The burning of paper is an example of which type of change?
A. An atomic change
B. A chemical change
C. A physical change
D. A phase change

Answer:

1.28 M

Explanation:

Step 1: Given data

Mass of luminol (solute): 17.0 g

Volume of water: 75.0 mL (this is also the volume of solution)

Step 2: Calculate the moles corresponding to 17.0 g of luminol

The molar mass of luminol is 177.16 g/mol.

17.0 g × 1 mol/177.16 g = 0.0960 mol

Step 3: Calculate the molarity of the solution

We will use the definition of molarity

M = moles of solute / liters of solution

M = 0.0960 mol / 0.0750 L = 1.28 M

Answer:

K+ClKCl

Explanation:

because the reaction is between metal Potassium and Non-metal Chlorine

Answer:

Explanation:

a) It is a redox reaction because KCl is an ionic compounds with K having a + charge and Cl having a - charge. Originally, both have an oxidation state of 0 and not K has 1+ and Cl has 1-. Therefore, one species was oxidized and one was reduced which is indicative of a redox reactions.

b)

2K + Cl2 => 2KCl

Answer: The silver metal was OXIDIZED.

Explanation:

OXIDATION is defined as loss of electrons and increase in oxidation number of an atom.

Oxidation number is the charge on an ion in an ionic compound or the charge that an atom in a covalent compound would have it it were ionic. There are basic rules governing oxidation number, they include:

--> the oxidation number of elements in their free states is ZERO. Example O2, Cl2,Na, Al, Ag.

-->The oxidation number for an ion is the same as the size and sign of the charge on the ion. For example the oxidation number of Zn2+ is +2.

--> the sum of all the oxidation numbers of the elements in a compound is zero.

--> oxidation numbers are always written with either a positive or a negative sign.

On the other hand, reduction is the opposite of oxidation. As oxidation is taking place, reduction is also taking place. Reduction involves:

--> Gain of electron and

--> decrease in oxidation number

From the question, the silver metal had ZERO as it's oxidation number because it's in free state. After being exposed to oxygen to form silver oxide, the oxidation number became +1.

Since there is an increase in the oxidation number, the silver metal was OXIDIZED

Answer:

A) Val-Gly-Arg-Ala-Val-Lys-Ala-Gly-Phe

B) Ala-Val-Lys-Val-Gly-Arg-Ala-Gly-Phe

Explanation:

The possible sequences that could be obtained from the available dat provided are :

A) Val-Gly-Arg-Ala-Val-Lys-Ala-Gly-Phe

B) Ala-Val-Lys-Val-Gly-Arg-Ala-Gly-Phe

Trypsin is generally a catalyst  for the breakdown of proteins into smaller peptides ( during the hydrolysis of peptide bonds )  

Answer:

Refraction

Explanation:

the change in direction of waves that occurs when waves travel from one medium to another. ... Diffraction is the bending of waves around obstacles and openings. The amount of diffraction increases with increasing wavelength

Answer:

A change in direction in a wave when it passes through an opening is called diffraction.

I hope this helps

Answer:

Carbon-14

Explanation:

It is because it have 6 protons and 8 neutrons which are added together to form an atomic mass of 14.

The mass number of an isotope is the sum of the number of protons and number of neutrons hence the correct answer is carbon-14.

Isotopes are atoms of the same element that has the same number of protons but different number of neutrons.

The atomic number is the same as the number of protons in the atom. Since there are six protons in the atom, the element must be carbon.

There are eight neutrons meaning that the mass  number is 8 + 6 = 14

Therefore, the isotope is carbon-14.

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Answer:

0.0922 g

Explanation:

Number of moles of acid present = 25/1000 × 0.0981

= 0.00245 moles

Number of moles of base = 5.83/1000 × 0.104

= 0.000606 moles

Since the reaction of HCl and NaOH is 1:1

Number of moles of HCl that reacted with antacid = 0.00245 moles - 0.000606 moles

= 0.001844 moles

From the reaction;

CaCO3 + 2HCl ----> CaCl2 + H2O + CO2

1 mole of CaCO3 reacts with 2 moles of HCl

x moles of CaCO3 reacts with 0.001844 moles ofHCl

x = 1 × 0.001844/2

= 0.000922 moles

Mass of CaCO3 = 0.000922 moles × 100 g/mol

= 0.0922 g

Answer:

Because a Lone pair of electrons on nitrogen is involved in delocalization.

Hope this helps you ( ◕ᴗ◕✿)

If it doesn't i'm sorry(◞ ‸ ◟)

Explanation:

In ethylamine ethyl is electron donating group. So more electrons are available aroudn nitrogen for donation. But in aniline phenyl group is electron attracting group.

We want to find the value of t such that the velocity vector makes an angle of 45° with both axes.

We found that:

t = (2/3)*(b/c)

The velocity vector makes an angle of 45° with the x and y axes.

We know that the position vector is:

r = r=b*t²i + c*t³j

Remember that the versor "i" corresponds to the x-component, and the versor "j" corresponds to the y-component, then:

r = r=b*t²i + c*t³j  = (b*t², c*t³)

The velocity vector is the vector that we get when we differentiate the position one, remember that if:

f(x) = a*x^n

then

f'(x) = n*a*x^(n - 1)

Using this, we can find that the velocity vector is:

v = (2*b*t,  3*c*t²)

Now we want to know, when does the velocity vector make an angle of 45° with the x and y axes.

Let's think of the vector as the hypotenuse of a triangle rectangle, where the x-component is the adjacent cathetus, and the y-component is the opposite cathetus. (so the angle is measured counterclockwise from the x-axis)

We have the trigonometric equation:

tan(a) = (opposite cathetus)/(adjacent cathetus)

So now we can replace these things with the known ones:

a = 45°

opposite cathetus = y-component = 3*c*t²

adjacent cathetus = x-component = 2*b*t

So we will get:

tan(45°)  =  (3*c*t²)/( 2*b*t)

1 = (3/2)*(c/b)*t

Now we can solve this for the variable, t.

1*(2/3)*(b/c) = t

t = (2/3)*(b/c)

We can conclude that at the time:

t = (2/3)*(b/c)

The velocity vector makes an angle of 45° with the x and y axes.

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Answer:

a) Freezing and condensation

Explanation:

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Answer:

1.0188 J/g*C

Explanation:

Using the formula; Q = m × c × ∆T

Q(water) = -Q(metal)

m × c × ∆T (water) = -{m × c × ∆T (metal)}

According to this question,

mass of metal = 25g

initial temp of metal = 99°C

mass of water = 50g

initial temp of water = 10.55°C

final temperature of the system = 20.15°C

c of water = 4.184 J/g*C

50 × 4.184 × (20.15 - 10.55) = 25 × c × (20.15 - 99)

209.2 × 9.6 = 25c × -78.85

2008.32 = -1971.25c

c = 2008.32 ÷ 1971.25

c of metal = 1.0188 J/g*C

Answer:

1/2 the distance

Explanation:

If the viscosity of a solution is quadrupled then the distance of collection of diffusing molecules would be half over the same amount of time. The viscosity of the molecules is dependent on density of the liquid. It is independent to the volume of the liquid.

Explanation:

The given data is:

The half-life of gentamicin is 1.5 hrs.

The reaction follows first-order kinetics.

The initial concentration of the reactants is 8.4 x 10-5 M.

The concentration of reactant after 8 hrs can be calculated as shown below:

The formula of the half-life of the first-order reaction is:

[tex]k=\frac{0.693}{t_1_/_2}[/tex]

Where k = rate constant

t1/2=half-life

So, the rate constant k value is:

[tex]k=\frac{0.693}{1.5 hrs}[/tex]

The expression for the rate constant is :

[tex]k=\frac{2.303}{t} log \frac{initial concentration}{concentration after time "t"}[/tex]

Substitute the given values and the k value in this formula to get the concentration of the reactant after time 8 hrs is shown below:

[tex]\frac{0.693}{1.5 hrs} =\frac{2.303}{8 hrs} x log \frac{8.4x10^-^5}{y} \\ log \frac{8.4x10^-^5}{y} =1.604\\\frac{8.4x10^-^5}{y}=10^1^.^6^0^4\\\frac{8.4x10^-^5}{y}=40.18\\y=\frac{8.4x10^-^5}{40.18} \\=>y=2.09x10^-^6[/tex]

Answer: The concentration of reactant remains after 8 hours is 2.09x10^-6M.

