I need help please..

If 105.5mg sample of a white substance, suspected of being

cocaine (C17H21NO4), forms 2.79.3mg of CO2 and 66.46mg of

water on combustion, then the white solid is cocaine.

A Combustion reaction is defined as the chemical reaction which is generally a fuel that undergoes an oxidation by the reaction by the help of an oxidizing agent, which further results in the emission of energy.

Thus, we concluded that the white solid is cocaine if If 105.5mg sample of a white substance, suspected of being

cocaine (C17H21NO4), forms 2.79.3mg of CO2 and 66.46mg of water on combustion.

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Gold and copper are both metallic conductors that have resistivity in the range of 2 x 10-².

The semiconductor silicon has a resistivity of 6.4 x 102m.

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The speed of an electron expelled from a surface when light with a wavelength of 690.0 nm is delivered. A wavelength of 795 nm has sufficient energy to eject electrons is v = 2.886 × 10⁵ m/s.

The wavelength, which will also apply to troughs, is the separation between two wave crests. The frequency is measured in cycles per second (Hz), which is the quantity of vibrations that cross a specific area in a second (Hertz). In this article, the relationship between wavelength and frequency is covered.

hf = Φ + KE

Φ = Work function is energy required to remove an electron in (J)

h = Planck’s constant = 6.626 x 10⁻³⁴ J • s

f = threshold frequency or higher

KE = maximum kinetic energy of emitted electrons (J)

Electron mass is 9.109 x 10⁻³¹ kg kg and the speed of light is 2.998 x 10⁸ m/s

The energy of a photon of 795 nm light will give the work function Φ.

λ = 795 nm = 7.95 x 10⁻⁹ m

E = (hc/λ) = 2.499 x 10⁻¹⁹ J

Find the energy of a photon with wavelength λ = 336.0 nm = 3.360 x 10⁻⁷ m

m = 9.1 * 10⁻³¹ kg

1/2mv² = hc (1/690×10⁻⁹ - 1/795 × 10⁻⁹)

1/2mv² = 6.62 × 10⁻³⁴ × 2.998 ×10⁸ (10⁹/690 - 0.001258 × 10⁹⁹)

1/2mv² = 19.874 × 10⁻²⁶ (0.001449 × 10⁻⁹ - 0.001258 × 10⁻⁹)

1/2mv² = 19.847 × 10⁻²⁶ (1.44 * 10⁻⁶ - 1.258 × 10⁶)

1/2mv² = 19.847 × 10⁻²⁰ (1.449 - 1.258)

1/2mv² = 19.847 × 10⁻²⁰ × 0.191

1/2mv² = 3.791 × 10⁻²⁰

v² = 3.791 × 10⁻²⁰/m

v² = 7.582 × 10⁻²⁰/9.1 × 10⁻³¹

v² = 0.8332 × 10¹¹

v² = √8.332 × 10¹⁰

v = 2.886 × 10⁵ m/s.

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Gamma ray have the highest frequency.

Gamma ray has the shortest wave length. it has the highest energy and highest frequency. Gamma Radiation region has the highest frequency.

Electromagnetic spectrum is the range of frequencies of the EM radiations and their wavelengths.  

Frequency is the number of waves that pass a point at unit time. It can be also defines as the number of cycles or vibrations .Its Formula is,

                                        f=1/T

          were f= frequency,

                   T= time period.

Time period is the duration of time in which an activity occurs.

In Gamma ray their wavelengths are shorter that the nucleus of the atom, because of this they have high frequencies. Their frequencies are greater than 1019Hz.

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The density of the given gold bar is 9.52 .

The density of gold metal used for jewellery is 19.32g/cm³

Given gold bar has mass of 10 grams and has volume of 1.05.

Density = mass /volume ⇒D =10/ 1.05= 9.52 g/cm³

so, the gold bar king has is not pure gold.

The acid test for gold is by rubbing  the gold-colored item on black stone, which will leave an easily visible mark. The mark is then tested by applying nitric acid, which dissolves the mark of item that is not gold. If the mark remains same, it is tested by applying aqua regia (nitric acid and hydrochloric acid).

