the normal human eye responds to visible light of wavelength range from about 390 to 710nm. Determine the frequency range of the human eye.​

i think it's a simple covalent structure

in test tube 1 iron nail gets both air and moisture which is required for rusting. ... in the test tube 3 iron nail is not rusted because of the calcium chloride which is moisture absorber. hence nail would not get moisture for the rusting.

Answer:

Explanation:

AND REMEMBER DO ALWAYS READ AND WRITE

Answer:

A compound is something like atoms coming together as a team, and a mixture is 2 or more substances mixing together.

Explanation:

The ratio of molecules in sulphur dioxide and methane will be the same as the ratio of their moles. So, first of all we should find out the number of moles of sulphur dioxide in 1 gram of sulphur dioxide in 1 gram of sulphur dioxide, and the number of moles of methane in 1 gram of methane. This can be done as follows :

(i) The molecular formula of sulphur dioxide is [tex]SO_{2}[/tex]

So, [tex]1[/tex]  mole of [tex]SO_{2}[/tex] = [tex]Mass[/tex] [tex]of[/tex] [tex]2'O'[/tex]

[tex]=32+2*16[/tex]

[tex]= 64[/tex] grams

Now, [tex]64g[/tex] of sulphur dioxide [tex]= 1[/tex] mole

So, [tex]1g[/tex] of sulphur dioxide = [tex]\frac{1}{64}[/tex] mole

Thus, we have [tex]\frac{1}{64}[/tex] mole of sulphur dioxide and it contains molecules in it. Now, since equal moles of all the substance contain equal number of molecules, therefore, [tex]\frac{1}{64}[/tex] mole of methane will also contain x molecules of methane.

(ii) Molecular formula of methan is [tex]CH_{4}[/tex]

So, 1 mole of [tex]CH_{4}[/tex]  = Mass of C + Mass of 4 H

[tex]=12+4*12[/tex]

Now, 16g of methane = 1 mole

So, 1 g of mathane = [tex]\frac{1}{16}[/tex] mole

We know that:

[tex]\frac{1}{64}[/tex] mole of methane contains = x molecules

So, [tex]\frac{1}{16}[/tex]  mole of contains will contain =[tex]\frac{x*64}{16}[/tex] molecules

=[tex]4x[/tex] molecules

According to Dalton's atomic theory, atoms of different elements combine in simple whole-number ratios to form compounds.

As the name implies, Dalton's atomic theory is a theory proposed by an English scientist named John Dalton in the 1900's.

The Dalton's atomic theory is composed of five main parts, which are as follows:

Therefore, in accordance to Dalton's atomic theory, atoms of different elements combine in simple whole-number ratios to form compounds.

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Answer:

Q= ms∆T

Where, m is mass of substance

S is specific heat

∆T is temperature change

As in question , m=8.21 ,s=0.13 ,∆T =6.2

So, Q = 8.21×0.13×6.2=6.61 J

I believe the answer would be D

Answer:

About 7.0 × 10³ J or 7.0 kJ

Explanation:

We want to determine the amount of energy needed to raise the temperature of 67 grams of water from 20°C to 45°C.

We can use the heat equation:

[tex]\displaystyle q = mC\Delta T[/tex]

Where C is the specific heat of water.

Substitute and evaluate:

[tex]\displaystyle \begin{aligned} q & = (67\text{ g})\left(\frac{4.2\text{ J}}{\text{g-$^\circ$C}}\right)\left(45^\circ \text{ C}- 20.^\circ\text{ C}\right) \\ \\ & = (67\text{ g})\left(\frac{4.2\text{ J}}{\text{g-$^\circ$C}}\right)(25^\circ \text{ C}) \\ \\ & = 7.0\times 10^3 \text{ J}\end{aligned}[/tex]

Recall that there are 1000 J in a kJ. Hence:

[tex]\displaystyle \begin{aligned} q & = 7.0\times 10^3 \text{ J} \cdot \frac{1\text{ kJ}}{1000\text{ J}} \\ \\ & = 7.0 \text{ kJ}\end{aligned}[/tex]

In conclusion, it will take about 7.0 × 10³ J or 7.0 kJ of energy to raise the temperature of 67 grams of water from 20 °C to 45 °C.

Answer:

Explanation: Atomic weight is measured in atomic mass units (amu), also called daltons.

Covalent compounds are generally not very hard because they are formed by two or more nonmetallic atoms.

Covalent compounds are compounds whose constituent elements are joined together by covalent bonds.

Covalent bonding occurs when two or more nonmetallic atoms of an element share valence electrons. This means that covalent compounds will not be physically hard since they constitute non-metals.

Examples of covalent compounds are:

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The formula for calculating the amount of energy or heat released is:

ΔH = C ΔT

where ΔH is heat of combustion, C is heat capacity, while ΔT is change in temperature

ΔH = 8.69 kJ / °C * (5.14°C)

ΔH = 44.67 kJ

Then we calculate the moles of CH3OH which has molar mass of 32.04 g/mol:

moles = 1.922 / 32.04 = 0.05999 mol

SO the molar heat of combustion is:

ΔHm = 44.67 kJ / 0.0599875 mol

ΔHm = 744.60 kJ / mol

Answer:

C. 4%

Explanation:

The answer is 4%

Answer:

There are 27 Valence electrons : )

4+1+1+1+6+4+1+1+4+1+1+1 is 27

Explanation:

There are a total of [5×1]+[2×4]+[7]=21[5×1]+[2 × 4 ] + [ 7]=21 valence electrons

Answer:it's b hope that help

The molar mass of water is 18 g. Given that there are 0.23 teaspoon for every 1 g. Thus , for 18 g there would be 4.14 teaspoons.

Any substance that contains  6.022 × 10²³ number of atoms is called one mole of that substance. The mass of a compound or molecule containing these much atoms is called its molar mass.

Molar mass of water is 18 g. Thus, it means that one mole of water weighs 18 g. Given that for every 1 g of water there are 0.23 teaspoon. Thus, number of teaspoons for one mole or 18 g of water is:

number of teaspoons = 18 g × 0.23  /1 g

                                    = 4.14 teaspoons.

Therefore, 4.14 teaspoons are required for one mole of water.

To find more on molar mass, refer here:

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The branched alkanes in boxes two and three all have molecular formula C6H14 and are isomers of the compound shown.

Isomers are compounds that has the same molecular formula but different structural formulas. Hence, isomers of compounds can be represented by the same molecular formula since they contain the same number of each atom.

The molecule shown has molecular formula C6H14. The branched alkanes in boxes two and three all have molecular formula C6H14 and are isomers of the compound shown.

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Considering the Dalton's partial pressure, the correct answer is option a.: the total pressure of the mixture is 1.86 atm.

The pressure exerted by a particular gas in a mixture is known as its partial pressure. So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:

[tex]P_{T} =P_{1} +P_{2} +...+P_{n}[/tex]

where n is the amount of gases present in the sample.

This relationship is due to the assumption that there are no attractive forces between the gases.

In this case, a mixture contains 220 mmHg of CO, 350 mmHg of Ne and 840 mmHg of He. The total pressure of the mixture can be calculated as:

[tex]P_{T} =P_{CO} +P_{Ne} +P_{He}[/tex]

[tex]P_{T} =220 mmHg +350 mmHg+840 mmHg[/tex]

Solving:

[tex]P_{T}[/tex]= 1410 mmHg

Being 760 mmHg=1 atm, then:

[tex]P_{T}=1410 mmHgx\frac{1 atm}{760 mmHg}[/tex]

Solving:

[tex]P_{T}[/tex]= 1.86 atm

Finally, the correct answer is option a.: the total pressure of the mixture is 1.86 atm.

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➡PV = nRT

➡PV = (W/M)RT

➡PM = (W/V)RT

➡PM = PRT

➡P = pRT/M

➡P = 2.85 × 0.082 x 298 / 44

➡P = 1.583 atm

➡P = 1.583 × 760

➡P = 1203 mm Hg

Hope this helps you:)

Answer:

liquid and gas........................

Answer:

The Moon has an atmosphere.

Explanation:

The Moon has an atmosphere, but it is very tenuous. Gases in the lunar atmosphere are easily lost to space. Because of the Moon's low gravity, light atoms such as helium receive enough energy from solar heating so that they escape in just a few hours.

Answer:

10.53m/s

Explanation:

Initial velocity: 13m/s

Angle of projection: 55deg

Y-component of velocity is given as usin⌀

Plugging in, we get

= 13 * sin(55deg)

= 13 * 0.81

= 10.53

⇒ 10.53m/s

Answer:

Ca = 40.1 g

Cl = 35.5

40.1 + 35.5×2

40.1 + 71

111.1 g

Answer:

the bond is ionic

Explanation:

Answer: Its C, c is a solid state

the answer :

Hi there !

The answer is "C"

; due to the intermolecular forces of attraction

Very Very sorry

The replacement reaction will not occur because iodine is less reactive than chlorine.

A replacement reaction is a type of reaction in which one element is replaced by another in a compound.

The principle behind one element replacing the other is based on the reactivity of an element. A more reactive element will displace a less reactive one.

According to this question, the following displacement reaction is given: MgCl2 + I2 → ?

This reaction will not occur because chlorine is more reactive/electronegative than iodine, hence, iodine cannot displace it.

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Answer:

D

Explanation:

The valence electrons are the outer electrons and must be located in the outermost shell. In this case, D.