Aqueous solutions of lead nitrate and potassium iodide are combined in a test tube. The best proof that a chemical reactions has occurred would be that

Answer:

Mass percent = 5.44 %

Explanation:

Given data:

Mass of solute (NaCl) = 13.6 g

Mass of  solution = 250 g

Mass percent of solution = ?

Solution:

Formula:

Mass percent = mass of solute / mass of solution ×100

Mass percent = 13.6 g / 250 g × 100

Mass percent = 0.0544 × 100

Mass percent = 5.44 %

The mass percent of a solution containing 13.6 g of NaCl in 250.0 g of solution is 5.44%. This is calculated by dividing the mass of the solute (NaCl) by the total mass of the solution and multiplying by 100%.

The mass percent of a solution can be calculated by dividing the mass of the solute by the total mass of the solution and then multiplying by 100%. In this case, the solute is NaCl (sodium chloride), and the mass is 13.6 g. The total mass of the solution is 250.0 g. Mass-percent = (Mass of solute / Total mass of solution) × 100% = (13.6 g / 250.0 g)× 100% = 5.44%.

Therefore, the mass percent of the solution that has 13.6 g of NaCl in 250.0 g of the solution is 5.44%.

https://brainly.com/question/34428429

#SPJ11

Answer:A

Explanation:

Formula of equilibrium constant is product divide by reactant

Answer:

b) False

Explanation:

CI is the element symbol of Chlorine with an atomic mass unit of 35.5 amu and atomic number 17.

That's why the given statement is false.

The elements of group 17 are called halogens. These are six elements Fluorine, Chlorine, Bromine, Iodine, Astatine.

Chlorine is present below the bromine and have following properties:

Properties of Chlorine:

1. it is greenish-yellow irritating gas.

2. its melting point is 172.2 K

3. its boiling point is 238.6 K

4. it is disinfectant and can kill the bacteria.

5. it is also used in manufacturing of paper, paints and textile industries

Answer:

v = 450 m/s

Explanation:

Given data:

Frequency = 75 Hz

Wavelength = 6 m

Velocity = ?

Solution:

Velocity is the product of frequency and wavelength.

v = f × λ

v = 75 Hz ×  6 m

Hz = s⁻¹

v = 75  s⁻¹  ×  6 m

v = 450 m/s

Answer: 450

meters per second

Explanation:

Answer:

T₂ = 669.2 K

Explanation:

Given data:

Initial pressure = 660 torr

Initial temperature = 26 °C (26 +273 = 299 K)

Final volume = 280 mL ( 280/1000 = 0.28 L)

Final pressure = 940.0 torr

Final volume = 0.44 L

Final temperature = ?

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

P₁V₁/T₁ = P₂V₂/T₂  

T₂ = P₂V₂ T₁ /P₁V₁

T₂ = 940 torr × 0.44 L  × 299 K / 660 torr × 0.28 L

T₂ = 123666. 4 torr. L. K / 184.8 torr. L

T₂ = 669.2 K

Answer:

The phenomenon of marble cancer is due to ACID RAIN.

Explanation:

The marble corrosion is a process by which the marbles or limestone used in construction of monuments and buildings is corroded away by the acid rain.  The sulphur-dioxide and  nitrogen oxides present in the atmosphere undergoes certain chemical reaction causing this acid rain. These chemical in the acid rain converts the calcium  present in the limestone or marble into salt.

Also, this marble cancer leads to change the appearance and color. Sometime due to over corrosion the monuments or building causes them disintegrate .Tajmahal is one of the monument affected by marble cancer. the white color of tai mahal is slowly turning into yellow due to this marble cancer.

Answer:

The new pressure is 0.5852 bar

Explanation:

Since the temperature is constant, we can apply Boyle's Law.

Boyle's Law states that at constant temperature, pV = constant

[tex]p_{1}V_{1}=p_{2}V_{2}\\p_{1}=1.51\:bar\\V_{1}=224cm^{2}\\V_{2}=578cm^{2}\\Let\:p_{2}\:be\:the\:new\:pressure.\\p_{2}=\frac{p_{1}V_{1}}{V_{2}}=\frac{1.51\times224}{578}\\ p_{2}=0.5852\:bar[/tex]

Therefore, the new pressure is 0.5852 bar

Answer:

The discoverer of X-rays was Wilhelm Conrad Roentgen.

The discoverer of radioactivity was Henri Bacquerel.

Explanation:

Wilhelm Conrad Roentgen discovered X-rays in early 1895. Roentgen observed a fluorescent glow of crystals on a table near his tube when he was working with a cathode-ray tube in his laboratory, The Cathode ray tube consisted of a glass envelope with positive and negative electrodes encapsulated in it. When a high voltage was applied the air in the tube was evacuated and hence the tube produced a fluorescent glow.

Becquerel had discovered radioactivity in 1896. To study the properties of x-rays he was using naturally fluorescent minerals. He exposed potassium uranyl sulfate to sunlight and then on photographic plates wrapped in black paper, he placed this. He believed that suns's energy would be absorbed by uranium which would then produce X rays. Without any Solar energy  uranium emitted radiation because the images produce in this experiment were strong and clear.

Answer:

Option C. Time for one Earth rotation would double.

Explanation:

If the distance between Earth and Sun is increased up then it will decrease the gravitational pull of the Sun and hence will increase the orbital period of the Earth and will also increase the time taken for one Earth rotation because rotation of Earth is primarily depend on the external torque from the gravity of the Sun, Moon and other celestial bodies.

When someone’s immune system overreacts to something harmless it’s called C. An allergy

Allergies are a type of hypersensitivity reaction. This means that the immune system reacts to a substance that is harmless to most people. The substance that triggers an allergic reaction is called an allergen.

Allergens can be found in a variety of things, including pollen, dust mites, pet dander, and food. When an allergen enters the body, the immune system releases chemicals, such as histamine, to fight it off. These chemicals can cause a variety of symptoms, including sneezing, runny nose, itchy eyes, hives, and difficulty breathing.

Option C is correct.

Find out more on allergies at https://brainly.com/question/8106617

#SPJ6

Soil retains water and nutrients.

Several rocks rest in a stream.

Clouds create shade that changes temperatures

Abiotic factors are non-living components in the environment, or rather components in the environment that are not derived from life.

Explanation:

Abiotic factors interact with biotic factors to create ecoystems. An example of biotic factors interacting with abiotic factors include plants utilizing sunlight for photosynthesis and a wild beast drinking water form a watering hole in the middle of the savanna.

Learn More:

For more on biotic and abiotic factors check out;

https://brainly.com/question/11015328

https://brainly.com/question/11483587

https://brainly.com/question/1542938

https://brainly.com/question/12689972

https://brainly.com/question/935464

#LearnWithBrainly

Final answer:

Abiotic factors are nonliving elements in an environment such as soil, rocks, and clouds, and are essential in shaping ecosystems.

Explanation:

The abiotic factors in an environment include the nonliving components that shape the ecosystem. The statements that describe abiotic factors are:

These elements such as soil, rocks, and clouds are crucial in determining the overall health of the ecosystem and which organisms can survive there. On the other hand, chickens running around a farm and plants competing for sunlight are examples of biotic factors, as they involve living organisms interacting within their environment.

Answer:

44.46076 litres

Explanation:

Answer:

about 37.02 Liters

Explanation:

The conversion rate is about 3.785. 9.78*3.785~37.02

B

Relative to the observer, the objected, emitting visible light will appear red in color because the wavelength of light is stretched hence acquiring longer wavelength in the visible electromagnetic spectrum (remember red light has the longest wavelength in the visible light spectrum).

Explanation:

Conversely, if the object was moving towards the observer, it would appear blue in color (blue shift) because the relative wavelength of the visible light would be ‘compressed’ (remember this is always relative to the observer) hence the wavelength would be shorter (and blue light has the shortest wavelength in the visible light spectrum).

Both these phenomenons are classified under Doppler shift effect of waves. It also occurs in our daily lives. When a wailing ambulance approaches you, the pitch of the wailing sounds is higher (relative to you). However, when the ambulance passes you and begins stretching away from you, the pitch of the wailing goes low.

Learn More:

For more on Doppler shift effect check out;

https://brainly.com/question/3841958

#LearnWithBrainly

. It is called the blue shift, because the more compacted waves are shifted toward the blue end of the spectrum.

ITS B

Answer:

The configuration of the atom would be 2-8-2.

Explanation:

Any atom of an element combines with other element to complete its octet and become stable.

The electron configuration of the given atom is 2-8-6. That means the atom has 6 electrons in its outermost shell. To become stable the atom should have 8 electrons in its outermost shell. The given atom has 6 electrons so it either lose 6 electrons or gain 2 electrons to complete its octet.