In a nitric acid test, a jeweler places a few drops of the acid on the piece of item and watches for the reaction. With copper, the reaction causes the liquid to turn green, give off fumes, and  bubble. This response is called a hard cupric reaction and indicates that the item is not real gold

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Answer:

Explanation:

5568 is   c

Answer:

the carbon fiber hood on the drift car guided eyes to the car and the driver in the seat blankly stairs

The molar extinction coefficient of the given dye will be calculated as 10,750 M⁻¹cm⁻¹ which is done by the formula given by Beer Lambert's Law.

According to the Beer-Lambert law, there is a linear relationship between a solution's concentration and absorbance, making it possible to determine a solution's concentration by observing its absorbance.

Beer Lambert's -equation is as follows:

A=ϵbc

where:

A is absorption

ϵ represents the molar extinction coefficient.

b is the length of the path (in cm)

c here refers to molar concentration

The data provided for the stock solution can be used to compute the molar extinction coefficient:

A= ∈bc

0.43= ∈(1cm) ( 0.000040)

∈=10,750 M⁻¹cm⁻¹

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The molarity of the given solution will be 0.434 M  . Since the concentration is given in percentage in mass/volume  form, the molarity of the solution will be calculated as follows:

Here,

Concentration= 4.61% m/v

Molecular mas of xylene= 106.2g/mol

Moecular mass of toulene = 92.30g/mol

Molarity is defined to be as moles of solute present per liter of solution.  Here  we are dealing with two liquids, the one having greater amount will be taken  as the solvent and the one having lower amount will be taken as the solute

4.61% m/v = 4.61 g xylene/100 ml toulene

= 4.61 g xylene/L

Now Converting this to moles / L we will get:

46.1 g xylene  x 1

mol/106.2 g = 0.434 moles xylene per L of toulene

Molarity (M) = No of moles of solute  / Volume of solute( L)

= 0.434 moles / 1 L

= 0.434 M

So, the concentration of the given solution in molarity will be equal 0.434M

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Answer:

2.6187E24 same as 2.6187 × 10^24

Explanation:

we must use 1 conversion fact 6.02E23

1. Convert to Atoms of P from Moles of P

4.35 × 6.02E23 = 2.6187E24

Please let me know if i need to further eloborate :)

0.1 ml of  volumetric pipette is required to prepare 250 ml of copper sulfate solution.

Size of pipettes is determined by a wide range of factors such as physical properties of liquid,precision and accuracy of results to be obtained.

For knowing what size of pipette is to be used for making 0.015 M copper sulfate solution ,first the mass of copper sulfate to be used in making the solution is to be determined.Substituting the known parameters in the molarity formula mass of copper sulfate to be used is determined.

M=mass/molar mass×1/volume of solution in liters

mass=0.015×159.60×0.25=0.5985 g

Now to find out the volume of pipette to be used,using the density formula the volume of pipette can be obtained.

volume=0.5985/3.6=0.1

Therefore,0.1 ml of pipette is to be used for preparing 250 ml of 0.015 M copper sulfate solution.

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The correct answer is cation Ni +2 and anion S 2-.

Nickel sulfide

It is discovered that the bonding in NiS is remarkably similar to that in NiO, with a covalent component resulting from bonds between the Ni 3d and the S 3p atom and an ionic contribution resulting from the donation of the Ni 4s electron to the S atom.

With heated concentrated nitric acid or aqua regia, NiS can be easily reactively dissolved, which is followed by sulphur precipitation.

F belongs to Group 7A, while Ni is in Group 5A. (EN: N=3.0, F=4.0) The NF3 molecule and each N-F bond are both polar. F possesses a partial positive charge in the N-F bond. The NF3 molecule and each N-F bond are both non-polar.

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All life on Earth depends on the atom carbon. All plant and animal life involves the ingestion and expulsion of carbon, whether it be for the purpose of producing food or as part of respiration. Carbon is always moving from one location to another.

