthalpy is a thermodynamic system's internal energy total as well as the volume times pressure ratio. Enthalpy is a property or state function that resembles energy; it has the same dimensions as energy and is therefore measured in joules or ergs. The value of enthalpy is solely dependent on the temperature, pressure, as well as composition of the system, not on its history.

The shift in the internal energy equals equivalent to the heat transmitted to, much less than the jobs completed by, the system, in accordance with the principle of energy conservation. The enthalpy change is precisely equal to the heat transmitted to the system if the sole work performed is a change in volume at constant pressure.

ΔH = ΔH for product - ΔH for reactant

     = 3,572.1 kJ –1,267.2 kJ

    = –1,267.2 kJ

Therefore, the correct option is option A.

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Answer:

b- freezing water

Explanation:

Solid<liquid<gas is the general rule for entropy increase

Freezing water would change the phase from liquid to solid which would lead to less entropy

Answer:

60g or 61.28g

Explanation:

Trust me on this I had the same problem as you

Answer:

There are 15 protons in phosphorous.

~Hoped this helped~

~Brainiliest?~

Answer:

gravity pulls on the earth and putts it in orbit around the sun

Explanation:

Answer:I just want points

Explanation:because I need them for future questions

Answer:

12.1-M requires less volume of stock solution.

Explanation:

Hello there!

In this case, according to the foundations of dilution processes, it turns out convenient to remember that the moles of the solute before and after the dilution remains the same; for that reason we use the following equation:

[tex]M_1V_1=M_2V_2[/tex]

Relating the initial and final molarities and volumes. Now, it is seen that V2 is 10.0 mL and M2 is 1.0 M, which means that if we solve for V1 for 12.1 M and 6.0 M, we obtain the following volumes:

[tex]V_1=\frac{M_2V_2}{M_1} \\\\V_1^{12.1M}=\frac{1.0M*10.0 mL}{12.1M}=0.826mL\\\\V_1^{6.0M}=\frac{1.0M*10.0 mL}{6.0M}=1.67mL[/tex]

Therefore, since the 12.1-M solution requires less volume of stock solution, it makes sense to use this one as the initial solution.

Best regards!

Answer:

2 boron and 3 sulfur

Explanation:

The subscript/ number behind and under is a subscript this tells you how many atoms there are

Answer:

The radioactive isotopes within these brains typically record the ages of the grains-not the time when the sedimentary rock was formed, making it difficult to date using radiometric dating. The half-life of U-235 is 704 million years.

Explanation:

hope this helps but if i'm wrong then i'm sorry..

Answer:

D

Explanation:

Very old rocks would be been formed before said isotopes with short half-lives. We're thinking of a very long geological time. The original rock might be rock C, then years and years later rock Y would be measured. Y can't match C since there's too much unknowns in between.

Answer:

algebra

Explanation:

The parallax formula states that the distance to a star is equal to 1 divided by the parallax angle,  

p

, where  

p

is measured in arc-seconds, and  

d

is parsecs.

I'm positive that the answer is trigonometry.

Refer to the following passage that I got from the Edg assignment.

"How then do astronomers measure the distance of stars? The parallax, considered very accurate, is one method used by astronomers to measure the distances to nearby stars. The diameter of the earth’s orbit around the sun is about 300 million km. By observing a star one day and then again six months later, these scientists will be able to observe differences in the star the two times it was observed. Using trigonometry, these different angles yield the distance of how far away a star is."

Answer:

Option C, the shower not sprayed with any mildew-preventing spray is most likely be the control group in this  study

Explanation:

Complete question

Mildew is a fungus that grows in wet areas and can slowly grow from microscopic to large stains in showers and sinks. Researchers are studying different sprays that could be used to slow down the growth of mildew. They set up different showers that are exactly the same and expose them each to water with the same microscopic amount of mildew. They then spray some of the showers with mildew-preventing sprays and observe how fast mildew grows over time. Which show would most likely be the control group in this study? A- the shower sprayed with many test sprays B- the shower not exposed to any mildew at all C- the shower not sprayed with any mildew-preventing spray D- the shower sprayed with a test spray that is already known to work

Solution

In any experiment, a control group is a group of participants that is not exposed to any treatment so that it can be compared with the experimental group on which the treatment is applied/given.

In this case - experimental group are the stained showers that are subjected to the different types of mildew test sprays while the control group is the the shower not sprayed with any mildew-preventing spray.

