Which of the following is evidence that a chemical
change is occurring?

a. Cherry drink mix is added to water and the resulting
solution is red.

b. A white powder is added to cool tap water in a beaker
and the beaker gets hot.

c. Water is added to coffee until the solution becomes
clear.

d. Water is added to sand and the sand looks darker

Answer:

Na

Explanation:

Answer:

1.25M

Explanation:

Answer:

109988 grams per second

Explanation:

To solve this problem first we convert 9503 metric tons into grams, keeping in mind that:

Meaning that:

Then we calculate how many seconds are there in one day:

Finally we calculate the consumption rate:

28 mol CaF

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Stoichiometry

Step 1: Define

[Given] 1.7 × 10²⁵ molecules CaF

[Solve] moles CaF

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 2 sig figs.

28.2298 mol CaF ≈ 28 mol CaF

Answer:

A log burning to ashes is a chemical change.

Explanation:

Answer:

Chemical Change

Explanation:

Burning of wood is a chemical change as new substances which cannot be changed back [e.g. carbon dioxide] are formed. For example, if wood is burned in a fireplace, there is not wood anymore but ash.

Answer:

See explanation below

Explanation:

Let's answer this by parts.

a) As the reaction is naturally exothermic (Exerts heat), increasing temperature means that the reaction will move forward the direction where its absorbing heat

, so the equilibrium will be favored to the reactant side.

b) In this case, the addition of CO, which is a reactant will favor the reaction to the product side. This is because putting more quantity in the reactants will cause that the equilibrium constant K, increase it's innitial value, and this favors the product side.

c) In this case, it happens something similar to case b. This will cause that the reaction will have to work to cover the loss of methanol, therefore, equilibrium will move to the product side too.

d) In this case, we are adding another substance that reacts with CO, so it means that the other reactant is being removed, therefore, the reaction will work to cover this loss but also to cover the adding of the new substance, causing that the K decrease it's value, so equilibrium will be favored to the reactants side.

Hope this helps

Answer:

3 Ni + Fe(NO₃)₃ --> 3 Ni(NO₃) + Fe

Explanation:

In this question, the reactants are;

Solid Nickel and Iron nitrate. This is represented as;

Ni and Fe(NO3)3

The equation of the reaction is given as;

3 Ni + Fe(NO₃)₃ --> 3 Ni(NO₃) + Fe

The option that closely matches this is;

Option D. (Although the reaction is not balanced)

Answer:

If all the objects are placed at the same angle.

Explanation:

If all the objects are placed at the same angle so all the light from the flashlight shine comes back to the flashlight. If the A object is placed at the specific location at which the mirror X reflects the light after hitting it, then the other E object is placed at the location where the light comes after reflecting the A object then the light comes back to the flashlight if the angle between objects placement is right.

Answer:

d

Explanation:

Answer:

b

Explanation:

it could also be a, c, or d

Answer:

No, you can not calculate the solubility of X in water at 17 0C.

Explanation:

Solubility refers to the amount of a substance that dissolves in 1000 L of water.

To calculate the solubility of a solute in water, all the water is evaporated and the solid is carefully collected, washed, dried and weighed. The mass of solid obtained can now be used to calculate the solubility of the solute in water as long as there was no loss in mass of solid during the experiment.

In this case, the student threw away part of the solid that precipitated. As a result of this, the mass of solid obtained at the end of the experiment is not exactly the total mass of solute that dissolved in the solvent. Hence, the solubility of X in water at 17 0C can not be accurately calculated.

question 1 water question 2 instant tea question 3 mixture

Answer:

Plastic is better because it doesn't melt in the microwave but aluminum burns in the microwave

Explanation:

Answer:

93 kPa

Explanation:

Step 1: Given data

Step 2: Calculate the final pressure of carbon dioxide gas

If we assume carbon dioxide behaves as an ideal gas, we can calculate the final pressure of carbon dioxide gas using Boyle's law.

P₁ × V₁ = P₂ × V₂

P₂ = P₁ × V₁/V₂

P₂ = 155 kPa × 3.0 L/5.0 L = 93 kPa

Answer:

Hello the table required is missing attached below is the missing table

Answer : 1299.05 k

Explanation:

Given data :

concentration of carbon ( Cx ) at a position 3.9mm below surface = 0.35

concentration of carbon ( Co ) = 0.20

surface carbon ( Cs ) = 1

Determine the temperature at which the treatment was carried out

first we will determine the value of Z in the table attached

given that the value of erf ( Z ) for Z = 0.8125 from the table

= [tex]\frac{Z- 0.9}{0.95-0.9} = \frac{0.8125-0.797}{0.8209-0.797}[/tex]

 make Z subject of the equation

Z = 0.932

next calculate the diffusion coefficient using the relation below

Z = [tex]\frac{x}{2\sqrt{Dt} }[/tex]   ----- ( 1 )  where ; z = 0.932 , x = 3.9 mm , t = 48h

0.932 =

x = 3.9 mm = 0.0039 m

t = 48 h = ( 48 *60* 60 ) = 172800 secs

Insert values into equation 2

0.932 = [tex]\frac{0.0039}{2\sqrt{D * 172800} }[/tex]  

[tex]\sqrt{D*172800}[/tex] = (0.0039 / 0.932 ) / 2

      172800 * D  =( 0.0021 )^2

therefore D = 2.55 * 10^-11 m^2/s

Finally calculate the temperature at which the treatment was carried out

D = [tex]Do exp(\frac{-Qd}{RT} )[/tex]  ----- ( 3 )

D = 2.55 * 10^-11 m^2/s ,

Do = 2.3*10^-5  m^2/s ( gotten from Diffusion data table )

Qd = 148000 J/mol ( gotten from Diffusion data table )

R = 8.31 J/mol k ( gotten from Diffusion data table )

back to equation 3

D / Do = exp ( -17810 / T )

1.11 * 10^-6 = exp ( -17810 / T )

therefore T =  -17810 / ln( 1.11 * 10^-6 )

                   = - 17810 / -13.71  =   1299.05 k

Answer:

The percent dissociation would increase

Explanation:

Percent dissociation is the ratio of amount dissociated to the initial concentration.

Decreasing the concentration of the solution leads to an increase in percent dissociation.

Answer:

Magnesium chloride/Molar mass

95.211 g/mol

Explanation:

Explanation:

The reaction is given as;

Br2(g) + Cl2(g) ----> 2BrCl(g)

From the equation;

1 mol of Br2 reacts with 1 mol of Cl2

Converting the masses given to moles, using the formular;

Number of moles = Mass / Molar mass

Br2;

Number of moles = 33.7 g / 159.808 g/mol = 0.21088 mol

Cl2;

Number of moles = 13.0 g / 70.906 g/mol = 0.18334 mol

From the values;

0.18334 mol of Cl2 would react with 0.18334 mol of Br2 with an excess of 0.02754 mol of Br2

What is the maximum amount of bromine monochloride that can be formed? __________grams

1 mol of Cl2 produces 2 mol of Bromine Monochloride

0.18334 mol of Cl2 would produce x

Solving for x;

x = 0.18334 * 2 = 0.36668 mol

Converting to mass;

Mass = Number of moles * Molar mass = 0.36668 mol * 115.357 g/mol

Mass = 42.299 g

What is the FORMULA for the limiting reagent?

The limiting reagent is Cl2 as it determines the amount of product formed. The moment the reaction uses up Cl2, the reaction stops.

What amount of the excess reagent remains after the reaction is complete? __________grams

The excess reagent is Br2

The number of moles left is;

0.02754 mol of Br2

Converting to mass;

Mass = Number of moles * Molar mass = 0.02754 mol  * 159.808 g/mol

Mass = 4.401 g

Answer:

[tex]n=1.732mol[/tex]

[tex]\% N=18.7\%[/tex]

Explanation:

Hello!

In this case, since the molecular formula of glycine is C₂H₅NO₂, we realize that the molar mass is 75.07 g/mol; thus, the moles in 130.0 g of glycine are:

[tex]n=130.0g*\frac{1mol}{75.07 g}\\\\ n=1.732mol[/tex]

Furthermore, we can notice 75.07 grams of glycine contains 14.01 grams of nitrogen; thus, the percent nitrogen turns out:

[tex]\% N=\frac{14.01}{75.07}*100\% \\\\\% N=18.7\%[/tex]

Best regards!

Answer:

(4) concentrated and supersaturated

Explanation:

At 50.°C, 90g of KNO3 lies above the solubility curve [on the Regents Reference Table G]. This indicates that the solution is supersaturated, meaning it contains more solute than will naturally dissolve, and was formed when a saturated solution cooled. Furthermore, the percent concentration of this solution is 90% KNO3 making this solution concentrated. This can be calculated using the formula for mass percent concentration.

Percent Mass = Mass of Solute (g) x 100

                         Mass of Solution (g)

Given solution is considered as concentrated and supersaturated.

Supersaturated solutions are those solutions in which no. of dissolved solute is more and added to the saturated solution of that solute.

In the question given that,

Weight of solute or KNO₃ = 90 g

Weight of solvent or water = 100 g

Temperature = 50°C

According to the solubility curve, given solution is supersaturated because it contains excess amount of solute and it is concentrated because solute in dissolve in the saturated solution at nearly high temperature and after cooling we get the consistent solution.

Hence, option (4) is correct i.e. given solution is concentrated and supersaturated.

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Answer:

a

Explanation:

sugar is composed of different elements combined in a manner form

Answer:

The answer is option D

Explanation:

This is because Mrs. Linde resolves the conflict by committing to a new life with Krogstad, which develops the theme that new beginnings are always possible.

The conflict in this passage develops a theme, as Mrs. Linde resolves the conflict by committing to a new life with Krogstad, which develops the theme that new beginnings are always possible. Option D.

A conflict is defined as a battle or disagreement. A dispute over parenting techniques is an example of conflict, the two parties not seeing eye to eye.

In conclusion, The passages conflict develops the theme that new beginnings are always possible.

Read more about Humans

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Answer:

?????

Explanation:

...? what...?

Answer:

BaCl₂·(H₂O)₂

Explanation:

The reaction that takes place is:

The information given by the problem tells us that 5.00 g of reactant were consumed. Of those 5.00 g, 4.26 g were converted into BaCl₂, this means that the other 0.74 g were converted into water.

We convert 0.74 g of water into moles, using its molar mass:

Then we convert 4.26 g of BaCl₂ into moles:

We can write these results as (BaCl₂)₀.₀₂·(H₂O)₀.₀₄. We multiply those coefficients by 50 in order to make them integers, and we're left with:

Answer:

snow is made up of a variety of mostly organic matter, including dead or dying animals and phytoplankton, protists, fecal matter, sand, and other inorganic dust.

Explanation:

I hope I helped!!

Plz mark me brainliest it would really make my day!

Answer:

I think its organic unless we are talking about this snow storm then no

The element sulfur (S) is most likely to form covalent bonds with the element oxygen. Thus, the correct option for this question is D.

Covalent bonds may be defined as a type of chemical bond that significantly involves the mutual sharing of electrons in order to form electron pairs between atoms. This pairing of electrons is simultaneously attracted by the two atomic nuclei.

Sulfur is categorized into the category of nonmetal in group 6A, and therefore it has 6 valence electrons. In order to obey the octet rule, it needs to gain 2 electrons. It can do this by forming 2 single covalent bonds.

The sulfur atom subsequently shares four valence electrons with two oxygen atoms as two covalent double bonds, and shares its remaining two electrons with two oxygen atoms, forming two covalent single bonds.

Therefore, the element sulfur (S) is most likely to form covalent bonds with the element oxygen. Thus, the correct option for this question is D.

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Answer:

4 is the answer

Explanation:

i am not sure for this question

Answer:

I would say C) Survive

An organism will survive, move or die if there is a change to its ecosystem. Therefore, option (D) is correct.

An ecosystem contains all the organisms and the physical environment with which they interact.  The biotic and abiotic components are connected together through energy flows and nutrient cycles. Energy injects into the system through photosynthesis into plant tissue.

Animals play an important role by feeding the plants in the movement of matter and energy through the system.  Decomposers release carbon back into the atmosphere and facilitate nutrient cycling by breaking down dead organic matter.

External and internal factors control the ecosystem. External factors such as climate control the overall structure of an ecosystem but are not influenced by the ecosystem. Internal factors are controlled such as decomposition, shading, root competition, disturbance, succession, and the types of species present.

The change in the ecosystem makes the organism to adapt the environment in order to survive, move to a new place or die.

Learn more about the ecosystem, here:

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Answer:

Copper, Water, and Oxygen

Explanation:

Because they are compounds and compounds are pure substances <3

Answer: copper

Explanation: because all of the atoms that make up copper are copper i.e its not a compound or mixture. not made od molecules