Explain how carbon can move through the organisms in that ecosystem.

Carbon moves from photosynthetic plants to other consumers in the kelp forest. Carbon is transferred from bacteria to other consumers when at hydrothermal vents.

Ecosystem of the kelp forest:

Water-heating vent Ecosystem:

These bacteria coexist symbiotically with the primary consumer.

On the principal consumer, the other consumers feed.

As a result, we can infer that carbon is transferred from photosynthetic plants to other consumers in kelp forests. Carbon is transferred from bacteria to other consumers when at hydrothermal vents.

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Answer:

1 helium has 4 atomic mass and 1 sulfur has 32 atomic mas.

Answer:

104.9 g

Explanation:

If you add a piece of silver to water which increases the volume of the water from 20 mL to 30 mL, according to water displacement, the piece of silver must be 10 mL (30 mL - 20 mL = 10 mL).

You can find the mass by multiplying the volume of silver by the density. The denisty exists as a ratio comparing the mass (g) of silver per every 1 mL. It is important to arrange the ratio in a way that allows for the cancellation of units (mL should be in the denominator).

  10 mL             10.49 g
--------------  x  -----------------  =  104.9 g
                           1 mL

can't give an answer to your question if there isn't a picture or being specific in the question.

Answer: 2 Out of 4

Explanation:

Bc my mom told me

Answer:

d) solar panels and solar cells

The number of cubic centimeters (cm³) in 8.14 yd³ is 6.22×10⁶ cm³

Cubic yard (yd³) can be converted to cubic centimeters (cm³) by using the folloing scale

1 yd³ = 764555 cm³

With the above conversion scale, we can obtain the number of cubic centimeters (cm³) in 8.14 yd³. Details below

From the question given above, filling data were obtained:

1 yd³ = 764555 cm³

Therefore,

8.14 yd³ = (8.14 yd³ × 764555 cm³) / 1 yd³

8.14 yd³ = 6.22×10⁶ cm³

From the calculation made above, we can conclude that there are 6.22×10⁶ cubic centimeters in 8.14 yd³

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Answer:

pls check your question again i think you question is wrong.

Answer

0.6 km/min2

Explanation:

Answer:

?????????

Explanation:

When determining the significance of digits in a number, the general rule is as follows:

1. Non-zero digits are always considered significant.

2. Leading zeros (zeros to the left of the first non-zero digit) are not considered significant.

3. Captive zeros (zeros between non-zero digits) are considered significant.

4. Trailing zeros (zeros to the right of the last non-zero digit) may or may not be significant, depending on whether they serve as placeholders.

In the number 0.04600, we can label each digit as follows:

0.04600

The first zero is a leading zero and is not considered significant.

The digit 0 after the decimal point is considered significant as it is a captive zero.

The digits 4 and 6 are non-zero digits and are considered significant.

The last two zeros are trailing zeros, and their significance depends on whether they serve as placeholders.

If the zeros in 0.04600 are intended to indicate the precision of the measurement or represent significant figures, then the trailing zeros are significant. In this case, all the digits in the number (0.04600) are significant.

However, if the zeros in 0.04600 are not intended to convey the precision or significant figures, and they are just placeholders, then only the first three digits (0.046) are significant, and the trailing zeros are not significant.

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0.6066 moles of water are produced by complete ammoxidation of 145 g of o-xylene.

Number of moles are calculated by dividing the mass by the molar mass of the substance.In the reaction between o-xylene ,ammonia and oxygen pthalonitrile  is produced.

Here, the number of o-xylene is calculated by the above mentioned formula which is 1.365 moles.Then, as per stoichiometry and balanced chemical equation ,

1.365 moles of o-xylene×8 moles of water/1 mole of xylene ×18 g water

=0.6066 moles

Thus,0.6066 moles of water are produced from 145 g of o-xylene.

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Cells cannot be as large as a cube because the surface area to volume ratio decreases as cell size increases.

What are cells?

