1 point
7) While preparing a temporary mount of cheek cells, teacher asked Rohit
to pick up the stain. He had four bottles A, B, C and D containing Methylene
blue, glycerin, distilled water, Canada balsam respectively. Which one
should he pick? *
А
B
C
D

Fogging a mirror with your breath is a physical change because it involves a phase change of water vapor condensing and adsorbing to the mirror surface. Phase changes are physical changes.

Breaking a bone is a physical change insofar as we're focusing on the  "breaking" part.

Mending a broken bone, however, is a different story. Bones are living things: They consist of tissues that in turn consist of cells. The actual mending process involves some very complicated biochemistry. Suffice it to say that mending a broken bone would be a chemical change.

Burning paper is a chemical change. Burning anything implies combustion, which is a chemical reaction where some fuel is oxidized (usually by oxygen gas, producing carbon dioxide gas and water vapor).

Slicing potatoes for fries is a physical change. You can slice, dice, smash, mash, stretch, bend, compress, or grind a potato: What you will have is still a potato (okay, there are some chemical changes going on as you're rupturing cells in the process, causing them to release their contents which may participate in chemical reactions). But the key, again, is that cutting up some material doesn't fundamentally change the chemical identity of that material.

Mixing sugar with coffee actually involves two physical processes: the mixing and the (presumed) solvation of the solid sugar particles as they dissolve into the coffee. In either case, either mixing or dissolving would be a physical change. The sugar molecules are still in the coffee and are chemically unchanged.

Frying chicken is a chemical change. In fact, frying chicken likely entails several different types of chemical changes. The common thread among them is that frying involves breaking chemical bonds in and on the chicken by the addition of thermal energy, and new chemical bonds end up being formed. That's the hallmark of a chemical change.

A nail rusting is a chemical change. Rusting is an electrochemical process; the familiar corrosion of iron into rust is, at bottom, a chemical reaction where iron reacts with oxygen to form iron oxides (often catalyzed by the presence of water and salts).

A paper ripping is analogous to slicing potatoes: it's a physical change. If you ripped one sheet of paper into two halves, each half would retain all the chemical properties of the original sheet.

Likewise, wood burning is analogous to burning paper, and as such is a chemical change. Again, combustion is a chemical process.

As we said earlier with sugar in coffee, mixing in itself is a physical process. While it may seem like you've permanently changed the nature of the water by dyeing it with food coloring, the molecules comprising the food coloring are simply dispersed within the vast sea of water molecules. There are no intramolecular bonds that are broken or formed; the chemical identities of all the substances here are preserved. So, this is a physical change.

Food molding (rotting) is a chemical change. Rotting is biochemical decomposition: the chemical bonds that make up the food are broken down by enzymes released by the mold.

Writing on paper, whether it be with a pen, pencil, crayon, or marker, is a physical change. The molecules from the writing instrument are physically stuck to the paper. But unless you're writing on paper by, say, burning letters onto it, there are no chemical changes occurring when the writing instrument meets the paper.

As with writing on paper, dyeing fabric can be a physical change. The dye consists of molecules that interact with light in a way that we perceive a certain color. When dyeing fabric, these molecules are transferred and fixed into the fabric by adsorption, absorption, and other intermolecular phenomena. But the molecules of the dye (and the molecules in the fabric) don't experience any breaking and forming of bonds. All of the substances involved retain their chemical identities.

However, it's possible that, depending on the dye, there may be chemical changes involved. Some dyes, appropriate named "reactive dyes," undergo chemical reactions with their substrate (which, in this case, would be the fabric), or dyes may be used that undergo chemical reactions with one another, both of which would constitute chemical changes. And it can depend on what you mean by "dyeing": Bleaching a colored shirt can technically be conceived of as "dyeing" the shirt white, and this process involves cleavage of bonds within the color-producing molecules in the fabric by reacting with the molecules in the bleach.

So, for dyeing fabric, it can be a physical or chemical change depending on the dye.  

Answer:

The half-life of Th-232 is 1.4 ∙ 10¹⁰ years.

Answer:

s+o2=so2

Explanation:

i hope it will help u

Answer:

The  electronegativity   of fluorine  compare  to the  electronegativity   of oxygen and chlorine as below

Explanation:

Fluorine  has the highest electronegativity than oxygen, and  chlorine.

 Explanation

Generally  the  electronegativity  increase   across the period ( from the left to the right)  and  decreases down  the group.

