Fill in the blank with the correct number to balance the equation: 4AI +____O2 → 2Al₂O3.
(Enter only a whole number.)

Copper-plating is a chemical change in which copper ions become neutral copper atoms by accepting electrons which then are deposited on the material to be coated.

copper-plating?Copper-plating is the process by which a layer of copper is used to coat another material using the process of electrolysis.

At the molecular level, copper ions in solution accept electrons to become neutral copper atoms which then are deposited on the material, thereby coating.

This is an example of a chemical change since it us not easily reversible and new products are formed.

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Compared to infrared radiation, an electromagnetic wave that has a lower frequency will also have a longer wavelength and equal speed

Electromagnetic waves or EM waves are waves that are created as a result of vibrations between an electric field and a magnetic field.

It can be also defined as waves are composed of oscillating magnetic and electric fields.

One important feature fo electromagnetic radiation is that all have the same speed in vacuum, c, in vacuum, which is the speed of light.

Since, the speed, wavelength and frequency of the waves are related you can infere any of them when the other two are known.

The equation is:

speed = frequency × wavelength

   s     =          ν        ×      λ

   c     =          ν        ×      λ      . . . for the specific case of electromagnetic radiation

That inverse relation between frequency and wavelength, where the speed is the constant, shows that the lower the frequency the longer the wavelength.

Therefore,  the correct statment is that an an electromagnetic wave that has a lower frequency will also have a longer wavelength and equal speed (option B).

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Answer:

Explanation:

Ok so Proust's Law, better known as the Law of Definite Proportions, states that the components of a compound always exist in a fixed ratio. This means that it does not matter what the source of the components are nor the coefficients in front of them. The ratio your teacher is referring to is most likely mass percent/ percent composition. This ratio is the amount of the component over the amount of the entire compound times 100%.

*I am not very familiar with this law so please do with my answers what you will :)*

7.)

First, you want to find the percent composition (aka mass composition) of Na in NaCl.

 45.89 g Na
---------------------  x 100%  =  39.3%
116.89 g NaCl

So, there must be 39.3% sodium in NaCl. You can find how much chlorine is in NaCl by subtracting that percent by 100 (to find the percent composition of chlorine) then multiplying it by the mass.

100% - 39.3% = 60.7%

60.7% / 100 = 0.0607

116.89 g NaCl x 0.0607 = 70.91 g Cl₂

You could also just subtract the mass of sodium from the mass of sodium chloride to find the mass of chlorine.

116.89 g NaCl - 45.89 g Na = 71 g Cl₂

8.)

10.57 g Mg + 6.96 g O₂ = 17.53 g MgO

  6.96 g O₂
---------------------  x 100%  = 39.7% O₂
17.53 g MgO

9.)

6.46 g Pb = 1 g O₂

68.54 g Pb  =  28.76 g O₂

68.54 g Pb / 28.76 g O₂ = 2.83 g ≠ 6.46 g

No, the two samples are not the same because the proportion of lead to oxygen is not the same for both samples. In the first sample, there is 6.46 g lead for every oxygen. In the second sample, there is 2.38 g lead for every oxygen.

Answer:

6.022 x 10²³

Explanation:

The number of atoms =  the number of moles x with the Avogadro's number.

(The Avogadro's number is 6.022 x 10²³ atoms / moles)

number of atoms = 1.00 moles x 6.022 x 10²³ atoms / mole

number of atoms =  6.022 x 10²³ atoms

(There is no need to simplify?) = 6.022 x 10²³

(ps. This is my first time doing this question so im sorry if i got it wrong

(つ﹏⊂)

Taking into account the reaction stoichiometry, the mass of silver(I) chloride formed is 930.37 grams.

In first place, the balanced reaction is:

2 AgNO₃ + BaCl₂ → 2 AgCl + Ba(NO₃)₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

AgNO₃: 2 moles ×169.87 g/mole= 339.74 grams

BaCl₂: 1 mole ×208.24 g/mole= 208.24 grams

AgCl: 2 moles ×143.32 g/mole= 286.64 grams

Ba(NO₃)₂: 1 mole×261.34 g/mole= 261.34 grams

The following rule of three can be applied:  if by reaction stoichiometry 208.24 grams of barium chloride form 286.64 grams of silver(I) chloride, 675.9 grams of barium chloride form how much mass of silver(I) chloride?

[tex]mass of silver(I) chloride=\frac{675.9 grams of barium chloride x286.64 grams of silver(I) chloride }{208.24 grams of barium chloride}[/tex]

mass of silver(I) chloride= 930.37 grams

Finally, the mass of silver(I) chloride formed is 930.37 grams.

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The buildup of sediment in which a river empties right into a slow-transferring or non transferring frame of water is referred to as a Delta.

Deltas are wetlands that shape as rivers empty their water and sediment into some other frame of water, together with an ocean, lake, or some other river.

A form of soil made nearly completely of windblown sediment is referred to as Loess.

The natural count number in soil comes from decaying flora and animals and their waste products.

Clay, that's made of tiny debris and drains water very poorly, is one of the essential additives of soil.

A form of soil referred to as peat is maximum probably to shape in a/an Coastal surroundings in Tropical placing.

Water enables withinside the improvement of soil with the aid of using carrying Mineral and vitamins from higher layers to decrease layers.

The Richness of nutrients from soil is not unusualplace in moist environments, like rain forests.

Quartz-wealthy determine cloth results in the improvement of Sandy soils.

The layers of soil composed specifically of natural count number are referred to as the O and A horizon.

A layer of soil wherein clay, iron, and different factors from the overlying soil accumulates is referred to as the B horizon, or subsoil.

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Explanation:

it applies to pressure laws

Answer:

element.....

it is in the periodic table

Answer:

B

Explanation:

A meter stick measures distances ( like centimeters)   so....B  

  it does NOT measure mass , volume or VERY large distances (Like earth's diameter)

The quantity could best be measured with a meter stick will be "the width of a wooden block".

The measurement tool is known as a "meter stick" would be used to measure objects in meters and millimeters.

A single new piece of wood would be used to create a miniature slit drum known as a wood block.

An instrument for measuring lengths in meters and centimeters is a meter stick, which measures one meter (hundred centimeters). A meter stick can be used to measure things such as the width of a bag or the length of a table.

The quantity that could best be measured with a meter stick will be "the width of a wooden block".

Therefore, the correct answer will be an option (b)

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Q=mcΔt

Q=142.5 x 4.18 x 8

Q = 4.765 x 10³ J

Answer:

Sickle cell anemia

Explanation:

is an inherited genetic abnormality of hemoglobin (the oxygen-carrying protein found in red blood cells) characterized by sickle (crescent)-shaped red blood cells and chronic anemia caused by excessive destruction of the abnormal red blood cells.

Answer:

Sickle cell

Explanation:

I just took the test and it was correct.

2 moles of ZnO are produced if 1 mole of Zn and 2 moles of [tex]O_2[/tex] is required.

A mole is defined as 6.02214076 × [tex]10^{23}[/tex] of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.

Balanced equation:

[tex]2 Zn + O_2[/tex] → [tex]2 ZnO[/tex]

For 2 moles of Zinc, we need 1 mol of Oxygen to produce 2 moles of Zinc oxide

For 1 mole Zn, we need 2 mol [tex]O_2[/tex] to produce 2 moles ZnO only.

Hence, 2 moles ZnO is produced.

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Answer:

1.05 mols of O2 gas

Explanation:

For this type of problem, it's important to understand what the balanced Chemical equation tells us:

Let's look at the balanced chemical equation:

[tex]2Mg(s)+O_2(g)-- > 2MgO(s)[/tex]

This equation two sides of the reaction arrow.  On the left are the reactants (things you start with, and that react during the chemical reaction), and on the right side are products (things that are produced during the chemical reaction that you end with).

The numbers in front of each compound tell how many of molecules are involved for a full reaction without anything left over.  A "mol" is a large quantity ([tex]6.022*10^{23}[/tex]), in this case, of molecules , since it's unlikely you're only taking a single molecule of each substance (it would be so tiny, you wouldn't even know you were doing the reaction).

So,for every 2 moles of Magnesium used, we'll also need 1 mole of Oxygen, and it will produce 2 moles of Magnesium Oxide.

In a way, during the reaction it's almost like 2 moles of Magnesium is equal to 1 mole of Oxygen and is equal to 2 moles of Magnesium Oxide:

[tex]2 mol Mg(s)=1mol O_2(g)=2molMgO(s)[/tex]

From here, we can build some unit ratios, to convert between the known quantity of moles we have, and find the unknown quantity of moles that are requested.

We know that we are looking at 2.10 mol of Magnesium, so we want a unit ratio with moles of Mg on the bottom.  We want to find moles of O2, so we want a unit ratio of moles of O2 on top.

The unit ratio we want is the middle part of the equation, divided by the left part of the equation.

[tex]2 mol Mg(s)=1mol O_2(g)\\\frac{2 mol Mg(s)}{2 mol Mg(s)}=\frac{1mol O_2(g)}{2 mol Mg(s)}\\1=\frac{1mol O_2(g)}{2 mol Mg(s)}[/tex]

Since this quantity is 1, it is a unit ratio and can be multiplied to other things to change their units (for this problem).

Starting with what we know, and multiplying by our unit ratio:

[tex]2.10 mol Mg(s)*\frac{1mol O_2(g)}{2 mol Mg(s)}=1.05mol O_2(g)[/tex]

Notice that the units from the first quantity cancel with the units on the bottom of the fraction, leaving only the unit on top of the fraction ... the exact units we wanted!

So, 1.05mols of O2 would be consumed during the reaction if exactly 2.10moles of Magnesium are burned.

The (w/v)% concentration of vinegar contains 5g of acetic in 100mL of solution is approx 0.5 %

The concentration of a chemical substance expresses the amount of a substance present in a mixture.

There are many different ways to express concentration.(w/v)% is one of them.

Given ;

We need to convert the grams of acetic acid to moles ;

Formula of acetic acid is CH₃COOH

Thus,

Molar mass of acetic acid = 2(12.01) + 4(1.01) + 2(16)  

                                           = 24.02 + 4.04 + 32

                                           = 60.06 grams per mol

Moles of acetic acid = 5.0/60.06

                                 = 0.083 moles

(w/v)% = 0.083 x 60 / 1000 x 100

          = 0.498 %

          = 0.5 %

Hence, The (w/v)% concentration of vinegar contains 5g of acetic in 100mL of solution is approx 0.5 %

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The materials that would float in a molten vat of lead are glass and charcoal.

Glass and charcoal are the materials that would float in a molten vat of lead because they are less denser than the lead solution while on the other hand, platinum and gold get drowned into the solution because of its high density as compared to lead.

So we can conclude that the materials that would float in a molten vat of lead are glass and charcoal.

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Answer: A. Wearing loose comfortable clothing so you can concentrate on the lab.

Explanation:

Wearing loose clothing can make it cling onto certain things, which could create a spill or a different hazard. B, C, and D are all things you SHOULD be doing to achieve safe lab behavior.

I hope this helps! Pls give brainliest!! :)

Answer:

Boron, Hydrogen, Helium, Lithium, Beryllium, Carbon, Nitrogen, Oxygen, etc.

Explanation:

These are all elements, not all of them.

The data shown in the Sample of Elements table can be arranged on basis of physical and chemical properties , atomic number , atomic weight , etc .

The data shown in the Sample of Elements table can be arranged in various ways :

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Answer:

An open system is :-

B. A system that allows energy and mass to move in and out of it.

Example :-

Water boiling in a pot on a stove. (Without lid).

The types of bonds and atoms in the molecule shown below are C. Single bonds, double bonds, carbon atoms, and hydrogen atoms.

Carbon can only form a bond with a maximum of 4 other molecules.

We have been given a molecule

H₂C               CH₂-CH3

       C=C

H                H

In the given figure we can see that the molecule includes one double bond and other are single bonds.

Thus, The types of bonds and atoms in the molecule shown below are C. Single bonds, double bonds, carbon atoms, and hydrogen atoms.

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Answer:

1.57

Explanation:

moles = mass / molar mass

moles = 69 / 44.013

moles = 1.57

moles N₂O = 69 : 44 g/mol = 1.568

N₂O : 2 moles N, 1 mole O

moles N = 1.568 x 2 = 3.136

Option (b) is correct.

​​​

          A separation technique called filtration is used to isolate pure chemicals from mixtures of particles, some of which are big enough to be caught by a porous medium.

         The separation of combinations of two or more pure liquids is accomplished through distillation. The components of a liquid mixture are vaporized, then condensed and isolated during the purifying process of distillation.

          Chromatography is the process of separating a mixture by passing it through a medium where the components move at various speeds, either in solution, suspension, or as a vapor (as in gas chromatography).

         The magnetic separation process involves attracting magnetic materials using a magnet to separate the components of mixes. Non-magnetic compounds are separated from magnetic ones using the magnetic separation technique.

From the above separation techniques, we can say that option(b) Distillation a separation process that uses boiling points to separate the component of a mixture is correct.

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Answer:

last choice

Explanation:

Specific heat of a metal is    j/kg-c

It says nothing about melting point or heat of fusion

A = twice B   =  2 * j/kg-c       B = j/kg-c

 if   j is constant and mass is the same we can write this more like

    A = 2 /C       and    B = 1/C

  or    A ~  C/2      and   B~  C

now you can see that the temp change in A   will be 1/2   that of B

Answer:

12.42 g

Explanation:

because I saw your laptop so it is

Different atoms and elementary particles have varied masses. Therefore, 12.42 g is the Mass of the Water.

A body's mass is an inherent quality. Before the invention of the atom or particle physics, it was widely considered to be tied to the amount of matter inside a physical body. It was discovered that, despite having the same quantity of matter in theory, different atoms and elementary particles have varied masses.

There are various conceptions of mass in contemporary physics that are theoretically different but physically equivalent. The resistance of the body to acceleration in the presence of a net force can be measured experimentally as mass. 12.42 g is the Mass of the Water.

Therefore, 12.42 g is the Mass of the Water.

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Answer:31,631.04

Explanation: multiply final temp with initial temp = 42 then multiplied by grams = 7,560 then multiplied by J = 31,631.04

Answer:

I think D is the answer. The others can't be answer. Specially B and D can't be the answer.

Answer:

cysteine is HOOC-CH--CH₂-SH

reaction with Naoh

HOOC-CH--CH₂-SH + Naoh ---->oh-oNH2-oh + H2o

To ensure data traceability and accessibility is to complete a study beginning-to-end on a closed system or platform.

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