Hence, option C is the correct answer

Answer:

The isopropanol evaporated while the water did not because the molecules don't stick together as strongly as the molecules in the water do. The water would need more energy transferred in, in order to evaporate.

Explanation:

The isopropanol evaporates and the water does not because the heat capacity and the latent heat of isopropanol is far lesser than that of water.

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Answer:

they reduce viral transmission

They prevent asymptomatic spread

You're protecting others from illness.

They're mandated by law in some states

They're good hygiene in general

Answer: A reaction which occurs when equivalent quantities of H" (or [tex]H_{3}O^{+}[/tex]) and OH" are mixed is a neutralization reaction.

Explanation:

When acid and base chemically combine together to form sat and water then it is know as neutralization reaction.

An acidic substance gives hydrogen ions [tex](H^{+})[/tex] on dissociation and a basic substance gives hydroxide ions [tex](OH^{-})[/tex] on dissociation.

For example, [tex]H^{+} + OH^{-} \rightarrow H_{2}O[/tex] is a neutralization reaction where an acid and base are mixed together to form water.

No salt is formed as because here the reactants are not present as compounds.

In a hydrolysis reaction, water molecule(s) is added to the reactant molecules.

For example, [tex]CH_{3}COOCH_{3} + H_2O \rightarrow CH_{3}COOH + CH_{3}OH[/tex]

Oxidation is the process of addition of oxygen to a molecule and removal of hydrogen.

Reduction is the process of addition of hydrogen in a compound and the removal of oxygen atom.

Therefore, we can conclude that reaction which occurs when equivalent quantities of H" (or [tex]H_{3}O^{+}[/tex]) and OH" are mixed is a neutralization reaction.

Answer:

3.02 X1023 atoms Ag limol. - - 0.50 1 moles. 6.02241023 atoms.

Answer:

b)6.2 grams

Explanation:

Recall that percentage yield =

actual yield/theoretical yield * 100/1

theoretical yield = 8.2 grams

percentage yield = 75%

Let the actual yield be x

Hence;

75 = x/8.2 * 100

75 = 100x/8.2

75 * 8.2 = 100x

x = 75 * 8.2/100

x = 6.15 g

x = 6.2 g

75 =

Answer:

1160mg

Explanation:

Molarity = number of moles ÷ volume

According to the information in the question, molarity = 1.25 M, volume = 18.0 mL = 18/1000 = 0.018L

M = n/V

n = M × V

n = 1.25 × 0.018

n = 0.0225moles.

Using mole = mass/molar mass, to find the mass of lithium phosphide (Li3P)

Molar mass of Li3P = 6.9(3) + 31 = 51.7g/mol

mole = mass/molar mass

0.0225 = mass/51.7

mass = 1.16grams.

In milligrams (mg), mass of Li3P = 1.16 × 1000 = 1160mg

Answer:

In simple words, Sharks have the ability to enter a trance state. Whenever a shark is flipped upside around it enters a trance-like experience known as tonic immobilization.

That's why, when certain researchers are operating on saw fish with in ocean, they often turn them over. Otherwise, there is a chance that the fish might start panicking and the work of scientist will get tougher.

Answer:

2 moles H

2

Explanation:

Your tool of choice here will be the mole ratio that exists between zinc metal,  

Zn

, and hydrochloric acid,  

:HCl

, in the balanced chemical equation.

Zn

(s]

+

2

HCl

(aq]

→

ZnCl

2(aq]

+

H

2(g]

↑

⏐

You're dealing with a single replacement reaction in which zinc displaces the hydrogen from hydrochloric acid. The products of the reaction are aqueous zinc chloride and hydrogen gas.

Now, as you can see from the balance chemical equation, a  

1

:

2

mole ratio exists between the two reactants.

This tells you that in order for the reaction to take place, you need to have twice as many moles of hydrochloric acid as you do of zinc metal.

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At the same time, you have a  

2

:

1

mole ratio between hydrochloric acid and hydrogen gas.

This means that the reaction will always produce half as many moles of hydrogen gas as you have moles of hydrochloric acid.

Since you know that  

4

moles of hydrochloric acid are taking part in the reaction, and assuming that you have enough zinc metal so that it doesn't act as a limiting reagent, you can say that the reaction will produce

4

moles HCl

⋅

1 mole H

2

2

moles HCl

=

2 moles H

2

Explanation:

Answer:

1) Hom DOMINANT

2) Hom recessive

3) Hetero DOMINANT

4) Hom DOMINANT

5) Hetero DOMINANT

6) Hom recessive

Explanation: