A student mixes 20.0g of white KCl crystals with distilled water in a beaker. After the mixture was stirred, no crystals are visible and the solution is clear. After several days, all of the water evaporates and white crystals are found in the beaker. Which of following pieces of experimental evidence would best help the student to confirm that a new compound had not been made and that only a physical change occurred?

Answer:

Ans => C => 43.3%

Explanation:

2CO + O₂ => 2CO₂

Given     1g CO = 1g/28g·mol⁻¹ = 0.036 mol CO

b/c coefficient of CO = coefficient of CO₂ => moles CO₂ = 0.036 mol = 0.036mol x 44g/mol = 1.57 gCO₂ (theoretical yield)

%Yield = (actual yield/theoretical yield) x 100% = (0.68g/1.57g) x 100% = 43.3%

Answer:

Here it would be A,B and C because all the examples are violating safety precautions. They are all examples of un safe signs.

Hope this helps

Explanation:

Answer:

P = momentum

m = mass

v = velocity

Answer:

P = Momentum

M = Mass

V = Velocity

Explanation:

P = Momentum  : The quantity of motion of a moving body, measured as a product of its mass and velocity.

M = Mass  : A coherent, typically large body of matter with no definite shape.

V = Velocity : The speed of something in a given direction.

Answer:

All of them have a nucleus..

Explanation:

Pretty simple stuff.  There's no cell without one.

Carlita’s body is made up of many cells. The one thing that all her cells have in common is they have the same kind of genes.

Genes are tiny pieces of spherical hereditary material that are bead-shaped and found on chromosomes. They hold the organism's genetic makeup. The number of genes on each chromosome is incalculable.

The hereditary material that makes up chromosomes is arranged in x shapes inside the nucleus. DNA, genes, and proteins make it up. An organism's genotype is distinct from other organisms because of its distinct genetic makeup, and this distinction can be passed down from one generation to the next.

Traits may be influenced by genes, the environment, or a mixture of the two. Quantitative features can also be qualitative, such as eye colour (such as height or blood pressure).

Therefore, numerous cells make up Carlita's body. Her cells all share the same type of genes, which is the only thing that unites them.

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Answer:

Question 4 is 291.0346

Explanation:

Answer:

calcium oxide

Explanation:

its stable

There are several metals which can be used to reduce the metal oxides to corresponding metals. Carbon is an efficient reducing agent. Here Calcium oxide cannot be reduced to calcium by carbon. The correct option is C.

The reaction of metals with oxygen result in the formation of oxygen containing compounds called metal oxides. The binary compounds of oxygen with lesser electronegative elements are called oxides. Most of the stable oxides have 'O' in its -2 oxidation state. Na₂O, CO₂, etc. are some oxides.

Carbon is a reducing agent and it is present above the elements like 'Zn', 'Cu', 'Fe', 'Ag', etc. in the electrochemical series. But the oxides of highly reactive metals cannot be reduced with carbon. Because these metals have more affinity for oxygen than carbon.

The highly reactive metals are extracted by using the electrolytic reduction of their molten chloride. It is not possible for carbon to reduce the oxides of metals like 'Na', 'Ca', 'Al', etc.

Thus the correct option is C.

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Answer:

The students should create a project in which they each look at a unique trait that each have (for example, detached ear lobes) and look at their parents to see if they too have this trait. To take it a step further, look at their grandparents for this trait, and ask them about their parents and if they have this trait, this could tell them whether the trait has always, been apparent within the family, if it skipped a generation, or the genetics of one parents were more dominant then the other.

Answer:

V₂ = 238.05 L

Explanation:

Given data:

Final volume = ?

