which activity is an example of a chemical change ?
​

Answer:

f = 4.6 × 10¹⁴ Hz

Explanation:

Given data:

Wavelength  of light = 6.50x10^-7m

Speed of light = 3.00 x 10^8 m/s

Frequency of light = ?

Solution:

Formula:

Speed of radiation = frequency × wavelength

by putting values,

3×10⁸ m/s  =  f × 6.50x10^-7m

f  =  3×10⁸ m/s   /  6.50x10^-7m

f  =  0.46 × 10¹⁵ s⁻¹

f = 0.46 × 10¹⁵ Hz

f = 4.6 × 10¹⁴ Hz

Answer:

See explanation and image attached

Explanation:

Now, we have chosen the alkene 1-propene in our example.

In the first reaction of  1-propene  with HBr, the reaction proceeds by ionic mechanism leading to the formation of 2-bromo propane.

In the second reaction of  1-propene  with the bromine molecule, the first step is the formation of the brominium cation which is a cyclic intermidiate followed by the addition of Br^- yielding the 1,2- dibromopropane product

Answer:

132.14 g/mol

Explanation:

Answer:

0.00182 cm

Explanation:

Area of the aluminum foil = 22.86 cm ×22.86 cm = 522.58 cm^2

Density = mass/area × thickness

Density × area × thickness = mass

Thickness = mass/ Density × area

Thickness = 2.568 g/2.70 g/cm^3 × 522.58 cm^2

Thickness= 0.00182 cm

Answer:

0.64 in trial 2

Explanation:

Answer: As a consequence, chemical equations must be balanced, meaning that the number and kinds of atoms must be the same on both sides of the reaction arrow. The numbers placed in front of formulas to balance equations are called coefficients, and they multiply all the atoms in a formula.

Answer:

One week.

Explanation:

I would think one month because on weather websites you can see a month of weather. But the closer the day your looking at the prediction will be more accurate.

The most accurate range of data for weather forecasting is: A. one week.

Weather can be defined as the average atmospheric conditions of a particular area (region) over a short period of time.

Some examples of the elements of weather include the following:

In meteorology, the most common forecasted element of weather is temperature (degree of hotness or coldness) and it usually done a weekly basis such as one week.

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Answer:

9717.246 J

Explanation:

From the question given above, the following data were obtained:

Mass (m) of water = 40.5 g

Initial temperature (T₁) = 15.6 °C

Final temperature (T₂) = 73 °C

Specific heat capacity (C) of water = 4.18 J/gºC

Heat (Q) =.?

Next, we shall determine the change in the temperature of water. This can be obtained as follow:

Initial temperature (T₁) = 15.6 °C

Final temperature (T₂) = 73 °C

Change in temperature (ΔT) =?

ΔT = T₂ – T₁

ΔT = 73 – 15.6

ΔT = 57.4 °C

Finally, we shall determine the heat energy required. This can be obtained as follow:

Mass (m) of water = 40.5 g

Specific heat capacity (C) of water = 4.18 J/gºC

Change in temperature (ΔT) = 57.4 °C

Heat (Q) =.?

Q = MCΔT

Q = 40.5 × 4.18 × 57.4

Q = 9717.246 J

Thus, the heat energy required is 9717.246 J

Answer: C- one should have high electron affinity and the other low ionization energy.

Explanation:

Ionization energy is the energy required to remove the electron from an isolated gaseous atom.

Electron affinity is the tendency of an isolated atom to attrcat the electrons towards itsellf.

An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element or the metal and it can donate electron easily if it has low ionization energy.

The element which accepts the electrons is known as electronegative element or non metal and it can easily accept the electron if it has high electron affinity.

Answer: [tex]CsF[/tex] > [tex]SrF_2[/tex] >  [tex]OF_2[/tex]  > [tex]F_2[/tex]

Explanation:

The percent ionic character is used to determine if a bond is more ionic or covalent. More is the percent ionic character, the more ionic the molecule is. If the electronegativity difference between two elements is higher than 1.7 it will be considered as ionic.

The electronegativity difference for CsF is (3.98-0.79) = 3.19

The electronegativity difference for [tex]OF_2[/tex] is = (3.98-3.44) = 0.54

The electronegativity difference for [tex]SrF_2[/tex] is (3.98-0.95) = 3.0

The electronegativity difference for [tex]F_2[/tex] is  0.

Thus decreasing order of  ionic character of the bonds is CsF >  [tex]SrF_2[/tex] >  [tex]OF_2[/tex]  > [tex]F_2[/tex]

Answer:

an atom is the smallest part of an element that has the properties of that element

it can't be broken further into smaller substances

an element is the simplest chemical

it consists of one type of atoms

so you can consider atoms as the building block of an element

Answer:

Mass = 18.29 g  

Explanation:

Given data:

Mass of beryllium needed = ?

Mass of nitrogen = 18.9 g

Solution:

Chemical equation:

3Be + N₂    →    Be₃N₂

Number of moles of nitrogen:

Number of moles = mass/molar mass

Molar mass of nitrogen = 28 g/mol

Number of moles = 18.9 g/ 28 g/mol

Number of moles = 0.675 mol

Now we will compare the moles of nitrogen and Be.

                       N₂        :       Be        

                        1          :       3

                   0.675       :      3/1×0.675 = 2.03 mol

Mass of Be:

Mass = number of moles × molar mass

Mass = 2.03 mol ×   9.01 g/mol

Mass = 18.29 g  

Answer:

One could be What kind of insulator do you use in the winter?

Explanation:

Answer:

Explanation:

Two or more compounds are said to be isomers if they have the same molecular formula but different structures.

Isomers that have the same molecular formula but different connectivity are largely regarded as constitutional isomers.

From below, we can see the different constitutional isomers of C2H6O2.

(a)

[tex]\mathbf{CH_3 - O - O - CH_3}[/tex]

(b)

CH₃ - CH₂ - O - O - H  

(c)

   [tex]OH\ \ \ \ \ \ \ \ \ \ \ OH[/tex]

     |                |

 CH₂    --     CH₂

(d)

           OH

            |

CH₃ -- CH

            |

          OH

(e)

[tex]\mathbf{CH_3- O - CH_2-OH}[/tex]

Answer:

Estoy deprimido y odio la vida. Así que sí

Answer:

cup...................

Taking into account the definition of density, the mass of the sample of oil with a volume of 10 cm³ and a density of 0.8 [tex]\frac{g}{cm^{3} }[/tex]  is 8 grams.

Density is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space.

In other words, density is a quantity that allows us to measure the amount of mass in a certain volume of a substance.

Then, the expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:

[tex]density=\frac{mass}{volume}[/tex]

From this expression it can be deduced that density is inversely proportional to volume: the smaller the volume occupied by a given mass, the higher the density.

In this case, you know that:

Replacing in the definition of density:

[tex]0.8 \frac{g}{cm^{3} } =\frac{mass}{10 cm^{3} }[/tex]

Solving:

mass=  0.8 [tex]\frac{g}{cm^{3} }[/tex] × 10 cm³

mass= 8 g

In summary, the mass of the sample of oil with a volume of 10 cm³ and a density of 0.8 [tex]\frac{g}{cm^{3} }[/tex]  is 8 grams.

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Answer:

When converting from liters to moles or moles to liters, you will use the equality 1 mole=22.4 L for a gas at STP.

If you have moles and want to convert to (Volume) liters, 1 mole = 22.4 L is the conversion factor that can be used.

The area that any three-dimensional solid occupies is known as its volume. These solids can take the form of a cube, cuboid, cone, cylinder, or sphere. Various forms have various volumes. We have studied the several solids and forms that are specified in three dimensions, such as cubes, cuboids, cylinders, cones, etc., in 3D geometry. We will discover how we can determine the volume for each of these shapes. One mole of any gas have 22.4 L at STP.

1 mole = 22.4 L

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Answer:

False

Explanation:

Mixtures are impure substances.

There are two types of mixtures based on the number of coexisting phases.

Homogeneous mixtures have their constituents existing in one single phase. The components are evenly spaced.

Heterogeneous mixtures have their constituents existing in at least two different phases. Therefore, they are unevenly spaced due to the phases present within the mixture.

Answer:

I think its C

Explanation:

but don't trust me 2 much

The environment provides a vast array of materials and services that people use to live. Often these resources have competing uses and values.  In order to conserve environment change our resource use habits. The correct option is C.

An environmental resource is any material, service, or information from the environment that is valuable to society. This can refer to anything that people find useful in their environs, or surroundings. Food from plants and animals, wood for cooking, heating, and building, metals, coal , and oil are all environmental resources.

Clean land, air, and water are environmental resources, as are the abilities of land, air, and water to absorb society's waste products. Heat from the sun, transportation and recreation in lakes, rivers, and oceans, a beautiful view, or the discovery of a new species are all environmental resources.

Thus the correct option is C.

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Answer:

9 . this was not able the first one. it has to go on, I will not sure about

The volume of the gas : V = 13.243 L

Given

n = 0.25 mole

P = 0.5 atm

T = 50 + 273 = 323 K

Required

The volume

Solution

Ideal gas law

PV=nRT

R = gas constant = 0.082 L.atm/mol K

V = nRT/P

Input the value :

V=0.25 x 0.082 x 323 / 0.5

V = 13.243 L

Answer:

To calculate the pressure when temperature and volume has changed, we use the equation given by combined gas law. The equation follows:

\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}

T

1

P

1

V

1

=

T

2

P

2

V

2

where,

P_1,V_1\text{ and }T_1P

1

,V

1

and T

1

are the initial pressure, volume and temperature of the gas

P_2,V_2\text{ and }T_2P

2

,V

2

and T

2

are the final pressure, volume and temperature of the gas

We are given:

\begin{gathered}P_1=760mmHg\\V_1=175L\\T_1=15^oC=[15+273]K=288K\\P_2=640mmHg\\V_2=198L\\T_2=?K\end{gathered}

P

1

=760mmHg

V

1

=175L

T

1

=15

o

C=[15+273]K=288K

P

2

=640mmHg

V

2

=198L

T

2

=?K

Putting values in above equation, we get:

\begin{gathered}\frac{760mmHg\times 175L}{288K}=\frac{640mmHg\times 198L}{T_2}\\\\T_2=274K\end{gathered}

288K

760mmHg×175L

=

T

2

640mmHg×198L

T

2

=274K

Hence, the temperature when the volume and pressure has changed is 274 K

Answer:

electron transport 11 is the correct answer

Answer:

Change is happening all around us all of the time. Just as chemists have classified elements and compounds, they have also classified types of changes. Changes are classified as either physical or chemical changes. Chemists learn a lot about the nature of matter by studying the changes that matter can undergo. Chemists make a distinction between two different types of changes that they study—physical changes and chemical changes.

Answer: 1.  C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur

2. B)  [tex]NH_3[/tex]

3. B) Fluorine

Explanation:

1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.

Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7

Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.

2. A molecular compound is usually composed of two or more nonmetal elements. Example: [tex]NH_3[/tex]

Ionic compound is formed by the transfer of electrons from metals to non metals. Example: [tex]Mg_3N_2[/tex] , [tex]AlCl_3[/tex] and [tex]LiBr[/tex]

3.  For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas [tex]F_2[/tex]

Heat needed to raise the temperature : Q = 3432 J

Given

c = The specific heat capacity = 2.20 J/g-K

m = mass = 5 g

Δt = Temperature difference = 75-36 =39 °C=312 K

Required

Heat needed

Solution

Heat can be formulated

Q = m.c.Δt

Input the values :

Q = 5 g x 2.2 J/g-K x 312 K

Q = 3432 J

Answer:

5 its just what i do

Explanation: