first one is the answer

Answer:

Platinum is especially good for this because it is unreactive, and does not produce a color in the flame which will mask the presence of other metals.

Hope this answer is right!

Answer:

Hey mate, here is your answer

1. Platinum doesn't impart any color to the flame.

2. It is not oxidised under the high temperature of the flame from a bunsen burner.

3. It is almost chemically inert. Even at high temperatures, it remains unattacked by free radicals / acid radicals.

Therefore, platinum wire is crucial for a flame test. Also, a platinum wire should be thoroughly cleaned before using it for a new flame test.

A platinum wire is cleaned by dipping it into concentrated HNO3 and then placing it in the non luminous part of the bunsen flame. Otherwise, the perviously tested radicals will impart color to the flame, which may cause confusion.

Explanation:

Hope it helps you

10.0 trillion DNA molecules is equal to 1.66 × 10–11 moles of DNA.

The correct option is A.

The directions needed for a creature to grow, endure, and reproduce are encoded in its DNA. DNA sequences must be converted into messages that can be utilized to create proteins, that are the complex molecules that carry out the majority of the work in our bodies, in order to perform these activities.

The DNA of a person can be found in almost all of their cells. The majority of DNA is found in the cell nucleus (where it is known as nuclear DNA), but there is also a tiny quantity of DNA in the mitochondrial .

1 trillion = 10¹² DNA molecules

6.022 × 10²³ molecule = 1 mole

10¹² DNA molecules = 1 / 6.022 × 10²³ × 10¹²

                                 = 1.66 × 10–11 moles.

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The complete question is -

10.0 trillion DNA molecules is equal to how many moles of DNA?

A-1.66 × 10–11 moles

B-6.02 × 1010 moles

C-6.02 × 1036 moles

D-1.66 × 1010 moles

Answer:

B. trough to trough is NOT an accurate way to measure wavelength.

Explanation:

The correct way to measure wavelength is from crest to crest or from trough to trough, as these are the points of maximum displacement in the wave. Alternatively, one could measure from a point halfway between two crests (or two troughs) to another point halfway between the next two crests (or troughs), which is known as half crest to half crest measurement.

The accurate ways to measure the wavelength of a wave are between two crests (crest to crest), two troughs (trough to trough), or half crest to another half crest. Measuring from a crest to a trough gives half the wavelength. Therefore, option A (crest to trough) is not an accurate way to measure wavelength.

In the context of wave physics, the accurate ways to measure the wavelength of a wave are between two successive crests (crest to crest), or two troughs (trough to trough). The measurement from a half crest to another half crest is also valid, as it essentially represents the same distance as from crest to crest or trough to trough. However, measuring from a crest to a trough does NOT give you the wavelength, but instead it gives you half the wavelength because a complete wave cycle is from crest to crest or trough to trough. Therefore, option A (crest to trough) is NOT an accurate way to measure wavelength.

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The new lowered freezing point of the benzene mixture is determined as 2.4°C.

The presence of impurities lowers the vapour pressure of the solution since the concentration of the solution is increased.

Change in temperature of the new mixture = 0.613 x 5.5°C = 3.1 °C

New freezing point = 5.5°C - 3.1°C = 2.4°C

Thus, the new lowered freezing point of the benzene mixture is determined as 2.4°C.

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Answer:

B. Chlorine has more than one stable isotope that occurs naturally.

D. As fluorine only has one isotope the atomic mass is identical to the mass of the isotope.

Explanation:

The reason for the difference seen between the atomic mass provided in the periodic table and the atomic mass of each element is that most naturally occurring elements have more than one isotope (isotopes are atoms that have the same atomic number but different mass numbers). This means that when we measure the atomic mass of an element, we must generally settle for the average mass of the naturally occurring mixture of isotopes.

¹⁹F is the only stable isotope of fluorine, and its abundance is 100%. Therefore, its atomic mass is identical to that of the isotope.

On the other hand, chlorine has two stable isotopes ³⁵Cl (75.77%) and ³⁷Cl (24.23%). The atomic mass of  ³⁵Cl has been determined to be 34.96885 amu, and the atomic mass of ³⁷Cl has been determined to be 36.96590 amu. Thus, the average atomic mass  of chlorine can be calculated as follows:

average atomic mass  of natural chlorine = (0.7577)×(34.96885 amu) + (0.2423)×(36.96590 amu)  = 35.45 amu

Note that in calculations involving percentages, we need to convert percentages to  fractions.

This extremely high temperature indicates that under normal conditions, you do not need to worry about your car tire bursting from overheating as it is unlikely to reach such extreme temperatures.

To determine the temperature at which the tire will burst, we can use the ideal gas law equation:

PV = nRT

Where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.

Rearranging the equation to solve for temperature, we have:

T = PV / (nR)

Given that the pressure threshold for bursting is 1.4 x 10^3 kPa, the volume is 30 L, and the number of moles of air is 2.5 mol, we can substitute these values along with the ideal gas constant R = 8.314 J/(mol K) into the equation.

T = (1.4 x 10^3 kPa) * (30 L) / (2.5 mol * 8.314 J/(mol K))

Converting kPa to Pa and L to m^3, and simplifying the equation, we find:

T ≈ 20,993 K

This extremely high temperature indicates that under normal conditions, you do not need to worry about your car tire bursting from overheating as it is unlikely to reach such extreme temperatures.

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Answer:

Explanation:

aluminum

Answer: The aluminum ion

Explanation:

If there are 4 moles of O2, 0.6667 moles of the C6H12O6 are present.

If there are 4 moles of oxygen present. In that case, we can use the balanced chemical equation for glucose combustion to calculate the number of moles of glucose required to react with it.

According to the equation, one mole of glucose reacts with six moles of oxygen to produce six moles of carbon dioxide and six moles of water. The number of moles of glucose required to react with it is calculated by dividing the number of moles of oxygen by six.

So, if 4 moles of oxygen are present, 0.6667 moles of glucose must react with it.

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Answer:

.. ..

:O = C - Cl:

.. | ..

:Cl:

..

Anything around us that can be physically seen and touched are matter. Matter can be solid, liquid or gas. To solve this question we need to know the all properties of liquid so option D is correct option.

Matter is a substance that has some mass and can occupy some volume. Matter that is given is liquid which has property that it occupies the volume of container in which it is kept.

There is a law called conservation of mass, mass can never be destroyed. To change and color of liquid  we need to heat up the liquid and that we are not doing over here.

Thus option D is correct option.

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Answer:

An unknown metal between 10-30 g is transferred to a test tube, place the tube in water that is boiling for ten minutes until it reaches a thermal equilibrium.

Explanation:

The combined gas law equation is:

(P1 * V1) / (T1) = (P2 * V2) / (T2)

The volume of the gas at 30 °C is approximately 760.67 mL.

To determine the volume of the gas at 30 °C, we can use the combined gas law equation, which relates the initial and final conditions of temperature and volume for a gas.

The combined gas law equation is:

(P1 * V1) / (T1) = (P2 * V2) / (T2)

Where:

P1 and P2 are the initial and final pressures, respectively

V1 and V2 are the initial and final volumes, respectively

T1 and T2 are the initial and final temperatures in Kelvin, respectively

We need to convert the temperatures from Celsius to Kelvin by adding 273.15 to each value.

Given:

V1 = 550 mL

T1 = -55 °C = 218.15 K

T2 = 30 °C = 303.15 K

Assuming the pressure remains constant, we can rearrange the equation to solve for V2:

V2 = (P1 * V1 * T2) / (P2 * T1)

Since the pressure is not specified in the problem, we can assume it remains constant, allowing us to cancel out the pressure terms. Thus, the final equation becomes:

V2 = (V1 * T2) / T1

Plugging in the given values:

V2 = (550 mL * 303.15 K) / 218.15 K

Simplifying the calculation, we find:

V2 ≈ 760.67 mL

Therefore, the volume of the gas at 30 °C is approximately 760.67 mL.

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Sedimentation, filtration, and coagulation are the treatments that will help remove contaminants from minerals or from the pipes carrying water from a source.

Sedimentation is a process in which suspended particles settle out of water. It is one of the most basic techniques for removing particles from water. As particles settle, they become trapped in the bottom of a container or settle to the ground in an outdoor setting

Filtration is a method of removing particles from a fluid. It is a physical or chemical separation method that separates solids from fluids (liquids or gases) by adding a medium through which only the fluid can pass.

Coagulation is the process of using chemicals to remove contaminants from water. By creating a chemical reaction, coagulation destabilizes particles and causes them to clump together. This helps to remove the contaminants from the water.

Disinfection is the process of eliminating or destroying pathogens that cause infection. Disinfection eliminates harmful microorganisms by destroying or inactivating them. The disinfectant is a chemical or physical agent that is used to destroy or inactivate harmful microorganisms.

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Answer:

Magnesium chloride/Molar mass

95.211 g/mol

Explanation:

The empirical formula for a compound composed of 9.93% carbon, 58.6% chlorine, and 31.4% fluorine is CCl₂F₂.

To write the empirical formula, let us assume that total mass of the compound is 100 g, then-

Mass of carbon = 9.93 g

Mass of chlorine = 58.6 g

Mass of fluorine = 31.4 g

We know that,

Molar mass of Carbon = 12.0 g/mol

Molar mass of Chlorine = 35.5 g/mol

Molar mass of Fluorine = 18.9 g/mol

Now, we will calculate the number of moles of each using the formula -

Number of moles = Given mass

                                 Molar mass

Moles of Carbon =   9.93 g     = 0.82 mol

                               12.01 g/mol

Moles of Chlorine =    58.6 g     = 1.65 mol

                                 35.5 g/mol

Moles of fluorine =    31.4 g     = 1.66 mol

                                18.9 g/mol

Now, divide each value with the smallest amount of mole we got,

carbon = 0.82 = 1

               0.82

chlorine = 1.65 =  2

                 0.82

fluorine = 1.66 = 2

                0.82

Therefore, the empirical formula of the compound can be written as - CCl₂F₂

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The amount of volume of KOH solution that should be added to make 500mL of a 0.300M solution is 200mL.

The volume of a solution given the concentration can be calculated using the following expression;

CaVa = CbVb

Where;

According to this question, we are to calculate how many mL of a 0.75 M OH solution that should be added to a 500 mL flask to make 500 mL of a 0.300 M KOH solution.

0.75 × Va = 500 × 0.3

0.75Va = 150

Va = 150/0.75

Va = 200mL

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Answer:

0.00370 g

Explanation:

From the given information:

To determine the amount of acid remaining using the formula:\(\dfrac{(final \ mass \ of \ solute)_{water}}{(initial \ mass \ of \ solute )_{water}} = (\dfrac{v_2}{v_1+v_2\times k_d})^n\)

where;

v_1 = volume of organic solvent = 20-mL

n = numbers of extractions = 4

v_2 = actual volume of water = 100-mL

k_d = distribution coefficient = 10

∴

\(\dfrac{(final \ mass \ of \ solute)_{water}}{0.30 \ g} = (\dfrac{100 \ ml}{100 \ ml +20 \ ml \times 10})^4\)

\(\dfrac{(final \ mass \ of \ solute)_{water}}{0.30 \ g} = (\dfrac{100 \ ml}{100 \ ml +200 \ ml})^4\)

\(\dfrac{(final \ mass \ of \ solute)_{water}}{0.30 \ g} = (\dfrac{1}{3})^4\)

\(\dfrac{(final \ mass \ of \ solute)_{water}}{0.30 \ g} = 0.012345\)

Thus, the final amount of acid left in the water = 0.012345 * 0.30

= 0.00370 g

(E, E)-3,5-octadiene, molecular formula is C8H14, molecular weight is 110.20,(3E,5E)-octa-3,5-diene is its IUPAC name.

What is IUPAC?

The International Union of Pure and Applied Chemistry (IUPAC) is a global federation of National Adhering Organizations dedicated to the progress of the chemical sciences, particularly through the creation of nomenclature and terminology. It is an International Science Council member (ISC).

What is the Molecular formula?

A molecule is made up of two or more atoms that have joined together chemically. A molecular formula is the chemical representation of a molecular compound that lists the types and quantities of atoms that make up each molecule.

Hence, the structure of the compound (E, E)-3,5-octadiene is in the image attached. The image is from Pubchem, National library of medicine (NCBI).

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The plane of the Moon's orbit around the Earth is tilted by 5° with respect to the plane of the Earth's orbit around the Sun, the ecliptic. This tilt prevents an eclipse from occurring at every new and full moon. In a lunar eclipse, the observer watches the Earth's shadow fall on the Moon.

Answer:

Because there is no light in space so there is no shadow

The following balanced chemical equation may be used to describe the interaction between aluminum (Al) and calcium nitrate (Ca(NO₃)₂):

2 Al + 3 Ca(NO₃)₂ → 2 Al(NO₃)3 + 3 Ca

Reactants are the chemicals that begin a chemical reaction, while products are the compounds that are created as a result of the reaction.

The substances that initiate a chemical reaction. Products are the substances that are created during the reaction. Compounds or elements can act as reactants and products.

Aluminium and calcium nitrate interact in this reaction to form aluminium nitrate (Al(NO₃)₃) and calcium (Ca), which are the end products.

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The cell would burst as water moved into the cell along a concentration gradient from high to low.

If a salt-filled cell is placed in fresh water, osmosis will occur. Osmosis is the diffusion of water molecules from an area of high concentration to an area of low concentration through a semi-permeable membrane. In this case, the semi-permeable membrane is the cell membrane that surrounds the salt-filled cell.

Since the concentration of salt inside the cell is higher than the concentration of salt in the fresh water, water molecules will move from the fresh water into the cell in an attempt to balance the concentration of salt on both sides of the membrane. This results in an increase in the volume of the cell, which can cause the cell to swell or even burst.

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Answer:

Answer: The two types of fibres obtained from the fleece of a sheep are beard hair, which are coarse and fine, and soft under hair, which grow near the skin. The under hair are used to make wool.

Explanation:

mark brainly please!

(I didn't copy the person above me! I just realized we had the same answer.)

Answer:

Explanation:

Here, we want to select 3 statements that are true about metalloids

Metalloids are the middle ground between metals and non-metals

They are not completely metals and also are not completely non-metals. They are in between the two kinds of elements

The correct choice of answers are the following:

a) They are somewhat reactive

b) This is incorrect because they are usually not malleable. An example is silicon

c) This is correct. They are popular for making semi-conductors

d) This is also correct. They are the bridge between metallic and non-metallic elements

Answer:

Why does a beaker disappear in oil?

If you submerge regular glass in vegetable oil, the light is refracted between the oil and the glass surface, allowing you to see the glass through the oil. ... The Pyrex® glass has the same angle of refraction as the vegetable oil, so the light bends at the same angle. As a result, the Pyrex® glass seems invisible.

Explanation:

Answer: im not sure if this is the best answer but i wrote, "This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."

Explanation: hope this helps.

This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."

Thus, For persons with autism, life can be incredibly stressful at times, and their behaviour may be an indication of their utter exasperation or suffering in reaction to a variety of pressures.

Some people struggle with the idea of time and sequencing, thus this can involve onerous tasks, meeting new people, experiencing unpleasant sensory stimuli, a change in routine, switching activities, or having to wait for anything.

The individual may have realized how effective their actions could be in influencing their environment. A behaviour that was initially a reaction to physical discomfort or frustration may later develop into a strategy for evading a request or getting rid of an uncomfortable circumstance.

Thus, This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."

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The question is Incomplete, the complete question is:

Briefly describe the physical behavior?

What is the exploration about?

What are you trying to discover?

Relate to any previous work.

Use new vocabulary words, if you can.

In the exploration, I was a bird trying to eat bugs placed in different backgrounds. Each bug was adifferent color, and the color either matched or stood out against the background. What I wastrying to discover was how creatures adapted to their environment and if blending in with theirenvironment helped them or hindered them. I discovered that yes, blending in with theenvironment helps creatures survive.

By using the ideal gas law and Avogadro's number, we find that there are approximately 6.72 × 10^22 molecules of CO2 in 2.5 L at STP.

To determine the number of molecules of CO2 in 2.5 L at STP (Standard Temperature and Pressure), we can use the ideal gas law and Avogadro's number.

Avogadro's number (N_A) is a fundamental constant representing the number of particles (atoms, molecules, ions) in one mole of substance. Its value is approximately 6.022 × 10^23 particles/mol.

STP conditions are defined as a temperature of 273.15 K (0 °C) and a pressure of 1 atmosphere (1 atm).

First, we need to convert the volume from liters to moles of CO2. To do this, we use the ideal gas law equation:

PV = nRT,

where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.

Since we have STP conditions, we can substitute the values:

(1 atm) × (2.5 L) = n × (0.0821 L·atm/(mol·K)) × (273.15 K).

Simplifying the equation:

2.5 = n × 22.4149.

Solving for n (the number of moles):

n = 2.5 / 22.4149 ≈ 0.1116 moles.

Next, we can calculate the number of molecules using Avogadro's number:

Number of molecules = n × N_A.

Number of molecules = 0.1116 moles × (6.022 × 10^23 particles/mol).

Number of molecules ≈ 6.72 × 10^22 molecules.

Therefore, there are approximately 6.72 × 10^22 molecules of CO2 in 2.5 L at STP.

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Answer:

It is important to record the crime scene in order to view how it was originally found so when items are removed, it can still be investigated and viewed.

Explanation: