help me please give two example in which physical change take place please help me​

Answers

Answer 1

Answer:

Boiling, melting

Explanation:

Physical changes affect the form of a chemical substance.


Related Questions

what is the valence electron for magnesium 2+​

Answers

Answer:

two valence electrons

Explanation:

Magnesium is alkaline earth metal and belongs to group IIA of the periodic table. It has two valence electrons which are present in 3s subshell.

pls Mark me as brainliest trust me

Answer:

Magnesium has two valence electrons.

Explanation:

Magnesium is element 12 and belongs to Group 2 of the Periodic Table. An element in Group 2 has two valence electrons.

Here is a video which discusses how to determine the electron configuration of magnesium.

https://youtu.be/AOxaVdA-Sv0

During an experiment, solid iodine was placed in a sealed container. The container was gradually heated and purple-colored vapors of iodine formed were observed. Describe this system when it reaches phase equilibrium.

Answers

Answer:

See explanation

Explanation:

A system is said to have attained dynamic equilibrium when the rate of forward reaction and the rate of reverse reaction are equal.

Considering the system under consideration;

I2(s)⇄I2(g)

Heating the container converts solid iodine to purple coloured iodine vapour.

At equilibrium, there will be no net change in the amount of solid iodine and iodine vapour present in the system because the two processes (forward and reverse reactions) occur at the same rate at equilibrium.

ASAP PLEASE HELP What is the wavelength of a photon with a frequency of 6.56 x 1014 Hz?
A. 197 nm
B. 457 nm
O C. 303 nm
D. 435 nm

Answers

Answer:

B. 47 nm is the wavelength of a photon with a frequency of 6.56 x 1014 Hz.

Answer:

B. 457 NM ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

                                                                                                                                         

At a temperature of -25 °C, a sample of gas in a rigid container exerts a pressure of 55.8 kPa. At what temperature will the pressure reach 145 kPa?

Answers

The required temperature of the gas sample is -64.96 °C.

What is ideal gas equation?

Ideal gas equation gives idea about the behavior of gas at different condition & represented as:

PV = nRT.

From the above equation it is clear that relation between temperature and pressure for this question is:

P₁/T₁ = P₂/T₂, where

P₁ & T₁ are the initial pressure and temperature.

P₂ & T₂ are the final pressure and temperature.

On putting values, we get

T₂ = (145)(-25) / (55.8) = -64.96 °C

Hence required temperature of the sample is -64.96 °C.

To know more about ideal gas equation, visit the below link:
https://brainly.com/question/1056445

#SPJ2

Why are most plants green out of all the colors?

Answers

Answer: Different forms of chlorophyll

Explanation:

Depending on the significance the of the chlorophyll it’s function is to absorb light, which excites electrons in the chlorophyll.

Answer:

Plant cells have an organelle called chloroplast in them. Chloroplast contains a green pigment called chlorophyll which gives plants it's green color.

Chlorophyll is important in plants as it helps the plant in producing food with the process of photosynthesis.

Which statement correctly describes a product of a reaction within
photosynthesis?
O A. ATP is produced during the light reactions.
O B. Carbon dioxide is produced during the light reactions.
O C. Oxygen is produced during the Calvin cycle.
OD. NADPH is produced during the Calvin cycle.

Answers

Answer:

B

pls correct me if im wrong

The Austrian monk and scientist Gregor
studied the traits of pea plants. He could see that pea plant traits were passed from parents to offspring in a process called
.

Answers

Answer:

Mendel, Inheritance/Heredity

Explanation:

Gregor Mendel (1822-1884) was an Austrian monk and scientist as stated in this question. He is referred to as the FATHER OF GENETICS due to his immense contributions to the principle of inheritance.

Gregor Mendel via his several works conducted on pea plants was able to demonstrate how traits passed down from parents to offsprings in a process called INHERITANCE OR HEREDITY.

Your Answer is : 1st Mendel  and 2nd heredity.

Explanation:

What are this element’s chemical and physical properties? Explain how the chemical properties affect the physical properties of an element.

Answers

Answer:

What element is this. Would you mind inserting a picture or naming the element in the comments section

What is the mass of NaCl required to make 140 grams of a 12% solution of NaCl in water?
12 grams
14 grams
17 grams
18 grams

Answers

Answer: The mass of NaCl required to make 140 grams of a 12% solution of NaCl in water is 17 g.

Explanation:

Given: Mass of solution = 140 g

Mass percent = 12%

Formula used to calculate grams of solute are as follows.

[tex]Grams of solute = \frac{grams of solution \times mass percent}{100 percent}[/tex]

Substitute the values into above formula as follows.

[tex]Grams of solute = \frac{grams of solution \times mass percent}{100 percent}\\= \frac{140 g \times 12 percent}{100 percent}\\= 16.8 g\\= 17 g[/tex]

Thus, we can conclude that the mass of NaCl required to make 140 grams of a 12% solution of NaCl in water is 17 g.

Considering the definition of percentage by mass, the correct answer is the third option: 17 grams of NaCl is required to make 140 grams of a 12% solution of NaCl in water.  

The Percentage Composition is a measure of the amount of mass that an element occupies in a compound and indicates the percentage by mass of each element that is part of a compound.

This is, the percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.

In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.

The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

[tex]percentage by mass=\frac{mass of solute}{mass of solution}x100[/tex]

In this case, you know:

percentage by mass= 12%mass of solute= ?mass of solution= 140 grams

Replacing:

[tex]12=\frac{mass of solute}{140 grams}x100[/tex]

Solving:

mass of solute= [tex]\frac{12 x 140 grams}{100}[/tex]

mass of solute= 16.8 grams ≅ 17 grams

Finally, the correct answer is the third option: 17 grams of NaCl is required to make 140 grams of a 12% solution of NaCl in water.

Learn more about percentage by mass:

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some one help please ​

Answers

oxnzle ...............

Answer: oxnzle

Explanation:

.......................

Answers

...

....................................

Explain the difference between the movement of water molecules at room temperature and at 0 'C.​

Answers

Answer:

at room temperature: -water is in liquid state bcecause of which molecules are freely moving

at 0°C:- it is freezing pointof water in this state water molecule can't move due to which there is no collision and chemical reaction will not take place

Explanation:

if i m right than tag me brilliant

The difference is in the speed of the molecules. At 0°C, the molecules move more slowly than at room temperature as their potential energy decreases.

explain about brownian movement in your own word ​

Answers

Answer:

Brownian moment means zig-Zag motion of particals Randomly anywhere in the free space or in fluids

Why does every chemical reaction require a certain amount of activation energy?

Answers

Explanation:

Activation energy is the minimum amount of energy required for a chemical reaction to take place.

When a chemical reaction occurs then bonds between the reactants break and bonds between the products are formed. This leads to the formation of an activated complex which is also known as transition state.

So, in order to form the activated complex a minimum amount of energy is necessary and this energy is known as activation energy.

Nitrogen dioxide, a major air pollutant, can be produced by the combustion of nitrogen oxide as shown. 2NO + O2 Right arrow. 2NO2 In a plant, 1,500 kg of nitrogen oxide is consumed per day to produce 1,500 kg of nitrogen dioxide per day. What is the percent yield? Use Percent yield equals StartFraction actual yield over theoretical yield EndFraction times 100.. 21.7% 32.6% 43.5% 65.2% Mark this and return Save and Exit Next Submit

Answers

Answer:

65.2%

Explanation:

It is given that :

[tex]$2NO + O_2 \rightarrow 2NO_2$[/tex]

Therefore, 60 g of nitrogen oxide will produce 92 g of nitrogen dioxide

or 60 kg of nitrogen oxide will produce 92 kg of nitrogen dioxide

or 1500 kg of nitrogen oxide will produce [tex]2300\ kg[/tex] of nitrogen dioxide

Therefore the percentage yield = (Actual yield / Expected yield) x 100

percentage yield = [tex]$\frac{1500}{2300} \times 100$[/tex]

Percentage yield = 65.217 %

Answer:

the person above me is correct, the answer for this is 65.2% or option D!

Explanation:

thank you person above me! i got a 100% on the test! :D

According to Le Châtelier's principle, how will an increase in pressure affect a gaseous equilibrium system? O Shift it toward the products O Shift it toward the reactants Shift it toward the side with higher total mole concentration O Shift it toward the side with lower total mole concentration​

Answers

Answer:

Shift it toward the side with lower total mole concentration

Explanation:

The reaction will shift in a direction that is less affected by stress, so that the pressure is reduced. This means that the reaction will change towards where there is fewer gas molecules (the fewer gas molecules, the smaller the pressure).

Answer:

A. Shift it toward the side with lower total mole concentration

Explanation:

What kind of reactions are redox reactions

Answers

A reaction in which reduction and oxidation take place simultaneously known as a redox reaction.

What is the percent yield of either if 1.11L(d=0.7134 g/mL) is isolated from the reaction of 1.500L of C2H5OH

Answers

Answer:

Percent yield of ether = 83.18%

Explanation:

Equation of the synthesis reaction of ether from ethanol is given as follows :

2 C₂H₅OH -----> C₂H₅OC₂H₅ + H₂0

Density = mass / volume

Therefore mass = density × volume

Density of ether = 0.7134 g/mL; volume of ether produced = 1.11 L = 1110 mL; Molar mass of ether = 74 g/mol

Mass of ether produced = 0.7134 g/mL × 1110 mL = 791.874 g

Density of ethanol = 0.789 g/mL; volume of ethanol = 1.50 L = 1500 mL; molar mass of ethanol = 46 g/mol

Mass of ethanol reacted = 0.789 g/mL × 1500 mL = 1183.5 g

From the equation of reaction, 2 mole of ethanol produces 1 mole of ether

Mass of 2 moles of ethanol = 2 × 46 = 92 g

Therefore, 92 g of ethanol produces 74 g of ether

1183.5 g of ethanol will produce 1183.5 × 74/92 grams of ether = 951.945 g of ether

Percent yield of ether = actual yield/theoretical yield × 100%

Actual yield of ether = 791.874 g; theoretical yield of ether = 951.945 g

Percent yield of ether = (791.874 g × 951.945 g) × 100 %

Percent yield of ether = 83.18%

need help w the questions in the pic! thankyouu

Answers

Answer: Here are the answers

Explanation:

7a) Calcium Chloride +water+carbon dioxide

b)Calcium Oxide +Carbon dioxide

8a) zinc + carbon monoxide

b) Aluminum + Carbon dioxide

c) Lead + carbon dioxide

What are the concentrations of hydronium and hydroxide ions in a solution with pH 2.6?

Answers

hey hi mate

wassup

answer is 4

explanation To calculate the pH of a solution, use the equation

p

H

=

log

[

H

3

O

+

]

Since we are given the hydronium ion (

H

3

O

+

) concentration of the solution, we can plug this value into the formula.

p

H

=

log

[

1.00

×

10

4

M

]

p

H

=

4

The pH of this solution is 4.

Added notes:

p

H

=

p

H

3

O

+

because hydrogen ions attach to water molecules for form hydronium ions.

Some other key things to remember for pH calculations include:

pH + pOH = 14

pH = -log[

H

+

]

pOH = -log[

O

H

]

[

H

+

]

=

10

p

H

[

O

H

]

=

10

p

O

H

How many molecular of H2O and O2 are present in 8.5g of H2O2 ?​

Answers

2H2O+O2--->2H2O2  

8.5 gm H2O2=0.25 mole  

hence H2O is also 0.25 mole i.e.4.5 gm  

O2is 0.125 mole i.e.4 gm

effect of air and water on iron and zinc

Answers

Answer:

Rust

Explanation:

it does cool chemical things

`Answer is subscribe to XoX Snead on YT Explanation: b is the answer!!

In this equation, what does n represent?

OA number of electrons in the cell
OB number of electrons in the reactants
OC number of moles of electrons transferred
OD number of products in the equation
OE number of reactants in the quotient

Answers

Answer:

the number of electrons in the cell

If 46.3 grams of acetylene are required to run a carbide lamp for 8 hours, how many moles of water are required

Answers

Answer:

1.78 mol

Explanation:

Step 1: Write the balanced equation

CaC₂ + H₂O ⇒ C₂H₂ + CaO

Step 2: Calculate the moles corresponding to 46.3 g of C₂H₂

The molar mass of C₂H₂ is 26.04 g/mol.

46.3 g × 1 mol/26.04 g = 1.78 mol

Step 3: Calculate the moles of H₂O required to form 1.78 moles of C₂H₂.

The molar ratio of H₂O to C₂H₂ is 1:1. The moles of H₂O required are 1/1 × 1.78 mol = 1.78 mol.

For a reaction, AH = 176 kJ/mol and A SO = 0.285 kJ/(K•mol). At what
temperatures is this reaction spontaneous?
A. At no temperature
B. T< 50 K
C. T> 617 K
D. T< 617K

Answers

C trust meeeeeeeeeeer

Under the Controlled Substance Act (CSA), dispensing a controlled substance (CS) to the ultimate use includes ____________ (Select ALL that Apply)

Answers

Answer:.

pharmacies, prescribers, distributors/wholesalers, researchers, manufacturers, hospitals.

Explanation:

The Controlled Substance Act is a federal drug policy of the United States which regulates the manufacture, use, importation and possession and distribution of certain substances. It was enacted by the United States Congress in the year 1971.

Under the Controlled Substance Act, the dispensing of a controlled substance to the use includes pharmacies, prescribers, distributors/wholesalers, researchers, manufacturers, hospitals, etc.

How many grams of ammonia can be produced from reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm?

Answers

Answer: The mass of ammonia is 124457.96 g which can be produced from reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm.

Explanation:

Given: Volume = 450 L

Temperature = 450 K

Pressure = 300 atm

The reaction equation is as follows.

[tex]N_{2} + 3H_{2} \rightarrow 2NH_{3}[/tex]

Here, 1 mole of nitrogen reacts to give 2 moles of ammonia.

From the given data, moles of nitrogen are calculated as follows.

PV = nRT

where,

P = pressure

V = volume

n = no. of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into the above formula as follows.

[tex]PV = nRT\\300 atm \times 450 L = n \times 0.0821 L atm/mol K \times 450 K\\n = \frac{300 atm \times 450 L}{0.0821 L atm/mol K \times 450 K}\\= \frac{135000}{36.945}\\= 3654.08 mol[/tex]

For 3654.08 moles of nitrogen, the moles of ammonia produced is as follows.

[tex]2 \times 3654.08 mol\\= 7308.16 mol[/tex]

Therefore, mass of ammonia (molar mass = 17.03 g/mol) is calculated as follows.

[tex]Moles = \frac{mass}{molarmass}\\7308.16 mol = \frac{mass}{17.03 g/mol}\\mass = 124457.96 g[/tex]

Thus, we can conclude that the mass of ammonia is 124457.96 g which can be produced from reacting a 450 L sample of nitrogen gas at a temperature of 450 K and a pressure of 300 atm.

In many halocarbons, among them chloroethane (CH3CH2Cl), a halogen is attached to an aliphatic carbon chain. These halocarbons are called _____.

1.carboxylic acids
2.alkyl halides
3.aryl halides
4.phenyl halides

Answers

The answer is 1. Carboxylic acids

Which is TRUE about the structure of the atom? Select all that apply.

a
the densest part of the atom is the nucleus of the atom
b
the outermost part of the atom is where electrons are found
c
the nucleus of the atom is where protons and neutrons are found.
d
the outer part of the atom is called the antinucleus.
e
the nucleus of the atom has a diameter of about 10-10 m.

Answers

A. The densest part of the atom ie the nucleus of the atom

Freé point
[tex] \: \: \: \: \: \: [/tex]

Answers

Answer

Tq so much.

Pls follow me and Mark as brainliest Plsssssssss

Answer:

Thank you so much.

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