Why does water freeze at a temperature lower than 0°c when salt is added to it.

Answer:

1. highest is 25.7c° and lowest is 20.0c°

2.Is Exothermic.  An Endothermic Reaction is a chemical reaction that absorbs energy in the form of light or heat. In it, the energy or enthalpy of the reactants is less than that of the products. An Exothermic Reaction is a chemical reaction that gives off energy in the form of light or heat.

3. Reactans.

4. The substance(s) to the left of the arrow in a chemical equation are called reactants. A reactant is a substance that is present at the start of a chemical reaction. The substance(s) to the right of the arrow are called products . A product is a substance that is present at the end of a chemical reaction.

Answer:

Homeostasis to photosynthesis and anaerobic respiration to aerobic respiration.

Answer:

It is a type of radiant energy that's invisible to human eyes but that we can feel as heat.

Ques.1: Why do you think that you had to use a thin layer of onion skin, rather than a thick layer for the microscope?

Ans:- It is because, I the onion peel is thick layered, then it will be hard or impossible to see through the microscope.

Ques.2: When iodine reacts with starch, it produces a blue-black color. Starch is a white substance which plants use to store food. What structure did you see better because of the iodine? Why did you see this structure better?

Ans: Amylose in starch is responsible for the formation of a deep blue color in the presence of iodine. The iodine molecule slips inside of the amylose coil.

This makes a linear triiodide ion complex with is soluble that slips into the coil of the starch causing an intense blue-black color.

Due to this, we can see the structure better.

Ques.3: From low power to high power, what structures became clearer in the stained onion tissue?

Ans: From lower to higher power, we can see:-

-- Large, rectangular interlocking cells,

-- Clearly visible distinct cell walls surrounding the cells,

-- Dark stained nucleus,

-- Large vacuoles at the center,

-- Small granules may be observed inside the cells (within the cytoplasm)

Ques.4: What is the shape of an onion cell?

Ans: The shape of an onion cell is rectangular or square in shape.

Answer:

B. Biosphere

Explanation:

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Answer:

O=c=o

Explanation:

co2is nonpolar and it has linear molecular shape

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[tex] \huge\blue{Given}[/tex]

molar mass of CCl4 = 154

density = 1.59 g/cm³

volume = 10 liters

[tex]\huge{\color{magenta}{\fbox{\textsf{\textbf{Solution}}}}}[/tex]

[tex]mass = \frac{density}{volume} \\ mass = \frac{1.59}{10 \times 1000} \\ mass \: = \: 1.59 \times {10}^{ - 4} \\ \\ moles = \frac{mass}{molar \: mass} \\ moles = 0.01 \times {10}^{ - 4} [/tex]

Answer:

Explanation:

Pencils are though formed of wood that acts as a bad conductor of electricity, quite strangely pencils can be electrically charged.

Here pencils have non-metal carbons present in its graphite tip and this makes the pencils charged.

When this pencil is held near the water of the tap, the hydrogen ions get attracted and thereby the water gets attracted to the pencil.

Water, however, is an excellent conductor of electricity and therefore water and electricity are a dangerous combination.

Answer:

Paracetamol

Formula

C8H9NO2

Answer:

Explanation:

2,4 di methyl means that there are 2 methyl groups on the 2 and 4 carbons. hexane means there are 6 carbons in total for the carbon chain

first pic

3,3 diethyl means there are 2 ethyl groups on the 3 carbon chain. 4 mthyl means 1 methyl group on the 4 carbon chain, 5 propyloctane means that there are 1 propylo on the 5 carbon chain. and that the carbon chain is a octane meaning 8 carbons.

second pic

Answer:

36. B, LATTICE

35. A, COVALENT

38. B, TRIPLE COVALENT

Explanation:

36: Lattice- Sodium chloride is taken as a typical ionic compound.

35. covalent - the interatomic linkage that results from the sharing of an electron pair between two atoms. The binding arises from the electrostatic attraction of their nuclei for the same electrons.

38. TRIPLE COVALENT- because each nitrogen atom needs three electrons to fill its outermost shell.

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I hope it help

When the compound shown is treated CH3MgI followed by water, 1,3 - cyclohexadienol is formed.

Grignard reagent is an alkylmagnesium halide. Grignard reagents are important synthetic tools in chemistry. They are used to synthesize and number of compounds in the laboratory.

When the Grignard reagent, CH3MgI is reacted with compound shown followed by treatment with water, the product of the reaction is 1,3 - cyclohexadienol whose structure is shown in the second image attached to this answer.

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Answer:

please mark as brainliest

Explanation:

Any substance that inhibits the growth and replication of a bacterium or kills it outright can be called an antibiotic. Antibiotics are a type of antimicrobial designed to target bacterial infections within (or on) the body. This makes antibiotics subtly different from the other main kinds of antimicrobials widely used today:

Antiseptics are used to sterilise surfaces of living tissue when the risk of infection is high, such as during surgery.

Disinfectants are non-selective antimicrobials, killing a wide range of micro-organisms including bacteria. They are used on non-living surfaces, for example in hospitals.

Of course, bacteria are not the only microbes that can be harmful to us. Fungi and viruses can also be a danger to humans, and they are targeted by antifungals and antivirals, respectively. Only substances that target bacteria are called antibiotics, while the name antimicrobial is an umbrella term for anything that inhibits or kills microbial cells including antibiotics, antifungals, antivirals and chemicals such as antiseptics.

Most antibiotics used today are produced in laboratories, but they are often based on compounds scientists have found in nature. Some microbes, for example, produce substances specifically to kill other nearby bacteria in order to gain an advantage when competing for food, water or other limited resources. However, some microbes only produce antibiotics in the laboratory

Answer:

Antibiotics commonly are produced by soil microorganisms and probably represent a means by which organisms in a complex environment, such as soil, control the growth of competing microorganisms. Microorganisms that produce antibiotics useful in preventing or treating disease include the bacteria and the fungi.

Explanation:

source: trust me bro

Answer:

Box#:

1:CoS

2:Co2S3

3:CoSO4

4:Co2(SO4)3

5:CoSO3

6:Co2(SO3)3

Explanation:

1:Co(II) is -2 and S is -2, so the charges cancel

2:Co(III) is -3 and is -2, so you cross the charges but do not reduce

3:Co(II) is -2 and SO4 is -2, so the charges cancel

4:Co(III) is -3 and SO4 is -2 so the charges cross but do not reduce

5:Co(II) is -2 and SO3 is -2 so the charges cancel

6:Co(III) is -3 and SO3 is -2 so the charges once again cross

Answer:

Cobalt (II) sulfide → CoS

Cobalt (III) sulfide → Co₂S₃

Cobalt (II) sulfate → CoSO₄

Cobalt (III) sulfate → Co₂(SO₄)₃

Cobalt (II) sulfite → CoSO₃

Cobalt (III) sulfite → Co₂(SO₃)₃

Answer: 0.023 moles of CaO.

Explanation:

The balanced equation tells us that we'll get 2 moles of CaO for every one mole of O2.  Since we have 0.046 moles of O2, we'll get 0.023 moles of CaO.  (2 sig figs)

Answer:

Incase you have H and F and another H and F

Answer:

Ionic bonds result from the transfer of electrons from one atom to another

Explanation:

In covalent bonds, atoms share electrons, whereas in ionic bonds atoms transfer electrons. The reaction components of covalent bonds are electrically neutral, whereas for ionic bonds they are both charged.Covalent bonds are formed between two non-metals, whereas ionic bonds are formed between a metal and non-metal.  

Answer:

Covalent bonds are defined as sharing of electrons, ionic bonds are the result of transferred electrons;

Covalent bonds form between non-metals (elements) and ionic bonds form between metal and non-metals (ions)

When tiny droplets of one liquid are finely dispersed within another liquid it is called emulsion.

Emulsion can be defined as the process by which two liquids that are not miscible come together to form a mixture.

The emulsion mixture usually consists of an oil phase and a water phase.

The oil phase appears as droplets when dispersed (mixed with) the water phase.

The uses of emulsion include:

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We know that water is tasteless, odorless, and transparent. In small quantities, it is also colorless. However, when a large amount of water is observed, as in a lake or the ocean, it is actually light blue in color. The blue hue of water is an intrinsic property and is caused by selective absorption and scattering of white light. These and other properties of water depend on its chemical structure.The transparency of water is important for organisms that live in water. Because water is transparent, sunlight can pass through it. Sunlight is needed by water plants and other water organisms for photosynthesis.Chemical Structure of WaterEach molecule of water consists of one atom of oxygen and two atoms of hydrogen, so it has the chemical formula H2O. The arrangement of atoms in a water molecule explains many of water’s chemical properties. In each water molecule, the nucleus of the oxygen atom (with 8 positively charged protons) attracts electrons much more strongly than do the hydrogen nuclei (with only one positively charged proton). This results in a negative electrical charge near the oxygen atom (due to the "pull" of the negatively charged electrons toward the oxygen nucleus) and a positive electrical charge near the hydrogen atoms. A difference in electrical charge between different parts of a molecule is called polarity. A polar molecule is a molecule in which part of the molecule is positively charged and part of the molecule is negatively charged.

•Hydrogen Bonding-

Opposite electrical charges attract one another. Therefore, the positive part of one water molecule is attracted to the negative parts of other water molecules. Because of this attraction, bonds form between hydrogen and oxygen atoms of adjacent water molecules. This type of bond always involves a hydrogen atom, so it is called a hydrogen bond. Hydrogen bonds are bonds between molecules, and they are not as strong as bonds within molecules. Nonetheless, they help hold water molecules together.

•Sticky, Wet Water-

Water has some unusual properties due to its hydrogen bonds. One property is cohesion, the tendency for water molecules to stick together. The cohesive forces between water molecules are responsible for the phenomenon known as surface tension. The molecules at the surface do not have other like molecules on all sides of them and consequently they cohere more strongly to those directly associated with them on the surface. For example, if you drop a tiny amount of water onto a very smooth surface, the water molecules will stick together and form a droplet, rather than spread out over the surface. The same thing happens when water slowly drips from a leaky faucet. The water doesn't fall from the faucet as individual water molecules but as droplets of water.

•Density of Ice and Water-

The melting point of water is 0°C. Below this temperature, water is a solid (ice). Unlike most chemical substances, water in a solid state has a lower density than water in a liquid state. This is because water expands when it freezes. Again, hydrogen bonding is the reason. Hydrogen bonds cause water molecules to line up less efficiently in ice than in liquid water. As a result, water molecules are spaced farther apart in ice, giving ice a lower density than liquid water. A substance with lower density floats on a substance with higher density. This explains why ice floats on liquid water, whereas many other solids sink to the bottom of liquid water.In a large body of water, such as a lake or the ocean, the water with the greatest density always sinks to the bottom. Water is most dense at about 4°C. As a result, the water at the bottom of a lake or the ocean usually has temperature of about 4°C. In climates with cold winters, this layer of 4°C water insulates the bottom of a lake from freezing temperatures. Lake organisms such as fish can survive the winter by staying in this cold, but unfrozen, water at the bottom of the lake.

Hope it helps

Answer:

Robert Boyle

Explanation:

En muchos textos se suele considerar a Robert Boyle como el científico que introdujo en la Química un concepto de elemento diferente al empleado por los aristotélicos o por los alquimistas y que sirvió de antecedente al que formulara Lavoisier en 1789.

Answer:

Tthe 3-carbon pyruvate molecule made in glycolysis loses a carbon to produce a new, 2-carbon molecule called acetyl CoA. The carbon that is removed takes two oxygens from pyruvate with it, and exits the body as carbon dioxide (CO 2​start subscript, 2, end subscriptt).

Explanation:

Answer:

Nuclear transmutation

Explanation:

The process in which an element spontaneously transforms into another isotope of the same element, or into a different element is called nuclear transumutation. It occurs when the number of protons or neutrons in the nucleus of an atom is changed.

Answer: false

Explanation:

Answer:

B

Explanation:

The frequency of yellow light, which has a wavelength of 5.56 x 10^-7 m is  5.40 x 10^14 Hz. Therefore, option B is correct.

The distance between identical points (adjacent crests) in adjacent cycles of a waveform signal propagated in space or along a wire is defined as the wavelength. This length is typically specified in wireless systems in meters (m), centimeters (cm), or millimeters (mm) (mm).

The wavelength is the distance between two wave crests, and it is also the distance between two wave troughs. The frequency is measured in cycles per second (Hz) and is the number of vibrations that pass over a given spot in one second (Hertz).

Speed is distance over time, Therefore, v = λ / T.

The frequency, f, is 1/T, so the equation relating wave speed, frequency, and wavelength is v = c / λ .

Given :

Wavelength = 5.56 x 10^-7 m

Frequency = ?

Speed (c) = 3 × 10⁸m/s

v = c / λ

By substituting given values in equation and we get,

v =  3 × 10⁸ / 5.56 x 10^-7

= 5.40 x 10^14

The frequency of yellow light is 5.40 x 10^14.

Thus, option B is correct.

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Answer: Na2SO4

The molecular formula for sodium sulphur and oxygen​ is: (Na2SO4)

,  Hope this helps :)

Have a great day!!

Explanation:

Mix cold water and flour in a jar. Stir very well. After a few minutes, you can see sediments

at the bottom of the jar. How could you separate the sediments from the water?

3. After the members of the family ate different kinds of fruits, you gathered the seeds. You

mixed them in a basin. Later on, your mother instructed you to separate each kind of seed.

How will you separate each kind of seed?

4. Mix sand and water in a basin. After five minutes, try to separate the sand from the water.

How will you do this?

5. Dissolve one teaspoon of sugar in a cup of water (mixture of solid and liquid.) After three

minutes, separate the sugar from the water. How will you do it?

SANA PO MASAGOTAN NYU NG TAMA

Answer:

25.1 moles

Hence it can be seen that when 25.1 moles of carbon dioxide gas react with excess hydrogen gas, 25.1 moles of methane gas are produced.