What is the SI unit of time?
OA.
second
OB.
minute
OC. hour
OD. day
Res

Answer:

metal oxide +hydrogen gas

Answer:

chu papi

Explanation:

This question is asking for a method for the determination of the freezing point in a solution that does not have a noticeable transition in the cooling curve, which is basically based on a linear fit method.

The first step, would be to understand that when the transition is well-defined as the one on the attached file, we can just identify the temperature by just reading the value on the graph, at the time the slope has a pronounced change. For instance, on the attached, the transition occurs after about 43 seconds and the freezing point will be about 4 °C.

However, when we cannot identify a pronounced change in the slope, it will be necessary to use a linear fit method (such as minimum squares) to figure out the equation for each segmented line having a significantly different slope and then equal them so that we can numerically solve for the intercept.

As an example, imagine two of the segmented lines have the following equations after applying the linear fit method:

[tex]y=-3.5 x + 25\\\\y=-0.52 x + 2[/tex]

First of all, we equal them to find the x-value, in this case the time at which the freezing point takes place:

[tex]-3.5 x + 25=-0.52 x + 2\\\\-3.5 x+0.52 x =2-25\\\\x=\frac{-23}{-2.98}=7.72[/tex]

Next, we plug it in in any of the trendlines to obtain the freezing point as the y-value:

[tex]y=-3.5 (7.72) + 25\\\\y = 1.84[/tex]

This means the freezing point takes place after 7.72 second of cooling and is about 1.84 °C. Now you can replicate it for any not well-defined cooling curve.

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Answer:

ooooooooh .,.,.,.,.,.,

Answer:

True

TruePhysical change – A change in the size, shape, color, or state of matter of a substance. No new substance is produced.

Explanation:

83.6-24.2= 59.4 which is the change in heat

an ionic compound is made of two or more elements held by a strong electrostatic force. metal atoms lose electrons to become positive ions, and non metals gain electrons to become negative ions. ionic bonding occurs between metals and non metals

Answer:

We can do an experiment with vinegar to see what happens to the calcium in an eggshell when it is exposed to an acid.

There are different ways of extraction. The best way to begin an extraction to separate the amine from the mixture is to extract with dilute NaOH.

NaOH is known to be the most common compound that is used to convert a carboxylic acid into its more water-soluble ionic carboxylate form.

But if  the mixture has a compound that you want, and that can react with NaOH, another milder base such as sodium bicarbonate is preferably used.

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A mixture of solids containing a ketone, a carboxylic acid, and an amine, are dissolved in DCM. What is the best way to begin an extraction in order to separate the carboxylic acid from the mixture?

A) Extract with dilute NaOH

B) Extract with dilute HCl

C) Extract with dichloromethane

D) Extract with water

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I don't think the answer is in one of the options- unless I am reading it wrong and there is a 'V' option.

The volume (V) of gas increases when the pressure of the gas decreases assuming all the other variables are held constant.

I hope this helps!

Using melting and boiling temperature, hardness and electric current passing testing.

Ionic solids are materials that have a strong bond between their ions, thus producing well-defined shapes.

In addition, due to this strong attraction, the boiling and melting temperatures of these materials are very high, in addition to the resistance to breakage presented by them.

Finally, ionic solids are also excellent conductors of electricity.

So, their properties used to determine whether or not they are ionic solids are  melting and boiling temperature, hardness and electric current passing testing.

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To extract hydrogen from water, researchers insert two electrodes across the water and pass current, which can separate the hydrogen from water. The process called electrolysis of water. ... An electric field applied through the cobalt oxide to water molecules resulted in the electrolysis of water

Hydrogen gas is an environment-friendly fuel — it produces water on combustion in the presence of oxygen. ... To extract hydrogen from water, researchers insert two electrodes across the water and pass current, which can separate the hydrogen from water. The process called electrolysis of water.

The energy taken in to break the bond is greater than the energy released after the bond is made therefore the reaction is endothermic.

A plot of energy against time is called a reaction profile. The hump in the plot is known as the activation energy of the reaction. It stands as the energy barrier between reactants and products.

Looking at the reaction profile as shown, we can see that more energy is taken in to break the bonds than energy that is given out after making the bonds hence the reaction is endothermic.

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Answer:

the answer is c

Explanation:

usa test prep says so!

Answer:,   Correct option is    0.288m/s

Explanation:    

The relationship between the velocity of the wave, its wavelength and frequency is given by the formula

Wavelengthλ=

Frequency(ν)

Speed(v)

​

,

where, v - velocity of the wave

           λ - wavelength of the wave

          f - frequency of the wave.

In the question it is given that the frequency is 4.8 Hz and the wavelength is 6.0 cm, that is, 0.06 meters.

The velocity of the sound is calculated as follows.

v=f×λ=4.8 Hz×0.06 m=0.288 m/s

Hence, the speed of the water wave is 0.288 m/s.

Answer:

River esk the third one is righttt

Answer:

=> moles = Given mass/molar mass

=> 0.787 = Given mass/(39 + 12 + 14)

=> 0.787 = Given mass/65

=> mass = 0.787 × 65

=> mass = 51.155 g

Answer:

Explanation:

I hope this helps

Answer:

Explanation:wwwwwwwwwwwwwwwwwwww

The theoretical yield of acetate is 2607 g. The actual yield of acetate is 1066.8 g. The percentage yield of acetate is 41%.

If 1 mole of vinegar contains 6.02  x 10^23 particles

x moles of vinegar contains 9.02 x 10^24 particles

x = 1 mole x 9.02 x 10^24 /6.02 x 10^23

x = 15 moles of vinegar

The reaction is as follows;

2HC2H3O2 + CaCO3 -----> Ca(C2H3O2)2 + H2O + CO2

Since 2 moles of vinegar reacts with 1 mole of carbonate

x moles of vinegar reacts with 16.5 moles of carbonate

x =  2 moles x 16.5 moles/ 1 mole

x = 33 moles of vinegar

We can see that the vinegar is the reactant in excess hence the carbonate is the limiting reactant.

Theoretical yield = 16.5 moles x 158 g/mol = 2607 g

Actual yield = 6.35 moles  x 158 g/mol = 1066.8 g

Percent yield = 1066.8 g/2607 g × 100/1

= 41%

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Answer:

No it has not.

Explanation:

The actual chemical compound has not changed, the materials have mixed but no reaction has taken place. Blowing the bubbles causes a physical change. Hope this helped!

Mixing soap and water and forming bubbles is a physical change as there is no change in composition.

Physical changes are defined as changes which affect only the form of a substance but not it's chemical composition. They are used to separate mixtures in to chemical components but cannot be used to separate compounds to simpler compounds.

Physical changes are always reversible using physical means and involve a change in the physical properties.Examples of physical changes include melting,boiling , change in texture, size,color,volume and density.Magnetism, crystallization, formation of alloys are all reversible and hence physical changes.

They involve only rearrangement of atoms and are often characterized to be changes which are reversible.

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In this case, the problem is asking for the balance of a redox reaction in acidic media, in which nickel is reduced to a metallic way and nitrogen oxidized to an ionic way.

Thus, according to the given information, it turns out possible for us to balance this equation in acidic solution by firstly setting up the half reactions:

[tex]Ni^{2+}+2e^-\rightarrow Ni^0\\\\N^{3-}H_4^++3H_2O\rightarrow N^{5+}O_3^-+8e^-+10H^+[/tex]

Next, we cross multiply each half-reaction by the other's carried electrons:

[tex]8Ni^{2+}+16e^-\rightarrow 8Ni^0\\\\2N^{3-}H_4^++6H_2O\rightarrow 2N^{5+}O_3^-+16e^-+20H^+[/tex]

Finally, we add them together to obtain:

[tex]8Ni^{2+}+2N^{3-}H_4^++6H_2O\rightarrow 8Ni^0+2N^{5+}O_3^-+20H^+[/tex]

Which can be all simplified by a factor of 2 to obtain:

[tex]4Ni^{2+}+N^{3-}H_4^++3H_2O\rightarrow 4Ni^0+N^{5+}O_3^-+10H^+\\\\4Ni^{2+}(aq)+NH_4^+(aq)+3H_2O(l)\rightarrow 4Ni(s)+NO_3^-(aq)+10H^+(aq)[/tex]

Hence, the coefficients in front of Ni and H⁺ are 4 and 10 respectively.

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Answer:

you lift my feet off the ground spin me around you make me crazier crazier

Answer:

composition of an element

Answer:

49.979

Explanation:

Answer:

A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium.

Explanation:

While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefore, the oscillating material does not move far from its initial equilibrium position.

--------------

hope this helped!

