Which of the following pieces of evidence suggests there was a chemical change?
Change in color
Change in shape
Change in size
Change in state

Answers

Answer 1

Answer:

Change in colour will be the answer.


Related Questions

The volume occupied by a certain mass of methane gas (CH4)
at STP is 420 L. What will be its mass in grams at STP?
a
500 g
b 400 g
C 300 g
d None of the above

Answers

Answer: 300 g

Explanation: I guessed and got it right

420 liter of volume is occupied by 300 grams of methane gas at standard temperature and pressure (STP).

How we write the ideal gas equation at STP?

Ideal gas equation of methane gas at STP (standard temperature pressure) can be written as:

PV = nRT, where

P = pressure = 1 atm

V = volume = 420 L (given)

R = universal gas constant = 0.082 L.atm / k.mole

T = absolute temperature = 273 K

n = no. of moles to find?

Putting all these values in the above equation and calculated for the n:

n = (1 × 420) / (0.082 × 273) = 18.76 moles

Now we calculate mass of methane by the definition of moles as:

n = W/M, where

M = molar mass of methane = 16 g/mole

W = to find?

W = 18.76 × 16 = 300.2 grams or 300grams.

Hence, option (c) is correct i.e. 300 grams of methane occupy 420 L volume.

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A solution is prepared by mixing 769 mL of ethanol with 507 mL of water. The molarity of ethanol in the resulting solution is 10.8 M. The density of ethanol at this temperature is 0.7893 g/mL. Calculate the difference in volume between the total volume of water and ethanol that were mixed to prepare the solution and the actual volume of the solution.

Answers

Answer:

57 mL

Explanation:

To make things clear, when 769 mL of ethanol were mixed with 507 mL of water, the resulting volume was not (769+507) 1276 mL, but a lower value. This is because of the interactions between liquid molecules.

First we calculate how many grams of ethanol are there in 769 mL, using the given density:

mass = density * volume0.7893 g/mL * 769 mL = 606.97 g ethanol

Then we convert 606.97 g of ethanol into moles, using its molar mass:

606.97 g ÷ 46.07 g/mol = 13.17 mol

Now we calculate the actual volume of the solution, using the definition of molarity:

Volume = Moles / Molarity13.17 mol / 10.8 M = 1.219 L

Finally we convert 1.219 L to mL, and calculate the difference in volume:

1.219 L * 1000 = 1219 mL1276 mL - 1219 mL = 57 mL

What is the most likely oxidation state of nitrogen?
O A. -2
OB. +3
O C. +4
O D.-3

Answers

D is the answer -3                            m              

What is the mass of 0.0071 moles of lead?

Answers

Answer: 1.47 g

Explanation:

207.2 g/mol × 0.0071 mol = 1.47 g

You can find the molar mass of lead, Pb, on the periodic table, 207.2 g/mol.

0.0071 moles lead = 1.47112 grams

ANSWER FAST
is water wet?
a.) yes
b.) no
c.) a baby goat is a kid

Answers

Answer:

c

Explanation:

menciona tres ejemplos en los que un cálculo incorrecto en los en ingredientes indispensables para la elaboración de un producto traería consecuencias graves químicamente hablando ​

Answers

Explanation:

Cada producto o servicio, independientemente de su propósito, debe ser seguro de usar y desarrollado de acuerdo con los más altos estándares de calidad y seguridad.

Algunos ejemplos de cálculo incorrecto de ingredientes que tendrían graves consecuencias químicas podrían ser:

Medicamentos y vacunas: Este es quizás uno de los ejemplos que tendría las consecuencias más graves para las personas si hubiera un cálculo incorrecto de ingredientes, ya que la producción de medicamentos y vacunas es una industria que requiere la máxima calidad agregada debido a que se ocupa directamente de la salud y los errores de formulación pueden agravar la enfermedad y causar la muerte. Actualmente tenemos el ejemplo de la vacuna para el control de la pandemia, que antes de ser aprobada tuvo que someterse a una serie de investigaciones, pruebas en humanos y diferentes fases para demostrar su efectividad y no causar daño al organismo humano.

Cosméticos: Existen cosméticos de la industria de la belleza que tienen la función de prevenir el envejecimiento cutáneo, alisar el cabello, etc. Por tanto, un cálculo incorrecto de los ingredientes químicos también podría provocar daños irreversibles a la salud, como quemaduras en la piel, caída del cabello, alergias, cáncer, etc.

Alimentos: La industria alimentaria utiliza componentes químicos con el fin de conservar los productos y aumentar la vida útil, por lo que si se usan en cantidades mayores de las necesarias, dichos compuestos pueden causar enfermedades en las personas como intoxicación alimentaria, cáncer, gastritis, etc.

plsss helpp ASAP
BRAINLIEST

Answers

Answer:

Specific heat is defined by the amount of heat needed to raise the temperature of 1 gram of a substance 1 degree Celsius (°C). Water has a high specific heat capacity which we'll refer to as simply "heat capacity", meaning it takes more energy to increase the temperature of water compared to other substances.

Explanation:

Yes water has a specific heat capacity

What do acids do in solution?

Answers

B
The answer should be B.....

How many electron shells does a neon atom have?

Answers

2,8 that is the answer to ur question

Answer:

2 electron shells

hope it helps

and your day will be full of happiness

PLS HELP

A student takes some cold water in a beaker and dissolves two tablespoons of salt in it. When the student adds one more tablespoon of salt it gets settled at the bottom of the beaker. The student warms the water and observes that the salt disappears. What can be the reason for this observation?

Heat increases the solubility of water

Heat evaporates the excess salt in solution

After heating the solution become saturated

Two table spoon of salt makes the solution unsaturated

Answers

Answer:

A

Explanation:

If 5 times a number is increased by 4 the result is 19 find the lest possible number that satisfies theses condition

Answers

Answer: 3

Explanation: 5 times a number would be 5x, then increase that by 4 is 5x+4.  The problem then says 5x + 4 ≥ 19.  If we solve for x then we get x ≥ 3 so x has to be greater than or equal to 3, so the smallest number it could be is 3.  You can even try any number smaller than 3 and see it doesn't work.  even something like 2.9

What is the mass of 5.80 × 10²³ atoms of silver (Ag)?

A. 0.00893 g
B. 0.00963 g
C. 104 g
D. 112 g

Answers

Answer:

104 g

Explanation:

i just solved it

How many grams of molecular chlorine will be required to completely react with 0.0223 moles of sodium iodide according to the following reaction?

2Nal + Cl2 ---> 2NaCl + I2

A. 1.57 104 grams
B. 3.16 grams
C. 0.0112 grams
D. 0.791 grams​

Answers

The amount of chlorine will be 0.791 gram required to completely react with 0.0223 moles of sodium iodide .

The given chemical reaction is :

2Nal + [tex]Cl_{2}[/tex] → 2NaCl + [tex]I_{2}[/tex]

It is given that:

Amount of sodium iodide = 0.0223 mol.

Atomic mass of chlorine = 35.45 g.

The amount of chlorine can be calculated as:

0.0223mol. NaI × (1mol. Cl₂/2mol. NaI) × (35.45g/1mol. Cl2)

=0.791 grams

Therefore, the correct answer will be option (D).

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If 2.50 grams of ethane is allowed to react with 5.00 grams of oxygen how many grams of water would be expected?

Answers

Answer:

The mass of water produced is 4.29 g.

Explanation:

Given;

reacting mass of ethane, C₂H₆ = 2.5 g

reacting mass of oxygen, O₂ = 5.0 g

The balanced combustion reaction is given as follows;

2C₂H₆   +   7O₂ ---------------->  4CO₂    +   6H₂O

Based on the balanced equation above;

                                     requires

7.0 moles of oxygen ----------------------->   2.0 moles of ethane

                                   requires

5.0 g of oxygen      -------------------------->  x gram of ethane

x = (2 x 5) / 7

x = 1.43 g

Ethane is in excess of 1.07g (2.5 g - 1.43g)

Now, determine the mass of water produced by 1.43 g of ethane;

                                   requires

2.0 moles of ethane ----------------------->   6.0 moles of water

                                   requires

1.43 g of ethane      -------------------------->  y  gram of water

y = (6 x 1.43) / 2

y = 4.29 g

Therefore, the mass of water produced is 4.29 g.

hi help plz .........

Answers

Answer:The answer is C) The total mass of C and D only.

What is an Oxidizing Agent? ( answer in simple language)​

Answers

Answer:

an agent that helps accept electrons on others like oxygen, halogens

Explanation:

a substance that tends to bring about oxidation by being reduced and gaining electrons.

Please mark me as brainliest

The triple point of water occurs at a pressure of 4.59 mmHg.
What is the pressure in atm?

Answers

Answer:

The pressure in atm is 6.04 x 10^-3

Explanation:

Pressure of the gas is defined as the force exerted by the particles on the walls of the container. It is expressed in various terms like 'mmHg', 'atm', 'kiloPascals' etc..

All these units of pressure are inter convertible.

Pressure of the gas = 4.59 mm Hg

760 mm Hg = 1 atm

4.59 mm Hg= 1/760 x 4.59 = 6.04 x 10^-3atm

The pressure in atm is 6.04 x 10^-3

salat tarawih itu boleh dilakukan di masjis

periodic table
fill in the box :)

Answers

Answer:

I took a screen shot of your image, and wrote on top of it!

Explanation:

Hope this helps! :)

2. Katelyn is drinking a glass of tea. As the tea sits in the sun it begins to warm up. To
cool it back off again, she puts more ice in the glass.
After she puts ice in the glass, the ice tea cools down. What is occurring to the heat
in the glass?

Answers

AnswerB:

Explanation:

Heat can travel from one place to another in different ways. The different methods of heat transfer are conduction, convection and radiation. Here heat transfers from the glass to the ice through conduction.

What is conduction?

The process of transmission of energy from one particle of the medium to another with the particles being in direct contact with each other is defined as the conduction. It is also known as the thermal conduction or heat conduction.

In conduction an area of higher kinetic energy transfers thermal energy towards the lower kinetic energy area. Here a transfer of heat energy occurs from tea molecules to the ice cube. Due to the transfer of heat melting of ice occurs.

As the ice melts, the tea starts cooling while heating the ice cube. So the ice cools down the tea. The tea will be melted by the ice here.

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What structural formula represents 4 electrons shared between two atoms?
O 0=0
O Sg
ONEN
OP4

Answers

I’m like 98% sure it is the first one

Chemistry Challenge
Imagine someone who had never seen a city before.
They have lived their entire life alone, in a cave.
Answer
How could you get them to understand a city without
taking them there?
.
Students, write your response!
Pear Deck Interactive Slide
Do not remove this bar

Answers

Answer:

I will draw how the city looks like

True or False. Physical changes result in the formation of a new substance.

True or False. A major clue to a chemical change is the formation of a new
substance.

Answers

Answer:

1. false

2. true

Explanation:

I hope this helps

The actual brightness of a supergiant is more than the actual brightness of our sun. Explain why this
A supergiant is the largest star in space, so it is the brightest,
A supergiant is made up of different gases than our sun, so it is brighter,
A supergiant appears brighter than our sun, but our sun is actually brighter,
A supergiant is more powerful than our sun, so it gives off more light energy,

Answers

ilovemememmememekdkdmemememmemememwmwmemmwmwmwmwmememememe

AMSWER:

B. I'm sorry if this is wrong

Explanation:

what is the number of electrons in the element Nickel

Answers

28 (it’s the same as the atomic number)

Identify any incorrect formulas. Explain your answer.


a. Mg2(SO4)3


b. Rb3As


c. BeCl3


d. NaF

Wish I could award more points but I'm running low.

Answers

A is incorrect because Mg has a 2+ charge, while SO4 has a 2- charge, if there is 2 Mg and 3 SO4 then the formula will not add to 0 meaning neutral

The formula of a compound is written based on the valency of each bonded atoms. The formulas  Mg₂(SO₄)₃, Rb₃As are incorrect. Such compounds does not exist.

What is chemical formula?

The formula of a chemical compound is written based on the number of atoms participated in bonding.   Magnesium is second group element having two valence electrons.

Magnesium thus donates its two electrons into the bonding atom or group. The sulphate group SO₄ have a valency of 2 it gains two electrons from Mg when bonded.

Thus the formula of magnesium sulphate being MgSO₄ and not Mg₂(SO₄)₃. Similarly Rb is a second group metal having two valence electrons. Its valency being two. As is a halogen with valency one. Thus they cannot form a compound like Rb₃As.

Hence, option a and b are incorrect formulas.

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I NEED HELP ON THIS SCIENCE QUESTION

Answers

The answer is IRON.

Density is mass divided by volume. When you divide the mass 51.52 by the volume 7, you get the answer 7.36, which is the density of iron

11.7 g of NaCl and 4.5 g of KBr were dissolved
in 47 g of water. What is the molality of NaCl
in the solution?

Answers

Answer:

4.26m

Explanation:

Molality , m, is an unit of concentration in chemistry defined as the ratio between moles of solute (In this case, NaCl) and kg of solvent (In this case, water).

To solve the question we need to find the moles of NaCl and the mass of water in kg:

Moles NaCl -Molar mass: 58.44g/mol-:

11.7g * (1mol / 58.44g) = 0.200 moles

Mass of Water in kg:

47g * (1kg / 1000g) = 0.047kg

Molality is:

0.200 moles / 0.047kg =

4.26m

An atom of a mystery element contains 6 protons, 6 electrons, and 8 neutrons.
What is the mass number?

Answers

Answer:

14

Explanation:

Mass number is just the value of the protons and neutrons added, in this case its 14


Kevin is working on a model that shows the positions of Earth, the Moon, and the Sun during the phases of the Moon. How should he position them to show a New Moon?

Answers

A black ball is probably the best way to show it sense we can’t see a new moon when it’s around

HELPP ILL GUVE YOU LOTS OF POINTS EVERYTHING U WANT I REALLY NEED HELP ​​

Answers

Answer:

finally found

31th July 2000

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