The cell is the fundamental structural and functional unit of all living things. Every cell is made up of cytoplasm surrounded by a membrane that includes several biomolecules such as proteins and nucleic acids.

Cells cannot be as large as a cube because the surface area to volume ratio decreases as cell size increases. As a result, if the cell develops beyond a certain point, the cell contents will be unable to cross the cellular membrane as quickly in order to accommodate the increased cellular volume.

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a. (i) The bonding in iron is not covalent.

    (ii) NaCl i.e. sodium chloride do not have covalent bond.

    (v) Argon is an inert gas do not form molecules by any sort of bonding.

b. A substance XY, formed from two different elements, boils at -33 °C is XY likely to be covalent. Since its boiling point is much below zero degree Celsius, the binary compound is a gas at room temperature.

Metallic bonding is a type of bonding that exists in iron. Iron is a metal, and all metals have a specific kind of connection that isn't covalent or ionic called metallic bonding. The outer shells of neighboring atoms overlap during metallic bonding, and the outer shell electrons are free to move about the lattice.

The hydrogen and oxygen atoms in water share their electrons hence covalent bonding.

Sodium Chloride (NaCl) is a pure ionic compound and not a covalent compound. The two atoms transfer their electrons to form ions, Na+ and Cl-.

The two oxygen atoms share two pairs of electrons, so two covalent bonds hold the oxygen molecule together.

Argon is an inert gas do not form molecules by any sort of bonding.

For the substance XY, its boiling point is beyond zero which happens to be present in case of gases thus it is a covalent substance.

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Sodium bicarbonate is a white crystalline powder. NaHCO3 + H+ (from tartaric acid)→ CO2 + H2O + Sodium tartrate.

Sodium bicarbonate is a white crystalline compound. It is alkaline. Sodium bicarbonate is a compound made up of sodium, hydrogen, carbon, and oxygen.

Sodium bicarbonate can be used as an antacid. It can also be used in making ear drops.  It is used in cleaning the mouth and teeth because of its  antibacterial properties.

The chemical reaction when sodium bicarbonate reacts with tartaric acid is given below:

NaHCO3 + H+ (from tartaric acid)→ CO2 + H2O + Sodium tartrate.

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If the surface temperature on Mercury has been measured to be 603 K, this temperature is equivalent to 329.84°C (degrees Celsius).

Temperature is the measure of cold or heat, often measurable with a thermometer.

Kelvin, which is denoted by K, is the International System of Units (S.I unit) or the base unit of thermodynamic temperature.

However, Kelvin can be converted to degree Celsius as follows:

K = 273.16 + °C

According to this question, the surface temperature on Mercury has been measured to be 603 K. This temperature can be converted to °C as follows:

603K = 273.16K + °C

°C = 603 - 273.16

°C = 329.84°C

Therefore, if the surface temperature on Mercury has been measured to be 603 K, this temperature is equivalent to 329.84°C (degrees Celsius).

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Three quantum numbers were derived from Schrodinger wave equation.

Quantum numbers can be obtained while solving Schrodinger wave equation by the boundary conditions which can be applied while solving the equation in order to obtain solution which fits all the physical conditions.

Out of the four quantum numbers  the principal quantum number,azimuthal quantum number and magnetic quantum number can be obtained from solving  Schrodinger wave equation.

The only quantum number which cannot be  obtained from solving the  Schrodinger wave equation is spin quantum number,because it is related spin of the electrons which is explained by the Pauli's exclusion principle.

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The substance is pure matter, it is either an element or a compound. If a substance can be divided into its component elements matter, it is a compound.

If a substance is not chemically pure, it is either a homogeneous mixture or a heterogeneous mixture.

If the composition remains the same throughout, the combination is homogeneous.

The two major categories into which matter can be categorised are pure substances and mixtures. Pure substances and mixtures are the two major categories into which matter may be divided.

A sort of matter known as a pure substance has qualities that are continuous throughout the sample and a stable composition that makes it the same everywhere. A matter is a substance made up of two or more different components.

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