During a solar eclipse, which of the following is true?
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Calcium (Ca) is in group 2 and period 4 on the periodic table be because Calcium has 2 valence electrons and 4 electron shell. Thus, calcium is a metal like all other group 2 element.

The correct answer to the question is Option C. Calcium, like all group 2 elements, is reactive and a solid at room temperature.

Calcium is a group 2 element majorly because it has 2 valence electrons. It is also in period 4 because it has 4 electron shells.

Being a group 2 element, calcium is a solid at room temperature and also reactive. All elements in the group 2 are metals.

There are other elements in period 4 which are not solid. For example krypton is an element in period 4 and it is a gas and not reactive.

From the above information, we can conclude that the correct answer to the question is:

Option C. Calcium, like all group 2 elements, is reactive and a solid at room temperature.

See attached image

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Answer:

The solvent

Explanation:

After the solid is recoverd by decanting the liquid, some solvent particles may still adhere to the solid.

In order to remove the solvent that may have adhered to the solid completely , the solid is washed before it is now dried.

In order to remove the remaining liquid present the solid material.

We are washing the solid in order to remove the liquid particles that is attached to the solid material with the help of water. Water is a universal solvent that dissolve large number of solutes in it.

Water removes the liquid from the solid by attaching with that liquid or dissolving in it so that's why we use water for washing a solid in order to remove the impurities from the solid material in which it is placed.

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Answer:

Exothermic

Explanation:

Nuclear fission means splitting, so there is a lot of energy being released.

Answer:

5

Explanation:

The image attached shows the different monochlorination products obtained when chlorine gas is heated with methylcyclobutane.

We must keep in mind that the reaction occurs by free radical mechanism as shown in the image attached. The proportion in which the products are formed depends on the stability of the free radical intermediate leading to that particular product.

Image credit: askiitians

Answer:

C

Explanation:

Answer:

b. No

Explanation:

The question above is related to "The Law of Conservation of Mass." This law states that mass is neither created nor can it be destroyed. Even if a particular matter will be mixed with another substance or it undergoes chemical reaction, the mass of the matter will remain the same. Even with a change in phase, the mass of the matter will remain the same.

Answer:

There are 76728.2 pounds of snow on the roof

Explanation:

To determine how many pounds of snow are on the roof,

First we will determine the mass of the snow in grams.

From the question,

Density of snow = 0.35 g/cm³

From

Density = Mass / Volume

To determine the mass, we will first find the volume.

From the question, a flat roof that is 35 by 43 feet has 28 inches of snow on it, that is, the height of the snow on the roof is 28 inches.

Area of the roof = 35 ft × 43 ft = 1505 ft²

Volume of the snow = Area of the roof × Height of the snow

Height of the snow = 28 inches

12 inches = 1 foot

∴ 28 inches = 28/12 feet = 2.3333 ft

Hence,

Volume of the snow = 1505 ft² × 2.3333 ft = 3511.62 ft³

Volume of the snow = 3511.62 ft³

This is the volume of the snow in cubic feet

Now, we will convert cubic feet (ft³) to cubic centimeter (cm³)

1 ft = 30.48 cm

and 1 ft³ = 30.48³ cm³ = 28316.84659 cm³.

If 1 ft³ =  28316.84659 cm³

∴ 3511.62 ft³ will be 3511.62 × 28316.84659 cm³ = 99438004.83 cm³

Hence, Volume of snow = 99438004.83 cm³

Now, we can determine mass of snow in grams

From

Density = Mass / Volume

Mass = Density × Volume

Mass = 0.35 g/cm³ × 99438004.83 cm³

Mass = 34803301.69 g

Now, we will convert the mass from grams to pounds

1 pound = 453.592 grams

If 453.592 grams = 1 pound

Then, 34803301.69 g will be 34803301.69 / 453.592 pounds = 76728.2 pounds

Hence, there are 76728.2 pounds of snow on the roof.

Answer:

Kinetic Energy is the correct Answer.

Explanation:

At the highest point on the roller coaster (assuming it has no velocity), the object has a maximum quantity of gravitational potential energy. As the object begins moving down to the bottom, its gravitational potential energy begins to decrease and the Kinetic Energy starts to increase.

Answer:

c,a,b,d

Explanation:

Answer:

As the atomic number of elements increases, the melting point increases because there are more electrons around the nucleus, which creates a stronger negatively-charged force. With stronger forces, the melting point rises. 3. Non-metals usually have low melting points.

Explanation:

The melting point rises as the atomic number of elements increases because there are more electrons surrounding the nucleus, creating a stronger negatively charged force. The melting point rises as the forces become stronger.

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Answer:

the answer is simple

Explanation:

jnnn B upper up of the eye color

Answer:

1. BBEE

2. BbEe

3. BBee

4. BbEE

5. bbEE

6. bbEe

7. Bbee

8.bbee

Answer:

1. 14 moles of NH3 were produced.

2. 7 moles of CO2 were produced.

3. 7 moles of H2O were produced.

Explanation:

We'll begin by writing a balanced equation for the decomposition of ammonium carbonate, (NH4)2CO3.

This is illustrated below:

(NH4)2CO3(s) —> NH3(g) + CO2(g) + H2O(g)

There are 2 atoms of N on the left side and 1 atom on the right side. It can be balance by putting 2 in front of NH3 as shown below:

(NH4)2CO3(s) —> 2NH3(g) + CO2(g) + H2O(g)

Now the equation is balanced.

From the balanced equation above,

1 mole of (NH4)2CO3 decompose to produce 2 moles of NH3, 1 mole of CO2 and 1 mole of H2O.

1. Determination of the number of mole of NH3 produced.

From the balanced equation above,

1 mole of (NH4)2CO3 decompose to produce 2 moles of NH3.

Therefore, 7 moles of (NH4)2CO3 will decompose to produce = 7 × 2 = 14 moles of NH3.

Therefore, 14 moles of NH3 were produced.

2. Determination of the number of mole CO2 produced.

From the balanced equation above,

1 mole of (NH4)2CO3 decompose to produce 1 mole of CO2.

Therefore, 7 moles of (NH4)2CO3 will also decompose to produce 7 moles of CO2.

Therefore, 7 moles of CO2 were produced.

3. Determination of the number of mole of H2O produced.

From the balanced equation above,

1 mole of (NH4)2CO3 decompose to produce 1 mole of H2O.

Therefore, 7 moles of (NH4)2CO3 will also decompose to produce 7 moles of H2O.

Therefore, 7 moles of H2O were produced.

Answer:

Mass = 23.232 g

Explanation:

Given data:

Mass of C₈H₁₈ = 7.58 g

Mass of CO₂ produced = ?

Solution:

Chemical equation:

2C₈H₁₈ + 25O₂      →     16CO₂ + 18H₂O

Number of moles of octane:

Number of  moles =  mass/molar mass

Number of moles = 7.58 g/ 114.23 g/mol

Number of moles = 0.066 mol

Now we will compare the moles of CO₂ with octane from balance chemical equation.

                  C₈H₁₈            :           CO₂

                       2              :              16

                 0.066             :           16/2×0.066 = 0.528

Mass of CO₂ produced:

Mass = number of moles × molar mass

Mass = 0.528 mol × 44 g/mol

Mass = 23.232 g

Answer:

K₂ = 1.12s⁻¹

Explanation:

Based on Arrhenius equation:

ln K₂/K₁ = -Ea/R (1/T₂ - 1/T₁)

Where K is rate constant,

R is gas constant (8.314J/molK),

T is absolute temperature (In K) Of 1, initial state and 2, final state.

ln K₂/K₁ = -Ea/R (1/T₂ - 1/T₁)

ln K₂/2.10x10⁻²s⁻¹ = -82000J/mol/8.314J/molK (1/(273.15 + 58) - 1/(273.15 + 19))

ln K₂ / 2.10x10⁻²s⁻¹ = 3.976

K₂ / 2.10x10⁻²s⁻¹ = 53.3

Answer:

PH = 4.0

Explanation:

We are given;

Ka1 = 8.9 × 10^(-8)

Ka2 = 1.0 × 10^(-19)

From the 2 values of K given above, we can see that Ka2 is far smaller than Ka1.

Thus, Positive hydrogen ion (H+) will be majorly formed from first dissociation which is Ka1.

Now, the breakdown of the H2S solution is;

H2S⇌[H+] + [HS−]

Thus;

Ka1 = [[H+] × [HS2^(-)]]/(H2S)

HS2^(-) also has a positive hydrogen ion.

Thus, we can rewrite as;

Ka1 = [[H+] × [H+]]/(H2S)

Ka1 = (H+)²/(H2S)

Concentration of H2S is given as 0.1M. Thus;

8.9 × 10^(-8) = (H+)²/0.1

(H+)² = 0.1 × 8.9 × 10^(-8)

(H+) = √(0.1 × 8.9 × 10^(-8))

(H+) = 0.00009433981

Now, PH is gotten from;

PH = -log (H+)

Thus;

PH = -log 0.00009433981

PH ≈ 4.0

Answer:

[tex]1.2x10^{38}\frac{fg}{cm^3}[/tex]

Explanation:

Hello there!

In this case, for such unit conversion we need to realize that 1 kg is equal to 1000 g, 1 g is equal to 1x10⁹ and 1 mL equals 1 cm³, therefore we apply:

[tex]12x10^{25}kg*\frac{1000g}{1kg} *\frac{1x10^9fg}{1g} *\frac{1mL}{1cm^3} \\\\1.2x10^{38}\frac{fg}{cm^3}[/tex]

Best regards!

Answer:

the second answer its science behind it

Answer:

b

Explanation:

Answer:

The frequency is  [tex]f =  2,01 * 10^{15} \  Hz  [/tex]

Explanation:

From the question we are told that

   The energy required to ionize boron is [tex]E_b  =  801 KJ/mol[/tex]

Generally the ionization energy of boron pre atom is mathematically represented as

     [tex]E_a  =  \frac{E_b}{N_A}[/tex]

Here  [tex]N_A[/tex] is the Avogadro's constant with value [tex]N_A  =  6.022*10^{23}[/tex]

So

      [tex]E_a  =  \frac{801}{6.022*10^{23}}[/tex]

=>     [tex]E_a  =  1.330 *10^{-18} \  J/atom [/tex]

Generally the energy required to liberate one electron from an atom is equivalent to the ionization energy per atom and this mathematically represented as

       [tex]E =  hf  =  E_a[/tex]

=>     [tex]  hf  =  E_a[/tex]

Here h is the Planks constant with value [tex]h = 6.626 *10^{-34}[/tex]

So

       [tex]f =  \frac{1.330 *10^{-18}}{ 6.626 *10^{-34}}[/tex]

=>      [tex]f =  2,01 * 10^{15} \  Hz  [/tex]

Answer:

0.0611M of HNO3

Explanation:

The concentration of the NaOH solution must be 0.1198M

The reaction of NaOH with HNO3 is:

NaOH + HNO3 → NaNO3 + H2O

1 mole of NaOH reacts per mole of HNO3.

That means the moles of NaOH used in the titration are equal to moles of HNO3.

Moles HNO3:

12.75mL = 0.01275L * (0.1198mol / L) = 0.0015274 moles NaOH = Moles HNO3.

In 25.00mL = 0.025L -The volume of the aliquot-:

0.00153 moles HNO3 / 0.025L =

Complete Question

You are given a solution containing a pair of enantiomers (A and B). Careful measurements show that the solution contains 98% A and 2% B. What is the enantiomeric excess?

Answer:

The value is  [tex]k  = 96 %[/tex]

Explanation:

From the question we are told that

   The  percentage of  enantiomer A is  A =  98%

    The  percentage of  enantiomer B is  B =  2%

Generally the enantiomeric excess is mathematically represented as

      [tex]k  =  \frac{A -B}{A+B}  *  100[/tex]

=>   [tex]k  =  \frac{98 -2}{98+2}  *  100[/tex]

=>   [tex]k  = 96 %[/tex]

Answer:

5Ns

momentum= mass *velocity

=1*5

=5Ns

Answer:

Explanation:

The new volume can be found by using the formula for Boyle's law which is

[tex]P_1V_1 = P_2V_2[/tex]

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

Since we are finding the new volume

[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]

We have

[tex]V_2 = \frac{300 \times 2}{7} = \frac{600}{7} \\ = 85.714285...[/tex]

We have the final answer as

Hope this helps you

Answer:

Several extractions is more effective than a single extraction.

Explanation:

When extraction is carried out multiple times, for instance, in this case, the extraction was carried out with three portions of the solvent rather than with just a single portion of the solvent, the amount of material left in the residue will be lower, because the extraction is more complete.

Several extractions with smaller volumes of solvent are more effective than a single extraction with a large volume of solvent.

Answer:

polar bonds are caused by different kind of atoms, because almost every atoms have different powers to attract electrons.

the answer will be the two same atoms, F2

Answer:

I think it's A and D

Explanation:

I'm not sure if it's right

Answer:

The answer is B and D

Explanation:

trust fr

Grams of BW

i think thats irtu9rgirg

Independent variable in an investigation is the variable is does not depends on any other variable and on which we can have the control. Hence, the grams of BW is the independent variable here.

In an experiment the parameters which changes by control or depending on other changes are called variables. There are two kinds variables namely dependant and independent variables.

The dependant variables are those variable which depends upon other variables and whose changes are studying with respect to certain parameters.

Independent variables does not depends on other variable and can be controlled by the researcher. Here, we are studying the % of developing cold with respect to the amounts of BW. The changing variable is BW amount on which the percentage of cold depends.

Therefore, the independent variable is grams of BW and dependant variable is % development of cold.

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Answer:

i wish i could help but t know either so i wish you luck for an answer once again truly sorry don'

Explanation:

i am sorry but i do not know :(

Answer:

Cave Crystal

Explanation:

I believe it's cave crystal because sand dunes, river deltas, and valleys are all examples of deposition.