But we know the atom having 5,6,7 electrons in its outermost shell they do not lose, they gain either 3 or 2 or 1 electrons to complete its octet.

So we say that atom with the electron configuration 2-8-6 bond with the atom having electron configuration 2-8-2.

A neutral atom with the electron configuration 2-8-6 would most likely form a bond with an atom having the configuration 2-5, such as a neutral nitrogen atom.

A neutral atom with the electron configuration 2-8-6 refers to an atom with 16 electrons. To determine the atom it would most likely form a bond with, we consider the octet rule which states that atoms are more stable when they have 8 electrons in their valence shell. Based on this rule, the atom with a configuration that would most likely form a bond with the given atom is an atom with 5 electrons in its valence shell, such as a neutral nitrogen atom with the electron configuration 2-5.

Coefficient 2 on HCl

Balanced equation: CuCl₂ + H₂S → CuS + 2HCI​

We are required to balance the chemical equation given;

CuCl₂ + H₂S → CuS + HCI​

In our case;

CuCl₂ + H₂S → CuS + 2HCI​

Answer:

Molarity =5.32 M

Explanation:

Given data:

Mass of glucose = 239 g

Volume = 250 mL (250 /1000 = 0.25 L)

Molarity = ?

Solution;

Formula:

Molarity = number of moles / volume in litter

Number of moles:

Number of moles = mass/ molar mass

Number of moles = 239 g / 180.2 g/mol

Number of moles = 1.33 mol

Molarity:

Molarity = number of moles / volume in litter

Molarity = 1.33 mol / 0.25 L

Molarity =5.32 M

Answer:

are similar in electronegativity

Explanation:

Polar covalent bond is formed by mutual sharing of electrons between two identical atoms or having small difference of electronegativity.

A  polar covalent bond is likely to form between two atoms that differ in electronegativity. The shared pair of electrons are attracted towards the more electronegative atom ad make a partial charge separation.

A covalent bond is formed between two non-metals through sharing of valence electrons between atoms. For example carbon and oxygen are non metals forming the covalent compound CO.

Electronegativity of an atom is its ability to attract the share pair of electrons towards its nucleus. Elements like oxygen, fluorine, nitrogen etc. are highly electronegative.

In a covalent compound, if the difference in electronegativity between two atoms is significant, the shared pair of electrons attracts towards the highly electronegative atom and resulting charge separation make them polar compounds.

Find more on covalent compounds:

https://brainly.com/question/21505413

#SPJ2

Answer:

carbon dioxide

Explanation:

Green spaces are important in cities because they reduce the carbon dioxide concentrations that are produced most by vehicular activity. At the same time, these green spaces provide the city with an invaluable source of oxygen that otherwise would not be found in city limits due to pavimentation and lack of naturally forested areas or green spaces.

Answer:

C. carbon dioxide and water

Explanation:

Water is a small molecule that easily diffuses through a cell membrane (osmosis) despite the lipid tails. Oxygen is a small molecule and it’s nonpolar, so it easily passes through a cell membrane. Carbon dioxide, the byproduct of cell respiration, is small enough to readily diffuse out of a cell.

In H2SO4, H is +1, S is +6, and O is -2; in CaSO4, Ca is +2, S is +6, O is -2; in HF, H is +1 and F is -1. These oxidation numbers follow standard rules based on the elements' positions in the periodic table and their common states in compounds.

To determine the oxidation numbers in the compounds H2SO4, CaSO4, and HF, we use the standard rules for assigning oxidation numbers.

These values follow from the rules that the oxidation number of hydrogen is usually +1, that of oxygen is usually -2, and the sum of oxidation numbers in a neutral compound must equal 0. Fluorine always has an oxidation number of -1 in its compounds.

Answer:

Eye colour is one example of a trait caused by the concentration of melanin in genes.

Explanation:

Eye colour is decided based on two distinct factors- pigmentation of the eye’s iris and scattering of the light by the 'stroma of the iris'. It is a 'polygenic phenotypic' character in a human being.  

The pigmentation of the iris varies between brown and  black, that all depends on melanin concentration in the iris stroma, iris pigment epithelium and the cellular density of trauma. Further, the eye colour genetics are complicated and multiple genes are responsible for same.

Final answer:

Eye color is an inherited trait determined by multiple genes and alleles, where certain alleles are dominant over others. A green-eyed child with brown-eyed parents suggests both parents are heterozygous for the green eye color allele. The pattern of inheritance is also influenced by epistasis and linkage.

Explanation:

Eye color is an example of a trait that is determined by multiple genes. In humans, eye color can be influenced by multiple alleles, where certain alleles are dominant over others. For example, the allele for brown eyes is dominant over the allele for blue eyes, meaning that a person with one copy of each allele will have a brown iris.

Moreover, the inheritance pattern of eye color is more complex due to the presence of epistasis, where the expression of one gene is influenced by one or more other genes. In the instance provided, a child with green eyes born to parents with brown eyes indicates that both parents carry the allele for green eyes, making them heterozygous. Therefore, choice b. Both parents are heterozygous, having the green trait on the green-blue eye gene, explains how this is genetically possible.

Answer:

4.13 g

Explanation:

Data Given:

Amount of CO₂ Produced = 15 g

Amount of Oxygen = 11 g

Amount of Carbon used = ?

Solution:

Suppose Carbon dioxide (CO₂) is formed by the reaction of carbon and oxygen then the reaction will be as below

                            C   +   O₂    -------------> CO₂

                          1 mol    1 mol                  1 mol

we come to know from the above reaction that

1 mole of carbon react with 1 mole of oxygen to produce 1 mol of carbon dioxide.

molar mass of C = 12 g/mol

molar mass of O₂ = 32 g/mol

molar mass of CO₂ = 12 + 2(16) = 44 g/mol

if we represent mole in grams then

           C               +                        O₂                     ------------->        CO                 1 mol (12 g/mol)                      1 mol (32 g/mol)                      1 mol (44 g/mol)

              C   +   O₂    -------------> CO₂

            12 g       32 g                   44 g

So,

we come to know that 32 g of Oxygen combine with 12 g  of oxygen produce 44 g CO₂

So now how much of Carbon will be combine with 11 g of oxygen

apply unity formula

                32 g of  O₂ ≅ 12 g of  C

                  11 g of O₂  ≅  g of  C

by doing cross multiplication

           g of C = 12 g x 11 g / 32 g

           g of C = 132 g / 32 g

           g of C = 4.13 g

So,

4.13 g of carbon will consume to produce 15 g of Carbon dioxide.

to check this answer

we use the above information

                     12 g of  C ≅ 44 g of CO₂

                     4.13 g of C ≅  g of  CO₂

by doing cross multiplication

                    g of  CO₂ = 44 g x 4.13 g / 12 g

                    g of CO₂ = 15g

So it is confirmed that

4.13 g of carbon will consume to produce 15 g of Carbon dioxide.

Answer:

V₂ =  1200 mL

Explanation:

Given data:

Volume of gas = 250 mL

Pressure of gas = 3.6 atm

Final pressure = 0.75 atm

Final volume = ?

Solution:

P₁V₁ = P₂V₂

V₂ = P₁V₁ /P₂

V₂ = 3.6 atm . 250 mL /0.75 atm

V₂ = 900 atm. mL /0.75 atm

V₂ =  1200 mL

Answer:

The radius of the sun is 7x10^5 kilometers, and that of the Earth is about 6.4x10^3 kilometers. Use scientific notation to show that the Sun's radius is about 100 times the Earth's radius. The Sun's radius is 10^10 the Earth's radius.

In scientific notation, the radius of the sun is 109 times the radius of the Earth.

The sun is almost a perfectly shaped sphere. The equatorial diameter and the polar diameter of the sun differ only by only 6.2 miles or 10 km. The sun's mean radius is 432,450 miles or 696,000 kilometers.

According to this, the diameter would be about 864,938 miles or 1.392 million km. Around 109 Earths could be lined across the face of the sun. The circumference of the sun is about 2,715,396 miles or 4,370,006 km.

Sun is the biggest thing in our neighborhood or in our solar system. But, compared to other stars that have been observed, the sun is called an average star. Betelgeuse, which is a red giant, is about 700 times bigger than the sun and 14,000 times brighter. The classification of the sun is as a G-type main-sequence star or a G dwarf star,  

Therefore, in scientific notation, the radius of the sun is 109 times the radius of the Earth.

Read more about the size of the sun, here

https://brainly.com/question/2455981

#SPJ2

“Water” is the best thermal insulator.

Option: B

Explanation:

“Thermal insulators” are the materials which do not allow heat to transfer. “Water” is the substance which does not transfer heat. Hence, the “water” is the best “thermal insulator”. Water is the bad conductor of thermal heat. Water has “low thermal conductivity” than other substances, so this acts as an insulator as long as it is not traveled from one place to another. Heat is transferred when a “hot object collides” with “the cold objects”. The “thermal conductivity” of “water” is 0.6 W/m K.

Answer:

Increasing order of Electronegativity:

Neon < Aluminum < Sulfur <Oxygen

0 < 1.61 < 2.58 < 3.44

Explanation:

Electronegativity:

Electronegativity is the power of an atom to attract shared pair of electron in a bond.

Trend in Periodic Table:

Electronegativity of the following Compounds is

1. Electronegativity of sulfur:

Sulfur is in group 4 and its

EN of Sulfur = 2.58

2. Electronegative of oxygen:

Oxygen is in group VIA and much electronegative than Sulfur.

The EN oxygen = 3.44  

3. Electronegative of Neon:

Neon is group VIIIA member and most stable element thats why have it have no data for electronegativity.

The EN of Neon = 0

4. Electronegative of Al:

It is group IIIA member and have less electronegativity

The EN of Aluminum= 1.61

So the Increasing order of electronegativity is

Neon < Aluminum < Sulfur <Oxygen

The order of increasing electronegativity for aluminum, sulfur, oxygen, and neon is: aluminum < sulfur < oxygen < neon. This order is determined by the increasing concentration of positive charge in the nucleus and the arrangement of electron configurations.

The elements in question, sulfur, oxygen, neon, and aluminum, can be ranked in order of increasing electronegativity by looking at their positions on the periodic table. Electronegativity increases from left to right across a period, and from bottom to top in a group. Thus, the order of increasing electronegativity would be as follows: aluminum < sulfur < oxygen < neon. This is due to the electron configurations of these elements as well as the increasing concentration of positive charge in the nucleus as one moves from left to right in a period and downward across a group.

https://brainly.com/question/10531792

#SPJ3

Fission is the process where nuclei:

    Split to form smaller nuclei.

Fusion is the process where nuclei:

    Combine to form larger nuclei.

A easy way to remember which is which is by remembering that to fuse two things together is to combine them to make a single entity, and fusion is the process of fusing nuclei together. And if you know that, then you will know that fission is the process of splitting nuclei.

Fusion: Combine

Fission: Split

I hope this helps. Let me know if you have any questions or if anything confuses you. :)

Answer:

A. Si-28

B.Fe-56

Explanation:

Answer:

a. ²⁸₁₄Si, Silicon-28

b. ⁵⁶₂₆Fe, Iron-56

Explanation:

a. For the nuclear symbol, the mass number of the isotope is on top while the atomic number is at the bottom. For example, ²⁸₁₄Si. The hypen notation for the isotope is Silicon-28 based on the atomic number and mass number.

b. The mass number of the isotope is equal to the sum of protons and neutrons = 26+30 = 56. The atomic number is the number of protons = 26. Thus, the nuclear symbol is ⁵⁶₂₆Fe and the hypen notation is Iron-56.

Answer: Sensory neurons are nerve cells within the nervous system responsible for converting external stimuli from the organism's environment into internal electrical impulses. For example, some sensory neurons respond to tactile stimuli and can activate motor neurons in order to achieve muscle contraction.

Explanation:

Answer:

Sensory neurons are what is known as the nerve cells. They are found within the nervous system. They respond to tactile stimuli and can activate motor neurons in order to achieve muscle contraction.

The modern periodic table is arranged by increasing atomic number, which corresponds to the number of protons in an atom. Each box represents an element and displays various details about it. The table also shows patterns and periodic trends in the properties of elements.

The modern periodic table is primarily arranged by increasing atomic number, which directly corresponds to the number of protons in an atom. The table is composed of rows (periods) and columns(groups). Elements that share many of the same chemical properties are grouped into the same columns. As we traverse each period from left to right, a proton is added to the nucleus and an electron to the valence shell of each successive element. The trend changes as you go down a group; the number of electrons in the valence shell remains constant, while the principal quantum number increases by one each time.

Each box in the table represents an element and includes its atomic number, symbol, average atomic mass, and sometimes its name. Elements are arranged in seven horizontal rows and 18 vertical columns. Patterns in chemical properties are also observable in the periodic table. For instance, as we move down a group, the metallic character of the elements increases, signifying a periodic trend in the elements' properties.

https://brainly.com/question/35897164

#SPJ11