What is the only way to be certain that a chemical change has occurred

Answer: 0.671614483912211

Explanation: A mole is 6.02214076×1023 (also known as the Avogadro number) I hope this helps!

Answer:

Because of reaction between solid and liquid

Answer:

shouldn't take that long i would say from 30 to 40 minutes bc its melting in warm water its turning from a solid to a liquid.

Explanation:

The number of atoms in 1 mole of carbon equals the number of atoms in 1 mole of boron is false because the molar mass of carbon is different from that of boron. Option A is correct.

From the listed option the number of atoms in 1 mole of carbon equals the number of atoms in 1 mole of boron is false because the molar mass of carbon is different from that of boron

Learn more on moles here: https://brainly.com/question/24256751

The mole fraction of the other gases : 0.52

Given

P tot = 2.5 atm

P x = 1.2 atm, n = 0.85 moles

Required

mole fraction

Solution

P tot = P gas X + P other gases

mol fraction = mol x : mol total

P gas X = mol fraction gas X x P total

1.2 atm = mol fraction gas X x 2.5 atm

mol fraction gas X = 0.48

mol fractionof the other gases = 1 - 0.48 = 0.52

Or we can use

P other gases = 2.5 - 1.2 = 1.3 atm

mol fraction the other gases = 1.3 : 2.5 = 0.52

Answer:

Like other legumes, peanut plants improve the soil by adding nitrogen, even as they grow tasty, nutritious nuts for this season's harvest. But peanuts need help as they take nitrogen from the air and "fix" it into the soil via their root systems.

Explanation:

Answer:

B hope it helps

Explanation:

Answer:

A: CH4 + 2O2 -> CO2 + 2H2O

Explanation:

Count how many elements they are in all molecules for the reactants and for the products.

C = 1 element

H = 4 elements

O = 2 elements

C = 1 element

O = 2 elements

H = 2 elements

O = 1 element

2 oxygen atoms + 1 oxygen atoms = 3 oxygen atoms total on the products side.

To balance this equation, we need to add 2 more elements of hydrogen and 2 more elements of oxygen. Therefore, we add a 2 to the coefficient of O2 for the reactants side and add a 2 to the coefficient of H2O for the products side.

Now let us try it.

Count how many elements they are in all molecules for the reactants and products.

C = 1 element

H = 4 elements

O = 4 elements

C = 1 element

O = 2 elements

H = 4 elements

O = 2 elements

2 oxygen atoms + 2 oxygen atoms = 4 oxygen atoms total on the products.

All of the elements are balanced.

Hope it helped!

Answer:

Hey!

Explanation:

I dont know the answers but Cell walls and Cloroplasts are only in plant cells. I hope this helps!

Answer:

17.6

Explanation:

Answer is explained above

Answer:

The numerical value of K for the reaction is 2.36*10⁻⁴

Explanation:

A chemical equilibrium is a reaction that is never completed, since it occurs simultaneously in both directions (the reactants form products, and in turn, these form reactants again). In other words, it is a dynamic balance. When the concentrations of each of the substances involved (reactants or products) stabilize, that is, they are spent at the same rate as they are formed, chemical equilibrium is reached.

The equilibrium constant (Kc) is expressed as the ratio between the molar concentrations of reactants and products. Its value in a chemical reaction depends on the temperature, so this must always be specified.

Being:

aA + bB ⇄ cC + dD

then the constant Kc is:

[tex]Kc=\frac{[C]^{c} *[D]^{d} }{[A]^{a} *[B]^{b} }[/tex]

In the case of the reaction:

A₂(g) + 3 B₂(g) ⇒ 2 AB₃(g)

The constant Kc is:

[tex]Kc=\frac{[AB_{3} ]^{2} }{[A_{2} ] *[B_{2} ]^{3} }[/tex]

Being:

and replacing, you get:

[tex]Kc=\frac{(7.6*10^{-4} )^{2} }{0.0055 *(0.763)^{3} }[/tex]

Kc=2.36*10⁻⁴

The numerical value of K for the reaction is 2.36*10⁻⁴

Answer:

Establish and Use a Secure Connection

Use SSH Keys Authentication

Secure File Transfer Protocol

Secure Sockets Layer Certificates

Use Private Networks and VPNs

Explanation:

Answer:

C. The gills allow the fish to take in oxygen from the water.

Answer:

D

Explanation:

The volume of carbon monoxide is produced when 1.20 L of dicyanoacetylene reacts is

Stoichiometry of any reaction tells about rhe relative amount of substance present before and after the completion of any chemical reaction.

Given balanced chemical reaction between dicyanoacetylene and ozone to produce carbon monoxide and nitrogen is:

3C₄N₂ + 4O₃ → 12CO + 3N₂

From the stoichiometry of the reaction it is clear that:
3 liters of C₄N₂ =  produces 12 liters of CO

1.20 liters of C₄N₂ =  produces 12/3×1.20=4.8 liters of CO

Hence option (d) is correct i.e. 4.8 liters.

To know more about stoichiometry, visit the below link:
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Answer:

2K   +   2H₂O   →   2KOH  + H₂

Explanation:

The reactants are:

    Potassium metal  = K

    Water  = H₂O

 The products are:

  Potassium hydroxide  = KOH

  Hydrogen gas  = H₂  

The reaction equation is given as;  

                Reactants   →   Products

        2K   +   2H₂O   →   2KOH  + H₂

The reaction is a single displacement reaction

Answer:

132.14 g/mol

Explanation:

Answer:

[tex]2.11x10^{22}atoms[/tex]

Explanation:

Hello!

