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Answer : 2 represent the coefficient.

Explanation :

As we know that:

The coefficients used in the chemical equations shows that the relative amounts of each substance present and this amount can represent either the relative number of molecules or number of moles.

If there is no coefficient then one (1) is assumed.

That means,

The coefficient tell us about that how many molecules or atoms present in the chemical equation.

By the stoichiometry we have to convert moles of a reactant to moles of a product.

The given formula is: [tex]2CH_4[/tex]

In this formula, 2 represent the coefficient and 4 represent the subscript and C and H represents the symbol of element.

Hence, 2 represent the coefficient.

Explanation:

Examples of chemical changes include, rusting, fire, and overcooking. Nuclear changes occur when the nuclei of atoms are rearranged to form new atoms. Examples of nuclear changes include atomic fission, nuclear fusion, and the energy of sun and stars.

Answer:

7 dots

Explanation:

Answer:

63.55

Explanation:

4.500 x 10^5 amu x 1 Cu atom / 63.55 amu = 7081 Cu Atom

Cu 1 x 63.55 = 63.55

Answer: 4.6 billion years ago

Explanation:

Answer:

4.6 billion years ago

hope this helps have a good day or night:)

Moles of Na theoretically extract : 10.256

Given

600 g of NaCl

Required

moles of Na

Solution

Na can be electrolyzed from NaCl(molten)

Na⁺ + e⁻⇒ Na

Cl⁻⇒1/2 Cl₂ + e⁻

Overall reaction :

NaCl⇒Na + 1/2 Cl₂ x2

2NaCl⇒2Na + Cl₂

mol of NaCl(MW=58.5 g/mol) :

= 600 g : 58.5 g/mol

= 10.256

From the equation, mol ratio of NaCl : Na = 2 : 1, so :

mol Na = mol NaCl = 10.256

Answer:

R = V / I

Explanation:

Ohm's Law:

V = I * R , V = voltage , I = current , R = resistance

rearranging to solve R,

R = V / I

Answer:

R = V / I

Explanation:

Answer:

I would say the answer is 2

The formation of new mountains due to tectonic movements is reporting now whereas, some of  the olden mountains are worn down. Thus option 2 is correct.

Earth crests is made of tectonic plates of different sizes and shapes. These plates were not apart and was one in the earlier times of earth and no separate continents were there. When heat in the atmosphere made the magma hot and the hot fluid flow makes the plate moving.

The tectonic plate movement is different in different regions and its results be different. Some movements results in the formation of mountains mostly when the plates are moving each other and one plate rise the edge of others.

Some movement results in islands, folded mountains, volcanic mountains etc. These mountains may worn down over time and there is a possibility of formation of new mountains in regions where significant plate movement occurs.

To find more about  plate movement, refer the link bellow:

https://brainly.com/question/3970445

#SPJ2

Answer:

hey i saw you asked about the kinetic energy lab report on edg and i was wondering if you ever finished it and could send it me plzzzzzzzz

Explanation:

Answer:

C. 8 eV

Explanation:

In atoms, the energy of each level is quantised. That is one of the reasons why an electron can not exist between energy levels. Thus, when the electron absorbs energy of 8 ev, it get excited and jumps to energy level 2 which has the current value of energy of the electron.

Thus for the electron to move back to its initial energy level, it must emit the exact energy absorbed for its excitation. Therefore, the likely energy of the photon that will be emitted is 8 ev. This would make the electron to have energy that would make it to exist on energy level 1.

B. 0.21 mol

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Step 1: Define

1.25 × 10²³ atoms Ca

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

0.207572 mol Ca ≈ 0.208 mol Ca

Answer:

Ohm/ Current = Resistance

Explanation:

Answer:

Ohm

Explanation:

Answer:

In increasing order:

Sr, Ca, Mg, Br

Answer:

Density = 2.09×10⁻³ g/mL

Explanation:

We solve this problem from the Ideal Gases Law.

P . V = n . R . T

We know that in STP conditions 1 mol of any gas occupies 22.4 L. So we can compare both situations.

22.4 L = 22400 mL

(P₁ . V₁) / T₁ = (P₂ . V₂) / T₂

We make some conversions:

97°C + 273 = 370 K

755 mmHg . 1 atm / 760mmHg = 0.993 atm

We replace data: (1 atm . 22400 mL) / 273 K = (0.993 atm . V₂) / 370 K

((1 atm . 22400 mL) / 273 K) . 370K = 0.993 atm . V₂

V₂ = 30359 atm . mL / 0.993 atm → 30573 mL

Under those conditions (97 °C and 755 mm Hg) 1 mol of gas is contained in 30573 mL.

We determine the amount of gas: 1 mol of SO₂ weighs 64.06g

Density = m/V → 64.06 g / 30573 mL = 2.09×10⁻³ g/mL

Answer:

[tex]\Delta s=-23.0\frac{J}{mol*K}[/tex]

Explanation:

Hello!

In this case, since the entropy change when an ideal gas undergo both a volume and temperature change is computed by:

[tex]\Delta s =Cp*ln(\frac{T_2}{T_1} )-R*ln(\frac{P_2}{P_1} )[/tex]

Whereas the molar Cp is 20.786 J/(mol*K) and the final pressure is computed via the Boyle's law:

[tex]P_2=\frac{1.00atm*500cm^3}{50cm^3}=10 atm[/tex]

Thus, we plug in the data (temperatures in Kelvin) to obtain:

[tex]\Delta s =20.786\frac{J}{mol*K} *ln[\frac{(-25+273)K}{(25+273)K} ]-8.3145\frac{J}{mol*K}*ln(\frac{10atm}{1atm} )\\\\\Delta s=-23.0\frac{J}{mol*K}[/tex]

Best regards!

Answer:

28). 261

29). 788

30).-6201

Explanation:

I just took lesson and it said those were correct, I added screenshots of the lesson if you need it :)

Answer:

Nine σ- and nine π

Explanation:

Nine σ- and nine π are there in the molecule of tetracyanoethylene.

Answer:

There are 65.38 grams are in 0.75 moles of zinc?

We assume you are converting between moles Zinc and gram. You can view more details on each measurement unit: molecular weight of Zinc or grams The molecular formula for Zinc is Zn. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Zinc, or 65.38 grams.

Answer:

Number of protons=17

Halogen

Explanation:

Given,

The electronic configuration:[tex]1s^2, 2s^2, 2p^6, 3 s^2, 3 p^5[/tex]

Atomic number= 2+2+6+2+5 = 17

Chlorine has the atomic number 17.

Symbol of chlorine= Cl

We know that,

The number of protons is equal to the atomic number.

Number of protons=17

And Chlorine belongs to the halogen group of the periodic table.

Answer:

Calcium carbonate and citric acid.

Explanation:

Hello!

In this case, considering the text, we can notice that calcium carbonate combines with citric acid to produce the calcium citrate water and carbon dioxide as shown on the following equation:

[tex]3CaCO_3+2C_6H_8O_7\rightarrow Ca_3C_{12}H_{10}O_{14}+CO_2+H_2O[/tex]

Whereas the reactants, at the left side, are identified as calcium carbonate and citric acid.

Best regards!

Answer:

1.25 g/cm^3

Explanation:

D = M/V

Mass is 120g

Volume is 96 ml

So you do 120/96 and you get your final answer as 1.25

Hope it helped!

Answer:

 -47749.69 joule energy release.

Explanation:

Given data:

Mass of water = 777.1 g

Initial temperature = 57.3°C

Final temperature = 42.6 °C

Energy change = ?

Solution:

Specific heat capacity of water is 4.18 J/g.°C

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 42.6 °C - 57.3°C

ΔT = -14.7°C

Q = 777.1 g × 4.18J/g.°C ×  -14.7°C

Q =  -47749.69 J

 -47749.69 joule energy release.

Answer: small, whole-number ratio

Explanation: 1) A compound consists of atoms of two or more elements combined in a small, whole-number ratio. In a given compound, the numbers of atoms of each of its elements are always present in the same ratio

Answer:

fixed proportion

Explanation:

Answer:

Mixtures are unlike chemical compounds, because: The substances in a mixture can be separated using physical methods such as filtration, freezing, and distillation.

Answer:

9.48 L.

Explanation:

Hello!

In this case, as the problem mentions a long way to solve it, we are going to apply it because it can provide the answer more rapidly; thus, considering that 112 km are required, 1 mile equals 1.609 km and 1 gallon equals 3.785 liters, we can set up the proportional factor as shown below:

[tex]112km*\frac{1mi}{1.609 km}*\frac{1gal}{27.8mi}*\frac{3.785L}{1gal}[/tex]

Whereas km, mi and gal are cancelled out as it turns out in L; therefore the required liters are:

[tex]9.48L[/tex]

Best regards!

Answer:

[tex]S_2F_{10}[/tex]

Explanation:

Hello!

In this case, since the empirical formula of a chemical compound is determined by assuming the by-mass percentages are masses, we can firstly compute the moles of sulfur and fluorine based on their atomic masses:

[tex]n_S=25.24gS*\frac{1molS}{32.01gS}=0.789molS\\\\n_F=74.76gF*\frac{1molF}{19.00gF}=3.93molF[/tex]

Next, we compute the subscript of each element in the formula by dividing each moles by the fewest moles:

[tex]S=\frac{0.789}{0.789}=1\\\\F=\frac{3.93}{0.789} =5[/tex]

Whose molar mass is 127.01 g/mol. Now, we can compute the ratio between the molecular and empirical formulas as follows:

[tex]ratio=\frac{254.14}{127.01} =2[/tex]

Thus, the molecular formula is:

[tex]S_2F_{10}[/tex]

Regards!

The empirical formula of the compound : Cu₂O

Given

66.41 g Cu

8.56 g O

Required

The empirical formula

Solution

1. Find mol

mol = mass : Ar

mol = 66.41 : 63.5

mol = 1.046

mol = 8.56 : 16

mol = 0.535

2. mol ratio

Cu : O (divide by smallest mol⇒0.535) :

[tex]\tt \dfrac{1.046}{0.535}\div \dfrac{0.535}{0.535}=2\div 1[/tex]