Both oxygen and fluorine  are in period 2   in  periodic   table. since  fluorine is on  fur  right side as compared to oxygen , fluorine has higher  electronegativity than  oxygen.

On the  other side  Fluorine  and  chlorine are  in the same group in periodic table. fluorine  is at  the top of  the group  while chlorine  is at  the bottom therefore fluorine has  higher electronegativity  than chlorine.

Answer:

[tex]\boxed {\boxed {\sf 0.5043 \ mol \ P}}[/tex]

Explanation:

To convert from moles to grams, we must use the molar mass. This is found on the Periodic Table. Look for Phosphorous or P.

We can use this number as a ratio.

[tex]\frac{30.973762 \ g \ P }{1 \ mol \ P}[/tex]

Multiply by the given number of grams: 15.62

[tex]15.62 \ g \ P *\frac{30.973762 \ g \ P }{1 \ mol \ P}[/tex]

Flip the fraction so the grams of phosphorus cancel.

[tex]15.62 \ g \ P *\frac{1 \ mol \ P}{30.973762 \ g \ P }[/tex]

[tex]15.62 *\frac{1 \ mol \ P}{30.973762 }[/tex]

[tex]\frac{15.62 \ mol \ P}{30.973762 }[/tex]

Divide.

[tex]0.504297799 \ mol \ P[/tex]

The original measurement of grams has 4 significant figures, so our answer must have the same.

For the number we calculated, that is the ten thousandth place. The 9 in the hundredth thousandth place tells us to round the 2 to a 3.

[tex]0.5043 \ mol \ P[/tex]

There are 0.5043 moles of phosphorus in 15.62 grams.

Answer:

A. He sent a cathode ray between electrically charged metal plates

Answer:

Given

mass of H2O (m) =35.6g

molarmass (mr) = H2O ), 1x2+16=18g/mol

moles of H2O (n) =?

sln

n=m/mr

n=35.6g/18g/mol

n=1.978moles

the moles of H2O are 1.978moles

Answer:

116g/mol

Explanation:

Mg=24

NO2=46

multiple 46 by 2and then add 24

The molar mass of  Mg(NO₂)₂ is  116.33 g/mol.

To calculate the molar mass of Mg(NO2)2, we need to determine the atomic masses of each element in the compound and multiply them by their respective subscripts.

The atomic masses of the elements involved are:

Mg (magnesium) = 24.31 g/mol

N (nitrogen) = 14.01 g/mol

O (oxygen) = 16.00 g/mol

The compound Mg(NO₂)₂ contains one magnesium atom (Mg), two nitrate ions (NO₂), and each nitrate ion contains one nitrogen atom (N) and two oxygen atoms (O).

Molar mass of Mg(NO₂)₂ :

Mg: 1 × 24.31 g/mol = 24.31 g/mol

N: 2 × 14.01 g/mol = 28.02 g/mol

O: 4 × 16.00 g/mol = 64.00 g/mol

Now, add up the individual masses:

24.31 g/mol + 28.02 g/mol + 64.00 g/mol = 116.33 g/mol

Therefore, the molar mass of Mg(NO₂)₂  is 116.33 g/mol.

Learn more about molar mass here:

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Answer:

ion

Explanation:

that is the definition according to g o o g l e:

"an atom or molecule with a net electric charge due to the loss or gain of one or more electrons."

Answer:

An ION

Explanation:

Because a positive ion is called a CATION and a negative ion is called an ANION (Please brainlist me)

Answer:

ch20 is the empirical formula for glucose , c6h1206 is the molecular formula .

Answer:

C. Tubes 2, 3, and 4

Explanation:

Tube one doesn't contain an organism so it can't be that one.

Both a snail and an elodea are considered an organism, cellular respiration occurs in almost any organism's cells.

good luck, i hope this helps :)

Answer:

5

Explanation:

20/4

Answer:

Explanation:

The bond angle is said to be the angle between two atoms near or around the same atom for a given covalent compound. However, a dihedral angle is known as the angle formed between two planes. Bond angles are usually planar while dihedral angles are interplanar.  

The diagram below shows the structure of each compound.

Answer:

These currents are on the ocean's surface and in its depths, flowing both locally and globally. Winds, water density, and tides all drive ocean currents. Coastal and sea floor features influence their location, direction, and speed. Earth's rotation results in the Coriolis effect which also influences ocean currents. -

Answer: The Coriolis effect

Explanation:

Answer: signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color change, formation of a precipitate, formation of a gas, odor change, temperature change.

Explanation:

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Sulfur is not nearly as electronegative as oxygen so that hydrogen sulfide is not nearly as polar as water. Because of this, comparatively weak intermolecular forces exist for H2S and the melting and boiling points are much lower than they are in water.

The boiling point of hydrogen sulfide is low because the oxygen atom was stronger electronegative than that of the Sulphur atom, water would be more polar than hydrogen sulphide.

If a molecule does have more positive charges on one end than negative charges on the other, an electrical pole has been created. This is how polar molecules are typically formed.

What is boiling point?

The temperature where a liquid's vapor pressure reaches the pressure around it as well as the liquid transforms into a vapor is known as the boiling point of a substance.

The boiling point of hydrogen sulfide is low because the oxygen atom was stronger electronegative than that of the Sulphur atom, water would be more polar than hydrogen sulphide. Additionally, hydrogen sulphide has a lesser melting point as well as boiling point than water due to poor intermolecular forces (dipole forces, Vander Waal's forces).

To know more about polar molecule and boiling point

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Answer:

16

Explanation:

Answer:

its 16

Explanation:

i took the quiz and it was right

Answer:

D

Explanation:

Answer:

Explained below

Explanation:

Fossil fuels which are made up of coal and oil when burnt by power-production industries, make sulfur to be released into the atmosphere where it combines with oxygen to form SO2 (sulfur Dioxide). Now, the exhausts possessed by cars could also cause the formation of nitrogen oxides in the atmosphere. Therefore, H2SO4 which is airborne sulfuric acid and HNO3 which is nitric acid can be formed and when dissolved in the water vapor in the atmosphere form what is called acid rain.

Now, as acid rain flows through the soil, it can leach aluminum from the soil clay particles and then flow into the lakes to make them more acidic.

Answer:

1 ans:  d. all seeds has young plant, stored food and a seed coat.

2 ans: d. the right pollen is placed on their stigmas

3 ans: a. pollen grain falls on a pistil

4 ans: a. fire

5 ans: b. sexual

Hope it helps,

Please mark me as brainliest

Thank you...

Answer:

4092 atoms of iron i am guessing

Explanation:

Answer:

Contact

Explanation:

As the speed of the particles increases, they move around more, which means they hit the sides of the container more.

Answer:

1429.32 mmHg

Explanation:

Initial Pressure P1 = 3000.0mmHg

Initial Temperature T1 = 500.0°C + 273 = 573 K ( Converting to kelvin temperature)

Final Temperature T2 = 0.00°C + 273 = 273 K ( Converting to kelvin temperature)

Final Pressure P2 = ?

The pressure of a given amount of gas is directly proportional to the absolute temperature provided volume remains constant.

This is given by the mathematical expression;

P1 / T1  = P2 / T2

Inserting the values;

3000 / 573 = P2 / 273

P2 = 273 * 3000 / 573

P2 = 1429.32 mmHg

Answer:

d. The correct answer for your questions is Sr<Ca<Be

Answer:

Answer:- choice d is correct. Sr<Ca<Be .

Explanations:- Br, Ca, and Sr are all elements of same group as they all have 2 valence electrons. As we move down in a group, a new shell is being added that increases the size of the atom. As the size of an atom increases, it is easy to remove the electron from it's outer most shell in it's gaseous state. Since, Be is above Ca and Ca is above Sr. The size increases in the order, Be < Ca < Sr. It means Be is the smallest one of them and so it's hard to remove from it's outer most shell and hence it's ionization energy is higher.

Sr is largest one in these three elements and so it's easy to remove outer most electron from it that means the ionization energy is least. Ca is between Be and Sr.

So, an increasing order of ionization energy is Sr<Ca<Be . Choice D is correct.

Answer:

64cm^3

Explanation:

To get the volume just multiple 4*4*4

Answer:

[tex]q=8\times 10^{-19}\ C[/tex]

Explanation:

Given that,

The charge of a single proton is [tex]1.6\times 10^{-19}\ C[/tex]

There are 5 protons in the nucleus. The nuclear charge of an atom of boron is given by :

[tex]q=5\times 1.6\times 10^{-19}\\\\q=8\times 10^{-19}\ C[/tex]

So, the required charge is [tex]8\times 10^{-19}\ C[/tex].

Answer:

i think it's B

Explanation: