Which of the following is a chemical change? A. soil drying as water evaporates B. a rock eroding as the wind removes particles from it C. a solution of salt water being diluted as water is added to it D. silver tarnishing as the silver metal reacts with sulfur

Answers

Answer 1

Answer:

Its D

Explanation:

I took the quiz

Answer 2

Answer:

D

Explanation:

IT IS REACTING


Related Questions

In frequency modulation, which wave property remains constant?

Answers

Answer:

The correct answer is - Amplitude.

Explanation:

Frequency modulation is a method or procedure that sends or transmits the signals such as radio broadcasting, telecommunication where the value of the transmitted signal is provided by the frequency of a high-frequency wave that carries the signal.

In this method of encoding the information, the amplitude of the carrier remains the same or constant but frequency varies in accordance with the modulating signal.

Answer:

The answer is C Amplitude

Explanation:

Because you can give me Brainiest  PLZZZZZZZZZZZZZZZZZZZZ

What is the work function of gold metal in kJ/mol if light with λ = 234 nm is necessary to eject electrons?

Answers

Answer

512kj/mole

Explanation:

What is the work function of gold metal in kJ/mol if light with λ = 234 nm is necessary to eject electrons?

The energy can be calculated using below expresion;

E = hc/λ

Where h= planks constant= 6.626 x 10^-34

c= speed of light= 3 x 10^

λ= wavelength

hc= (6.626 x 10^-34 x 3 x 10^ 8)

=

1. Change the following into correct scientific notation.
a) 0.03050 =
b) 0.256 x 10°=
c) 25.005 10 =​

Answers

Answer:

a) 0.03050 = 3.050 × 10-²

b) 0.256 x 10°= 2.56 × 10-¹

c) 25.005 10 =​ 2.500510 × 10¹

Explanation:

Scientific notations is a way of making very large or very small numbers more comprehensive or simplified. It involves the use of power of ten (10^). The numbers are represented to the power of ten. The following format is used:

a x 10^b

where; a is a number or decimal number between 1 and 10 i.e less than 10 but greater than 1

b is the power of ten

To write a number in scientific notation,

- we move the decimal point right or left depending on whether we're trying to reduce or increase the number

- we count the number of times the decimal point was moved. This serves as the b in the format above.

For example,

a) 0.03050 = 3.050 × 10-²

The decimal point was moved rightward twice. This caused the ^-2 power.

b) 0.256 x 10°= 2.56 × 10-¹

The decimal point was moved rightward once. This caused the ^-1 power.

c) 25.005 10 =​ 2.500510 × 10¹

The decimal point was moved leftward once. This caused the ^1 power.

How many milliliters of an aqueous solution of 0.157 M magnesium nitrate is needed to obtain 17.4 grams of the salt?

Answers

Answer:

747mL of the 0.157mL are needed

Explanation:

To find the grams of salt we need to convert these grams to moles using molar mass of magnesium nitrate (148.3g/mol). Then, with the molar concentration we can convert the moles to liters and, as last, to milliliters, as follows:

Moles Mg(NO₃)₂:

17.4g * (1mol / 148.3g) = 0.117 moles of magnesium nitrate

Volume:

0.117 moles * (1L / 0.157moles) = 0.747L

= 747mL of the 0.157mL are needed

In a 0.157M solution there are 0.157 moles per liter of solution


How many more electrons are there in the last energy level of phosphorus, atomic
number 15, than there are in the last principal energy level of neon, atomic number 10?​

Answers

sorry but I need some three point so that's why I didn't

Dr. Simmons wants to make sure her scientific investigation is considered good. She knows that for an experiment to produce valid results, it must adhere to accepted methods. Which procedure would she not include as part of her valid scientific experiment?
a) organized procedures
b) controlled surroundings
c)precise observations
d) uncontrolled variables ​

Answers

The procedure that Dr. Simmons will not include as part of her scientific experiment is uncontrolled variables.

When a scientific investigation is carried out, experiments are used as a method of verifying results. Generally, when an experiment is carried out, you want to verify that given circumstances generate a specific result.

The experiments must be as controlled as possible so that they can be repeated and thus create reliable laws. Therefore, Dr. Simmons will not include uncontrolled variables in her experiment, because these variables can modify the result of an investigation in many ways and limit the production of new knowledge.

Uncontrolled variables are generally not included in scientific investigations because they cannot be modified and they influence various results that cannot be considered reliable knowledge.

Learn more in: https://brainly.com/question/3109450

Which statement describes how phase changes
can be diagrammed as a substance is heated?
A. The phase is on the y-axis and thels
temperature is on the x-axis.
B. The temperature is on the y-axis and the
phase is on the x-axis.
C. The time is on the y-axis and the temperature
is on the x-axis.
D. The temperature is on the y-axis and the time
is on the x-axis.

Answers

B should be the answer

Answer: d

Explanation:

On edg

Each of the two different solids A and B melts at 133 o C. A sample of an unknown solid melts around 133 o C, and is either A or B. How will you determine the identity of the unknown solid

Answers

Answer:

See explanation

Explanation:

The melting point range of a pure compound is about 1-2ºC of the expected melting point. An impure solid melts within a range   that is both larger than that of the pure substance  (>1ºC) and begin at a  lower temperature because impurities decrease the meting point. A melting range of 5º or more  indicates that a compound is impure.

Since the melting points of A and B are estimated  at 133 o C, the melting point range for each pure substance must be slightly different from each other. The melting point of the unknown is measured and its range is compared with the melting point ranges of pure A and B then decision can  now be made about the identity of the unknown solid.

Select the best answer from the choice below. When the wavelength decreases, the frequency:

Answers

Answer:

Increases

Explanation:

Frequency and wavelength of lights are inversely proportional to each other.

The wave of light having highest frequency have shortest wavelength and the light with the shortest frequency having highest wavelength.

Formula:

Speed of light = wavelength × frequency

c = λ × f

λ = c/f

This formula shows that both are inversely related to each other.

The speed of light is 3×10⁸ m/s

Frequency is taken in Hz.

It is the number of oscillations, wave of light make in one second.

Wavelength is designated as "λ" and it is the measured in meter. It is the distance between the two crust of two trough.

What happens when this match is struck against the side of the match box?

Answers

Answer:

It lights on fire

Explanation:

The friction sparks the match causing it to go on fire.

Calculate the pH of a buffer solution when 32.0 mL of a 0.25 M H2CO3 is mixed with 20.0 mL of a 0.15 M NaHCO3​

Answers

pH of buffer solution : 4.32

Further explanation

A buffer solution is a solution that can maintain a good pH value due to the addition of a little acid or a little base or dilution.

The buffer solution can be acidic or basic

Acid buffer solutions consist of weak acids(H₂CO₃) and their salts.(NaHCO₃)

mol H₂CO₃

[tex]\tt 0.032\times 0.25=0.008[/tex]

mol NaHCO₃

[tex]\tt 0.02\times 0.15=0.003[/tex]

[tex]\tt [H^+]=Ka\dfrac{mole~weak~acid}{mole~salt}\\\\(H^+]=1.8\times 10^{-5}\dfrac{0.008}{0.003}=4.8\times 10^{-5}\\\\pH=5-log~4.8=4.32[/tex]

Potassium hydroxide has the chemical formula KOH. It feels slippery and is used in cleaning liquids. Based on this description, potassium hydroxide is most likely a(n) A acid. B base. с neutral solution. D pH indicator.​

Answers

Answer:

it should be a base

Explanation:

this is because solutions such as bleach are usually slippery on the hands, and mostly bases are in cleaning solutions

i really need help with the rest of this assignment. theres 10 pages of multiple choice questions, i can mark brainliest and pay money if you help me :)

Answers

Answer:

Hey! I'll help you.

Explanation:

I got your back.

A weather balloon with a volume of 3.40774 L

is released from Earth’s surface at sea level.

What volume will the balloon occupy at an

altitude of 20.0 km, where the air pressure is

10 kPa?

Answer in units of L.

Answers

Answer: The volume at an altitude of 20.0 km is 34.5289 L

Explanation:

Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.

[tex]P\propto \frac{1}{V}[/tex]     (At constant temperature and number of moles)

[tex]P_1V_1=P_2V_2[/tex]

where,

[tex]P_1[/tex] = initial pressure of gas = 101.325 kPa ( at sea level)

[tex]P_2[/tex] = final pressure of gas = 10 kPa

[tex]V_1[/tex] = initial volume of gas = 3.40774 L

[tex]V_2[/tex] = final volume of gas = ?

Now put all the given values in the above equation, we get the final volume of gas.

[tex]101.325\times 3.40774=10\times V_2[/tex]

[tex]V_2=34.5289L[/tex]

Thus the volume at an altitude of 20.0 km is 34.5289 L

Therefore, the final pressure of the gas will be 3.75 atm

What two options are homogeneous mixture

Answers

Answer:

vinegar and soap

Explanation:

Answer:

vinegar and soap

Explanation: just took the test

Which of the following has a nonpolar bond? *
02
HCI
NH3
CH4

Answers

Answer: CH4

Explanation:

BRAINLESS PLEASE

Answer:

O₂

Explanation:

The example of the compound or the molecule that forms a non-polar bond is oxygen gas.

Oxygen gas has a formula of O₂

Since this is a homonuclear molecule, the two bonding atoms have the same kind of electronegativity. The difference is therefore zero. In such a molecule, there is equal sharing of the electron pair between the atoms and no electrostatic charge on the molecule.

Which elements-O2, Rb, Sb, Pt, Y, Sm, Mn, Rh, Sn, Li-will react (a) with a solution of I to generate I2; (b) with a solution of Ag' to generate Ag; and (c) with a solution of Nat to generate Na?

Answers

Answer:

a) O2, Pt, Rh

b) Rb, Y, Sm, Mn, Sn, Li

c)Rb

Explanation:

We must consider the reduction potentials of each of the species in the question.

In (a) above, all the elements whose reduction potential is higher than the redox potential for the oxidation of I^- will react with a solution of I^- to generate I2 as shown above.

In (b) above, all the strong reducing agents can donate electrons to Ag^+ and reduce it to Ag as shown above.

In (c) Rb has a more negative reduction potential than sodium hence it can react with a solution of sodium salt to generate sodium metal.

How many electrons does Sodium lose to become an ion

Answers

For Sodium would need to lose 11 electrons to become an ion.

Other than the starting material, 2-methylcyclohexanol, what base or bases are present in the dehydration reaction mixture to participate in proton transfers?
a) H2PO4- only
b) H2O and H2PO4-
c) H2O and HSO4-
d) H2O only

Answers

Answer:

c) H2O and HSO4-

Explanation:

The dehydration of 2-methylcyclohexanol occurs in the presence of H2SO4. Recall that acids are proton donors in solution; the equilibrium shown below is then set up,

H2SO4(aq)  +  H2O(l) ⇄H3O^+(aq) + HSO4^-(aq)

The species H2O and HSO4- are two proton acceptors in the system. According to the Brownstead- Lowry definition, a base is a proton acceptor in solution.

Hence H2O and HSO4- are bases present in the dehydration of 2-methylcyclohexanol.

Chemistry of Life Practice Active 8 1 What type of organic compound is used for building cell parts?​

Answers

Carbohydrates & Lipids.

Carbs are organic compounds (examples are sugars & starches). They provide energy and form structures such as cell walls.

Lipids are organic compounds (examples are fats & oils). They store energy and help form cell membranes in addition to having other functions in organisms

Answer:

Carbohydrates

Explanation:

Using the two models, compare the processes of nuclear fusion and nuclear fission. What do the two processes have in common?
Choose all that apply.
A)
Energy is released.
B)
Elements are created
0)
A chain reaction occurs.
D)
Besides energy, neutrons are released.
E)
Both processes begin with an unstable nucleus.

Answers

Answer:it’s A and B

Explanation:

Answer:

A and B

Explanation:

They’re both fusion.

What does this image represent?
Amine group
Carbonyl group
Ether group
Hydroxyl group

Answers

I don’t really have a clear answer for you but this might help

Answer:

ether group

Explanation: I looked it up

How would you synthesize 1-hexanol starting from 1-propanol, incorporating a Grignard reagent in the synthesis?

Answers

Answer:

hjhjhjhhhhh

Explanation:

A student combines a sample of gas (2.0 L) at 3.5 atm with with another gas (1.5 L) at 2.8 atm pressure into an empty 7.0 L flask. Assuming the gases are combined at constant temperature, what is the total gas pressure (in atmospheres) in the 7.0 L flask?

Answers

Answer:

Total gas pressure is 1.60 atm

Explanation:

To solve this question we can use the Ideal Gases Law. We need to determine how many moles of each gas will be finally present at the flask of 7 L.

Let's asume the gas, are at Asbsolute T°, 273K

P. V = n . R . T

3.5 atm . 2L = n . 0.082 . 273K

(3.5 atm . 2L) / (0.082 . 273K) = 0.313 moles

(2.8 atm . 1.5L) / (0.082 . 273K) =  0.188 moles

Total moles = 0.313 mol + 0.188 mol = 0.501 mol

Let's calcualte the hole pressure

P . 7L = 0.501 moles . 0.082 . 273K

P = (0.501 moles . 0.082 . 273K) / 7L → 1.60 atm

What was the test or tests that made you decide if you compound was an aldehyde or a ketone and why?

Answers

Answer:

Tollen's test or silver mirror test is use to distinguish between ketone and aldehyde.

Explanation:

Tollen's test is use to distinguish aldehyde from ketone because Tollen reagent consist of silver nitrate and ammonia and it oxidized aldehydes to carboxylic acid and the silver Ag+ is reduced to solid silver Ag. It form a inner film wall on the tube that look like mirror. Ketone do not react with Tollen reagent and therefore does not form silver mirror on the tube wall.

Use the image to complete the sentences.

At left a grid labeled A of regularly arranged orange balls with small movement lines near each. At right a grid labeled B of regularly arranged orange balls with large movement lines near each.

Two different substances, Substance A and Substance B, are in direct contact with each other and are at different temperatures.

The particles in Substance B are vibrating
the particles in Substance A. This means Substance B is
Substance A and conduction will
.

Answers

Answer:

1. FASTER THAN- #2

2. WARMER THAN #1

3. OCCUR FROM SUBSTANCE B TO SUBSTANCE A- #3

Explanation:

I did the assignment On edg And got it right

Answer:

Use the image to complete the sentences.  

At left a grid labeled A of regularly arranged orange balls with small movement lines near each. At right a grid labeled B of regularly arranged orange balls with large movement lines near each.

Two different substances, Substance A and Substance B, are in direct contact with each other and are at different temperatures.

The particles in Substance B are vibrating

✔ faster than

the particles in Substance A. This means Substance B is

✔ warmer than

Substance A and conduction will

✔ occur from Substance B to Substance A

.

Explanation:

I know im late

Lake Michigan holds 13 billion gallons of water. If just Chicago removed water from the lake and it never rained again, how many decades would the water last?

Answers

Answer:

Check explanation section.

Explanation:

In order to be able to answer this question accurately,there is need to follow the formula below for the calculation;

Numbers of decades = total volume/ volume per decade. ----------------------(1).

So, we are given from the Question above that the volume of water in Lake Michigan = 13 billion gallons of water.

And if chicago uses 5 million gallons of water every decade.

Therefore, using the formula (1) above, we have;

Numbers of decades = 13 × 10^9/ 5 × 10^6 = 2.6 × 10^15 decades.

How would one use a Grignard-based synthesis to accomplish the following transformation? benzyl bromide (PhCH2Br) to 3-phenyl-1-propanol 1. Mg, Et20 2. ethylene oxide3. H3O+ 1. Mg, Et2O 2. Ethanol3. H3O+ 1. Mg, Et202. Ethylene 3. H3O+ None of the above.

Answers

Answer: ghfbg

Explanation: fgfghfg

Calculate the percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl on the assumption that their force constants are the same. The mass of 23Na is 22.9898mu.

Answers

Answer:

1.089%

Explanation:

From;

ν =1/2πc(k/meff)^1/2

Where;

ν = wave number

meff = reduced mass or effective mass

k = force constant

c= speed of light

Let

ν =1/2πc (k/meff)^1/2  vibrational wave number for 23Na35 Cl

ν' =1/2πc(k'/m'eff)^1/2 vibrational wave number for 23Na37 Cl

The between the two is obtained from;

ν' - ν /ν  = (k'/m'eff)^1/2 - (k/meff)^1/2 / (k/meff)^1/2

Therefore;

ν' - ν /ν = [meff/m'eff]^1/2 - 1

Substituting values, we have;

ν' - ν /ν = [(22.9898 * 34.9688/22.9898 + 34.9688) * (22.9898 + 36.9651/22.9898 * 36.9651)]^1/2  -1

ν' - ν /ν = -0.01089

percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl;

ν' - ν /ν * 100

|(-0.01089)|  × 100 = 1.089%

Answer:

1.089%

Explanation:

From;

ν =1/2πc(k/meff)^1/2

Where;

ν = wave number

meff = reduced mass or effective mass

k = force constant

c= speed of light

Let

ν =1/2πc (k/meff)^1/2  vibrational wave number for 23Na35 Cl

ν' =1/2πc(k'/m'eff)^1/2 vibrational wave number for 23Na37 Cl

The between the two is obtained from;

ν' - ν /ν  = (k'/m'eff)^1/2 - (k/meff)^1/2 / (k/meff)^1/2

Therefore;

ν' - ν /ν = [meff/m'eff]^1/2 - 1

Substituting values, we have;

ν' - ν /ν = [(22.9898 * 34.9688/22.9898 + 34.9688) * (22.9898 + 36.9651/22.9898 * 36.9651)]^1/2  -1

ν' - ν /ν = -0.01089

percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl;

ν' - ν /ν * 100

|(-0.01089)|  × 100 = 1.089%

Balance chemical equation hbr(aq)+o2(g) h20+br2

Answers

Answer:

2HBr + O2 = H20 +Br2

Explanation:

Answer:

4hbr(aq) + O2(g) = 2H2O + 2Br2

Explanation:

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