In this case, considering the Avogadro's number, which relates the number of particles and one mole, we can infer that 1 mole of any element contains 6.022x10²³ atoms as shown below:

[tex]\frac{6.022x10^{23}atoms}{1mol}[/tex]

Thus, we compute the number of atoms in 0.035 moles as shown below:

[tex]atoms=0.035mol*\frac{6.022x10^{23}atoms}{1mol} \\\\atoms=2.11x10^{22}atoms[/tex]

Best regards!

Answer:

Explanation:

HCl    + NaOH     =    NaCl    +     H₂O.

1 mole   1 mole           1 mole          1 mole

6.93  g of hydrochloric acid = 6.93 / 36.5 = .189 mole of HCl

2.4 g of NaOH = 2.4 / 40 =  .06 mole of NaOH

NaOH is in short supply so it is the limiting reagent .

1  mole of NaOH reacts with 1 mole of HCl to give 1 mole of Water

.06 mole of NaOH will react with .06 mole of HCl to give .06 mole of water

Water formed = .06 mole

= .06 x 18 = 1.08 g

= 1.1 g

Answer:

5 its just what i do

Explanation:

Explanation:

Let the mass of the compound be 100g.

There are 60.2g of sulfur.

Moles of sulfur

= 60.2g / (32.07g/mol) = 1.877mol

There are 100g - 60.2g

= 39.8g of manganese.

Moles of manganese

= 39.8g / (54.94g/mol) = 0.724mol

Mole ratio of manganese to sulfur

= 0.724mol : 1.877mol = 1 : 2.5.

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:

radiation

Explanation:

hope this helps!

Answer:

measured

Explanation:

no way can they pin point exactly when something lived when its in the millions

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:

Trial 1: Heat lost by the metal = -4100 J

Trial 2: Heat lost by the metal = -4042 J

Trial 3: Heat lost by the metal = -3940 J

Explanation:

Assuming that all of the heat lost by the metal  is transferred to the water and no heat is lost to the surroundings; Heat lost by metal = heat gained by water. Qmetal = -Qwater

Note: If the experiment was carried out in a calorimeter of known heat capacity, some heat is lost to the calorimeter.

Hence,  Qmetal = -(Qwater + Qcalorimeter)

Quantity  of heat, q = mass * specific heat capacity * temperature change

Trial 1

mass of water = 70.001 g

specific heat capacity of water = 4.184 J/g/°C

Initial temperature of water = 24.2 °C

final temperature of mixture = 38.2 °C

Temperature change of water = 38.2 - 24.2 = 14.0 °C

Heat gained by water = -(70.001 * 4.184 * 14.0) = -4100 J

Therefore, heat lost by the metal = -4100 J

Trial 2

mass of water = 70.008 g

specific heat capacity of water = 4.184 J/g/°C

Initial temperature of water = 24.0 °C

final temperature of mixture = 37.8 °C

Temperature change of water = 37.8 - 24.0 = 13.8 °C

Heat gained by water = -(70.008 * 4.184 * 13.8) = -4042 J

Therefore, heat lost by the metal = -4042 J

Trial 3

mass of water = 70.271 g

specific heat capacity of water = 4.184 J/g/°C

Initial temperature of water = 23.2 °C

final temperature of mixture = 36.6 °C

Temperature change of water = 36.6 - 23.2 = 13.4 °C

Heat gained by water = -(70.271 * 4.184 * 13.4) = -3940 J

Therefore, heat lost by the metal = -3940 J

Answer:

1.50 moles of POH or Potassium Hydroxide.

Explanation:

First of all, find the substance formula

The substance formula of Potassium Hydroxide is

KOH

Second of all, if you want to convert from grams to moles, you use molar mass of KOH

Third of all, find the molar mass of KOH.

K = 39.1 amu

O = 16.0 amu

H= 1.0 amu

Potassium has 1 atom, oxygen has 1 atom, and hydrogen has 1 atom.

So do this:

39.1(1) + 16.0(1) + 1.0(1) = 56.1

The molar mass of KOH is 56.1 g/mol.

Fourth of all, use dimensional analysis to show your work.

84.20 grams of KOH * 1 mol/56.1 g/mol

The moles will cancel out.

84.20 divided by 56.1 = 1.500892166

But I have to round my answer to two digits after the decimal points instead of using sig figs.

So I round to the hundredths place

1.500892166 = 1.50

So the final answer is 1.50 moles(don't forget the units) of POH.

Hope it helped!

The question is incomplete, the complete question is;

Silicon has three naturally occurring isotopes with thefollowing masses and natural abundances:

Isotope Mass ({\rm amu}) Abundance (%)

{\rm Si}-28 27.9769 92.2

{\rm Si}-29 28.9765 4.67

{\rm Si}-30 29.9737 3.10

Calculate the atomic mass of silicon.

Answer:

28.09 amu (to four significant figures)

Explanation:

Given that;

Isotope Mass  Abundance (%)

Si-28 27.9769 92.2

Si-29 28.9765 4.67

Si-30 29.9737 3.10

So we now have;

Relative atomic mass of silicon;

(27.9769  ×  0.9218)  +  (28.9765  ×  0.0471)  +  (29.9738  ×  0.0312)

25.789 + 1.365 + 0.9351 = 28.09 amu (to four significant figures)

Explanation:

In a chemical reaction, the atoms and molecules produced by the reaction are called products.

In a chemical reaction, only the atoms present in the reactants can end up in the products. No new atoms are created, and no atoms are destroyed.

In a chemical reaction, reactants contact each other, bonds between atoms in the reactants are broken, and atoms rearrange and form new bonds to make the products.

Answer:

wave length=speed*frequency

=36*6

=216 m