Which is an example of a physical change? (Select all that apply.)

digesting food

baking a cake

melting snow

boiling water

Answer:

2

Explanation:

Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability.

Answer:

To fill their valance shell and become stable!

Explanation:

Answer:

The [H⁺] for this soluton is 2*10⁻³ M

Explanation:

pH, short for Hydrogen Potential and pOH, or OH potential, are parameters used to measure the degree of acidity or alkalinity of substances.

The values ​​that compose them vary from 0 to 14 and the pH value can be directly related to that of pOH by means of:

pH + pOH= 14

In this case, pOH=11.30, so

pH + 11.30= 14

Solving:

pH= 14 - 11.30

pH= 2.7

Mathematically the pH is the negative logarithm of the molar concentration of the hydrogen or proton ions (H⁺) or hydronium ions (H₃O):

´pH= - log [H⁺] = -log [H₃O]

Being pH=2.7:

2.7= - log [H⁺]

[H⁺]= 10⁻² ⁷

[H⁺]=1.995*10⁻³ M≅ 2*10⁻³ M

The [H⁺] for this soluton is 2*10⁻³ M

The pH of the NaOH solution has been 2.7. The hydrogen ion concentration of the NaOH solution has been 1.9 \(\rm \bold{\times\;10^-^3}\) M.

The pH of the solution has been used for the determination of the Hydrogen ion concentration in the solution. The higher the hydrogen ion concentration, the pH will tend to be more towards the lower side.

The pOH has been the hydroxide ion concentration in the solution, The higher the hydroxide ion concentration, the more pH will move towards the higher range.

The sum of pH and pOH has been the constant quantity.

pH + pOH = 14

The given NaOH solution has pOH 11.30. The pH of the solution will be:

pH + 11.30 = 14

pH = 14 - 11.30

pH = 2.7.

The pH of the NaOH solution has been 2.7.

pH can be defined as the negative log of the hydrogen ion concentration.

pH = -log [\(\rm H^+\)]

2.7 = log [\(\rm H^+\)]

[\(\rm H^+\)] = \(\rm 10^-^2^.^7\)

[\(\rm H^+\)] = 1.9 \(\rm \bold{\times\;10^-^3}\) M

The hydrogen ion concentration of the NaOH solution has been 1.9 \(\rm \bold{\times\;10^-^3}\) M.

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Answer:

European Union was on grand committee

Answer:

European Union

Explanation:

hehe

The pOH of the 0.001 M NaOH solution is approximately 3.

To determine the pOH of a solution, we need to know the concentration of hydroxide ions (OH-) in the solution.

In the case of a 0.001 M NaOH solution, we can assume that all of the NaOH dissociates completely in water to form Na+ and OH- ions. Therefore, the concentration of hydroxide ions in the solution is also 0.001 M.

The pOH is calculated using the equation:

pOH = -log[OH-]

Substituting the concentration of hydroxide ions, we have:

pOH = -log(0.001)

Using a calculator, we can evaluate the logarithm:

pOH ≈ 3

Therefore, the pOH of the 0.001 M NaOH solution is approximately 3.

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Answer:

ATP

Explanation :

Because the energy is released during the process of glycolysis in cellular respiration and then the molecule is captured by the energy carrying molecule which is the ATP (adenosine triphosphate).

Answer:

How do amoeba respire.

how do plants respire.

b

Explanation:

containing of ion electron and protons

Potash alum, represented by the chemical formula KAl(SO4)2·12H2O, is a double salt because it consists of two different salts, potassium sulfate (K2SO4) and aluminum sulfate (Al2(SO4)3), combined together. It forms a unique crystalline structure with 12 water molecules incorporated in its composition.

Potash alum is a type of alum that is commonly used in dyeing and water purification applications. The chemical formula for alum is KAl(SO4)2·12H2O.

The term "double salt" refers to the fact that the compound is made up of two different types of ions that are combined together.
In the case of potash alum, the two different types of ions are potassium ions (K+) and aluminum ions (Al3+). These two ions are combined together in a 1:1 ratio to form a complex ion, KAl(SO4)2, which is then combined with 12 water molecules to form the final compound, KAl(SO4)2·12H2O.
The term "double salt" is used to describe this type of compound because it contains two different types of cations (positive ions) that are combined together to form a single crystal lattice structure.

The two different cations are held together by ionic bonds, which are relatively strong and help to give the compound its characteristic properties.
Potash alum is a particularly useful compound because it has a number of important properties that make it useful in a variety of applications.

For example, it is highly soluble in water, which makes it a good choice for use in water purification applications.

It is also relatively stable and non-toxic, which makes it safe to use in a variety of different settings.

Finally, it has a number of useful physical properties, such as its ability to form crystals that are highly reflective and have a characteristic octahedral shape.

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The average atomic mass of a chemical element is calculated by taking into account the atomic masses of its naturally occuring isotopes and their respective abundances.

avg. atomic mass=∑i(isotopei×abundancei)

atomic masses of four isotopes of sulphur are

32S: 31.972 u→95.002%

33S: 32.971 u→0.76%

34S: 33.967 u→4.22%

36S: 35.967 u→0.014%

the average atomic mass of sulfur will be

Average atomic mass=31.972 u×0.95002+32.971 u×0.0076+33.967 u×0.0422+35.967 u×0.00014

Average atomic mass=32.063 u

Answer:

c cells

Explanation:

learned that in 7th grade

4) The volume of the HCl used is 9.500 mL while the volume of the NaOH used is 3.800 mL.

5) Molarity of sodium hydroxide is obtained from; Molarity of HCl * 1/2

By reacting an unknown component with a known quantity of a different chemical known as a titrant, titration is a laboratory procedure used to measure the concentration of an unknown substance, often a solute dissolved in a liquid.

The endpoint of a titration can be detected in a number of ways, depending on the specific titration being performed.

4)

Volume of the Acid used = Initial reading - Final reading = 25.00 - 15.50 = 9.500 mL

Volume of the base used = 8.80 - 5.00 = 3.800 mL

5)

We know that the mole ratio is 1:2 and the implication of this is that the set up to obtain the molarity of the sodium hydroxide solution is Molarity of HCl * 1/2

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Answer:

Me!!!

Explanation:

Answer:

It is important to record the crime scene in order to view how it was originally found so when items are removed, it can still be investigated and viewed.

Explanation:

the ph is gonna be your value and the 4 is gonna be your main subject

so as the ph is your value u gonna ad your ph and 7 and 4 toghter then multiple your answer 2 times  because ph represent multiple and your value  

Answer:

The concentration would be 0.76 mol/L.

The most common way to solve this problem is to use the formula

c1V1=c2V2

In your problem,

c1 = 4.2 mol/L; V1 = 45.0 mL

c2 = ?; V2 = 250 mL

c2=c1×V1V2 = 4.2 mol/L × 45.0mL250mL = 0.76 mol/L

This makes sense. You are increasing the volume by a factor of about 6, so the concentration should be about ¹/₆ of the original (¹/₆ × 4.2 = 0.7).

Explanation:

if it is helpful...... plzz like and follow

Answer:

Velocity

Explanation:

Synonyms are words/phrases that mean the exact or nearly exact same in meaning. Velocity, pace, and speed all mean close to the same thing as far as the rate in which something is moving.

Answer:

B 1650

Explanation:

Answer: (give brainliest)

( )weight

Explanation:

You would have the same mass on Mars or Jupiter as you do here on Earth. Your weight is different on other planets due to gravity. However, your mass is the same everywhere!

Answer:

Density

Explanation:

The body of scientific knowledge is based on different Observations (Option C).

Observations in the scientific method are fundamental because it is the first step to raising scientific questions that may be explained through plausible hypotheses. Subsequently, hypotheses must be tested by experimental procedures.

In conclusion, the body of scientific knowledge is based on different Observations (Option C).

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Answer: Temperature = T, unknown

Saturated Solution, NH4Cl concentration = 60g/100g H2O = 0.6g NH4Cl/g H2O

Assume density of H2O = 1 g/ml

m = 0.6g NH4Cl/g H2O / 1 g/ml

m = 0.6g NH4Cl/ml

See the table of saturated solutions and identify the temperature at which the concentration of NH4Cl is 60g/100g H2O.

Explanation:  The line on the graph on reference table G indicates a saturated solution of NH4CL as a concentration of 60. g NH4 Cl/100. g H2O

Answer:

the metal melts and floats

Explanation:

When potassium is added to water, the metal melts and floats. It moves around very quickly on the surface of the water. The hydrogen ignites instantly. The metal is also set on fire, with sparks and a lilac flame.

Answer:

It reacts rapidly to form a colorless solution of potassium hydroxide.

Explanation:

Potassium metal reacts very rapidly with water to form a colorless basic solution of potassium hydroxide (KOH) and hydrogen gas (H 2). The reaction continues even when the solution becomes basic. The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic.

The percent composition of CuBr₂ is approximately 28.46% of Cu and 71.54% of Br.

To determine the percent composition of CuBr₂ (copper(II) bromide), we need to calculate the mass of each element in the compound and then divide it by the molar mass of the entire compound.

The molar mass of CuBr₂ can be calculated by adding up the atomic masses of copper (Cu) and bromine (Br) in the compound. The atomic masses of Cu and Br are approximately 63.55 g/mol and 79.90 g/mol, respectively.

Molar mass of CuBr₂ = (63.55 g/mol) + 2(79.90 g/mol) = 223.35 g/mol

Now, let's calculate the percent composition of each element in CuBr₂:

Percent composition of copper (Cu):

Mass of Cu = (63.55 g/mol) / 223.35 g/mol × 100% ≈ 28.46%

Percent composition of bromine (Br):

Mass of Br = 2(79.90 g/mol) / 223.35 g/mol × 100% ≈ 71.54%

Therefore, the percent composition of CuBr₂ is approximately:

- Copper (Cu): 28.46%

- Bromine (Br): 71.54%

These values represent the relative mass percentages of copper and bromine in the compound CuBr₂.

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The element will lose electrons to become stable if the valence shell contains 3 or fewer electrons. The production of cations is a sign of electron loss. The species having positive charge are called cations. As a result, the ion will get a positive charge.

An atom or molecule with a net electrical charge is known as an ion. Conventionally, the charge of an electron is thought to be negative; this charge is equal to and opposite to the charge of a proton, which is thought to be positive.

An atom will shed its valence electrons in order to become a charged ion and create an ionic bond with another atom if it lacks one to three of them.

A positive ion is created by taking electrons from a neutral atom, whereas a negative ion is created by adding electrons to a neutral atom. The quantity of protons remains constant during the formation of an ion.

Thus, the ion will get a positive charge.

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add it up maybe?

Explanation:

The atomic mass of any element can be easily determined with the help of the number of protons and neutrons. You are simply required to add the number of neutrons and protons in order to estimate the atomic mass of any element.

The Atomic mass of an element may be defined as the average mass of the atoms of an element that are significantly measured in the atomic mass unit (amu).

Another method through which you can approximate the value of the atomic mass of any element is that you are simply required to double the value of the atomic number that is known for each specific element.

For example, The atomic number of oxygen is 8, while its atomic mass is 8 × 2 = 16. Similarly, the atomic number of nitrogen is 7, while its atomic mass is 7 × 2 = 14.

Therefore, it is well described above.

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Given that a single-displacement reaction occurred between two (2) reactants which were placed into a flask,  the potential identities of A, B, and X are: D. A = Mg, B = O, X = Cl.

A single-displacement reaction is also referred to as a single-replacement reaction and it can be defined as a type of chemical reaction wherein a single (one) chemical element of the reacting chemical compound is displaced (replaced) by a similar chemical element.

This ultimately implies that, a single-displacement reaction typically involves a single element displacing another chemical element within a chemical compound.

Note: A potential identity reveals the chemical symbol or name of a chemical element in a particular chemical reaction.

Given the following general reaction of scheme of:

                                     \(2AB+2X_2\rightarrow 2AX_2+B_2\)

We would proceed to replace the variables with chemical elements as follows:

                                    \(2MgO+2Cl_2\rightarrow 2MgCl_2+O_2\)

Therefore, the potential identities of A, B, and X are:

\(A = Mg\\\\B = O\\\\X = Cl\)

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PS: Your question is lacking the necessary information, but I have provided them in the image attached.

Answer:

Explanation:

sory i dont know