Initial volume = 13.40 L

Initial pressure = 1.51 atm

Final pressure = 65 mmHg ( 65/760 = 0.085 atm)

Solution:

The given problem will be solved through the Boyle's law,

"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"

Mathematical expression:

P₁V₁ = P₂V₂

P₁ = Initial pressure

V₁ = initial volume

P₂ = final pressure

V₂ = final volume  

Now we will put the values in formula,

P₁V₁ = P₂V₂

1.51 atm × 13.40 L = 0.085 atm × V₂

V₂ = 1.51 atm × 13.40 L /  0.085 atm

V₂ = 238.05 L

Answer: Well take this for an example and see if it helps with 50 grams of sucrose

Explanation:

Explanation:

And we have to calculate the number of moles of sucrose present in a  

lb

mass of sucrose:

Moles of sucrose

=

454

⋅

g

342.30

⋅

g

⋅

m

o

l

−

1

=

1.33

⋅

m

o

l

.

Now it is a fact that in a  

mole

of stuff there are  

6.022

×

10

23

individual items of stuff.........

So  

1.33

⋅

m

o

l

×

6.022

×

10

23

⋅

m

o

l

−

1

≅

8

×

10

23

individual

sucrose molecules

Answer:

I think it's the A one. Hope it's correct

Answer:

A option is correct

Explanation:

Answer:

Stomata take in water, sunlight, and carbon dioxide and release oxygen.

Explanation:

Photosynthesis collects and absorbs sunlight and converts the sunlight into sugars (glycose), then the plant stores the sugar and uses it.

Answer:

ye

Explanation:

ye

Water boils when the vapour pressure is least the atmospheric pressure.

The atmospheric pressure is equal at the top of the mountain.

The air around you has weight, and it presses against everything it touches. That pressure is called atmospheric pressure, or air pressure. It is the force exerted on a surface by the air above it as gravity pulls it to Earth.

As we go up in altitude the air pressure becomes less. When the pressure decreases, it takes less energy to get the water molecules to escape the surface. So the temperature is less than it would be at sea level.

Air pressure is higher or greater at the bottom of a mountain. This is because the height of the air above that level is thicker than at the top.

Pressure is given by the equation, P=rho*g*h, where rho is the air density, g is the gravity value and h is the thickness of the air layer on top of the level where we are considering the pressure.

Therefore, as we can see, at the bottom of the mountain, the thickness h of air is greater, and so is the pressure.

Hence, water boils when the vapour pressure is least the atmospheric pressure and the atmospheric pressure is equal at the top of the mountain.

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Answer:

ZnO + H2SO4 = ZnSO4 + H2O | Chemical reaction and equation

Explanation:

gloogle

Answer: The steepness of a ramp affects it by making it easier or harder.

Explanation: It's a bit situational. If you were going up a steep ramp with a heavy load, it will increase the work necessary, whereas if you were going down a ramp, it would decrease the work necessary. If you need this simply put, think about biking up and down a hill. It would be easier going down than up.

Answer:

HERE

Explanation:Therefore, there will be

6.022

×

10

23

oxygen atoms in

1

mole, or

18 g

of water.

Explanation:

Carbon-12 and carbon-14 are two isotopes of the element carbon. The difference between carbon-12 and carbon-14 is the number of neutrons in each of their atoms. Atoms of both isotopes of carbon contain 6 protons. Atoms of carbon-12 have 6 neutrons, while atoms of carbon-14 contain 8 neutrons.

Answer:

A. write balanced chemical equation (including states), for this process.

Explanation:

Almost all hydrocarbon 'burn' reactions involve oxygen; it's by far the most reactive substance in air.  

Hydrocarbon combustions always involve  

[some hydrocarbon] + oxygen --> carbon dioxide + steam.  

C6H6(l) + O2 (g)--> CO2 (g)+ H2O (g)

Balance carbon, six on each side:  

C6H6(l) + O2 (g)--> 6CO2 (g)+ H2O (g)

Balance hydrogen, six on each side:  

C6H6(l) + O2 (g)--> 6CO2(g) + 3H2O (g)

Now, we have fifteen oxygens on the right and O2 on the left.  

Two ways to deal with that. We can use a fraction:  

C6H6 (l)+ (15/2)O2 (g)--> 6CO2 (g)+ 3H2O (g)

Or, if you prefer to have whole number coefficients, double everything  

to get rid of the fraction:  

2C6H6 (l)+ 15O2 (g)--> 12CO2 (g)+ 6H2O (g)

With the SATP states thrown in...  

C6H6(l) + (15/2)O2(g) --> 6CO2(g) + 3H2O(g)

Answer:

chemical structure determines the molecular geometry of ca compound by prtraying the arrangement of atoms and chemical bonds in the molecule..

Explanation:

hope this helps any <3

Answer:

x is horizontal

y is vertical

Explanation:

The properties most likely belong to a metal are ductile and malleable.

Malleability - Those metals that can be beaten into thin sheets with a hammer or any heavy object. For example - Cu, Au etc

Ductility- The property of the metals which can lead the metals to form them into wires.

Conductivity - Conductivity is the measure of the ease at which an electric charge or heat can pass through a material. For example - Metals are good conductors of heat and electrolytic solution is conductors of electricity.

Metals have many other properties including the given above, like sonority,  lustrous surface, very hard etc.

Therefore, The properties most likely belong to a metal are ductile and malleable.

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Answer:

Similarity: Rocks within the mantle contain more magnesium and iron than the ones in the crust.

Difference: Rocks in the deep mantle are under intense heat and pressure. In this case, they are semi-solid rocks that flow slowly. On the other hand, the part of the mantle that is nearest to the surface consists of rigid rocks. It has a lower temperature than the rocks in the deep mantle.

Explanation:

Rocks within the mantle contain more magnesium and iron than the ones in the crust.

Rocks in the deep mantle are under intense heat and pressure. In this case, they are semi-solid rocks that flow slowly.

On the other hand, the part of the mantle that is nearest to the surface consists of rigid rocks. It has a lower temperature than the rocks in the deep mantle.

According to geologists, a rock is a naturally occurring material made up of crystalline crystals of various minerals that have fused together to form a solid mass.

Therefore, Rocks within the mantle contain more magnesium and iron than the ones in the crust.

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Answer:

Nitrogen has an atomic number of 7 (Z=7) because it has 7 protons in its nucleus. Some nitrogen atoms have an atomic mass number of 15 (A=15). A is the number of neutrons plus protons in the nucleus. However, we already know that there are 7 protons

Answer:

Atomic number = Number of protons = Number of electrons

Atomic number = 7

Given that,

The equation is : [tex]6CO_2+6H_2O+\text{sunlight}\rightarrow C_6H_{12}O_6+?O_2[/tex]

To find,

The missing coefficients.

Solution,

[tex]6CO_2+6H_2O+\text{sunlight}\rightarrow C_6H_{12}O_6+?O_2[/tex]

Let the value of ? is x.

It is the equation of photosynthesis.

In LHS,

Carbon atoms = 6

Hydrogen atom = 12

Oxygen atom = 18

In RHS,

Carbon atoms = 6

Hydrogen atom = 12

Oxygen atom = 6

If we make the equation as [tex]6CO_2+6H_2O+\text{sunlight}\rightarrow C_6H_{12}O_6+6O_2[/tex]

No the number of atoms in RHS = 6+ 12 = 18

It means if we take the value of ? as 6 the equation will be balanced.

Hence, the correct option is (B) "6".

Answer:

170.4L

Explanation:

The reaction equation is given as:

        N₂  +   3H₂  →    2NH₃  

Mass of NH₃    =  35.5g

Problem:

How many liters of H₂ are needed to produce 35.5g of NH₃  

Solution:

To solve this problem, let us find the number of moles of NH₃;

           Number of moles  = [tex]\frac{mass}{molar mass}[/tex]

Molar mass of NH₃   = 14 + 3(1)  = 17g/mol

 So;

            Number of moles  = [tex]\frac{35.5}{17}[/tex]  = 5.07mole

From the balanced reaction equation:

               2 mole of NH₃   will be produced from 3 mole of H₂  

               5.07mole of NH₃ will produce  [tex]\frac{5.07 x 3}{2}[/tex]   = 7.61mole of H₂

At STP;

       1 mole of gas will occupy 22.4L

     7.61 mole of H₂ will occupy 7.61 x 22.4  = 170.4L