✼-answers by brookeangelx

The wave transmits energy from one point to another in the form of signals. Some waves require a medium for propagation while some others does not require a medium for the propagation.

The mechanical wave is defined as the wave which involves the oscillation of matter and it is responsible for the transfer of energy through a medium. These types of waves does not need a medium for propagation.

The mechanical waves cannot travel through vacuum. Some of the examples of mechanical waves are sound waves, water waves, seismic waves, etc. These waves are not capable of transmitting its energy through a vacuum.

The sound wave is a mechanical wave and the medium which it propagates can be solid, liquid or gas. It can travel fastest in solids and slower in gases.

Thus mechanical wave is an oscillation of matter.

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Taking into account the definition of enthalpy of a chemical reaction, the quantity of heat released when 5.87 moles of CH₄ are burned is 4,707.74 kJ.

The enthalpy of a chemical reaction as the heat absorbed or released in a chemical reaction when it occurs at constant pressure. That is, the heat of reaction is the energy that is released or absorbed when chemicals are transformed into a chemical reaction.

The enthalpy is an extensive property, that is, it depends on the amount of matter present.

In this case, the balanced reaction is:

CH₄ (g) + 2 O₂ (g) → CO₂ (g) + 2 H₂O(g)

and the enthalpy reaction ∆H° has a value of -802 kJ/mol.

This equation indicates that when 1 mole of CH₄ reacts with 2 moles of O2, 802 kJ of heat is released.

When 5.87 moles of CH₄ are burned, then you can apply the following rule of three: if 1 mole of CH₄ releases 802 kJ of heat, 5.87 moles of CH₄ releases how much heat?

[tex]heat=\frac{5.87 molesof CH_{4}x802 kJ}{1 mol of CH_{4} }[/tex]

heat= 4,707.74 kJ

Finally, the quantity of heat released when 5.87 moles of CH₄ are burned is 4,707.74 kJ.

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Answer:

3

Explanation:

Here's the balanced equation;

C2H4 + 3O2 → 2CO2 + 2H2O

C ⇒2                          C ⇒1 x 2 = 2

H ⇒4                          H ⇒2 x 2 = 4

O ⇒3 x 2 = 6             O ⇒ (2 x 2) + (2 x 1) = 6

The coefficient that has been added as the coefficient to O2 is 3.

C2H4 + 3O2 → 2CO2 + 2H2O.

the given equation has 2oxygen atoms on the reactant side and 3 oxygen atoms on the product side

so to make it equal we have to add 3 as coefficient of O2  on the reactant side.

Therefore the correct answer to the equation C2H4 + 3O2 → 2CO2 + 2H2O is 3.

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Answer:A versatile Ideal Gas Laws calculator with which you can calculate the pressure, volume, quantity (moles) or temperature of an ideal gas, given the other three. Free online gas law calculator a.k.a. PV = nRT calculator which accepts different input metric units such as temperature in celsius, fahrenheit, kelvin; pressure in pascals, bars, atmospheres; volume in both metric and imperial units ...

From the data obtained from the tests, the actual boiling point lies between 34°C and 40°C.

The boiling point of a substance is the temperature at which the pressure of the substance becomes equal to atmospheric pressure. Pure substances have a sharp boiling point while impure substances boil over a temperature range.

In this case, the boiling point of the substance after 10 tests is obtained as 37+/−3°C. This implies that the actual boiling point lies between 34°C and 40°C.

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Answer:

The answer is A and C.

Explanation:

The reactants in the process of cellular respiration are oxygen and glucose, respectively. It is ATP that serves as the primary product of cellular respiration, with carbon dioxide and water serving as waste products.

Sugar is a glucose.

Oxygen and glucose are the two  substances that are reactants in the chemical reactions of cellular respiration. Therefore, the correct options are options A, C.

Through the process of cellular respiration, organisms mix oxygen with food molecules, directing the chemical energy contained in these substances towards life-sustaining processes while excreting carbon dioxide and water as waste. Foods are broken down by microorganisms that do not require oxygen in a process known as fermentation.

Adenosine triphosphate (ATP), an energy-rich compound that absorbs the chemical energy generated by the decomposition of food molecules then releases it to power other cellular functions, is one goal of the breakdown of foodstuffs. ATP is created when the energy found inside chemical bonds is converted from one form to another. Oxygen and glucose are the two  substances that are reactants in the chemical reactions of cellular respiration.

Therefore, the correct options are options A, C.

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