Answer:

the answer is C

Explanation:

a molecule can be made up of two atoms of the same kind, as when two oxygen atoms bind together to make an oxygen molecule

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Answer:

I'll see it

Explanation:

Answer:

There are many reagents.

1. Use acidified potassium permanganate solution

2. Use acidified potassium dichromate solution

3. Fehling solution.

4. Silver/ oxygen at 500°C

5. Copper/ oxygen at 300°C

6. Lucas reagent ( anhydrous zinc and conc. hydrochloric acid)

Explanation:

Observations:

[with acidified potassium permanganate solution]

» Ethanol : The purple solution turns colourless.

» 2-methyl-2-propanol : no observable change.

[with acidified potassium dichromate solution]

» Ethanol : orange solution turns green

» 2-methyl-2-propanol : no observable change.

[Fehling solution]

» Ethanol : a white precipitate is formed

» 2-methyl-2-propanol : no observable change

Explanation:

here's the answer to your question

Answer:

pH of buffer solution is 7.0

Initial pH of Weak acid is 3.27

Final pH of weak acid is 3.07

Amount of NaOH added is 1ml

Explanation:

Titration is a process in which acid and base are introduced together until a neutral solution is achieved whose pH value is near to buffer solution which is 7.0, the pH value for acid is below 7 while pH value for base is above 7.

The question is incomplete, the complete question is shown in the image attached to this answer

Answer:

2,3,3-trimethylhexane

Explanation:

IUPAC nomenclature provides a universally acceptable method of naming organic compounds from its structure.

According to this system of nomenclature;

A comma is used to separate two numbers.

A hyphen is used to separate a number from a letter.

Applying these rules, the name of the compound shown in the question should be written as 2,3,3-trimethylhexane.

Answer

Accordingly the order of electronegativity of the given elements would be: Fluorine > Chlorine > Bromine > Iodine. ( Fluorine has the highest electronegativity.)

Answer:

"[Temperature is a measurement of the average kinetic energy of the molecules in an object or a system. Kinetic energy is the energy that an object has because of its motion. The molecules in a substance have a range of kinetic energies because they don't all move at the same speed.]"

Answer:

Temperature is directly proportional to the average translational kinetic energy of molecules in an ideal gas

Explanation:

Answer:

smallest mass necessary to

Explanation:

The critical mass for a fissionable material is the smallest and the lowest quantity of a particular fissile material required to generate a self-sustaining fission chain reaction under specified conditions. The size's features are determined by a number of variables. Examples include;

The type of fissile material employed, its purity as well as concentration, the shape of the surrounding reaction system e.t.c.

Answer:

Fill in the blanks with the terms that complete the sentences about nuclear power plants.

Without a critical mass of fissionable material, a nuclear reaction cannot be sustained. The turbine is powered by steam.

Explanation:

The answers to both parts are marked in bold. I just answered these questions on Edge and they were both correct. Hope this helps. Please mark my answers as the brainiest. THANK YOU!!!!!!!!!!!!!!!!!!!

Calories, we know that fat burn is calories.

Answer:

See explanation and image attached

Explanation:

My aim is to convert 1-bromobutane to butanal. The first step is to react the 1-bromobutane substrate with water. This reaction occurs by SN2 mechanism to yield 1-butanol. Hence reagent A is water.

1-butanol is now reacted with an oxidizing agent such as acidified K2Cr2O7 (reagent B) to yield butanal. Note that primary alkanols are oxidized to alkanals.

These sequence of reactions are shown in the image attached.

Answer:

0.3323

Explanation:

GIven that:

Density of the metal = 10.6 g/cm^3

atomic weight = 176.8 g/mol

atmic radius = 0.130 nm

values of a and c = 0.570 nm and 0.341 nm respectively

For us to determine the atomic packing factor, we need to first determine the volume of all spheres (Vs) and the volume of unit cell (Vc).

However, the number of atoms  in the unit cell (n) can be computed as:

[tex]n = \dfrac{\rho * V_c *N_A}{A} \\ \\ n = \dfrac{(10.6) * (5.7)^2 (3.41)*(10^{-24}) *(6.022*10^{23})}{176.8}[/tex]

n = 4.0

Thus, the number of atoms in the unit cell is 4

∴

The atomic paking factor (APF) is calculated by using the formula:

[tex]\dfrac{Vs}{Vc} = \dfrac{4 * \dfrac{4}{3}\pi *R^3 }{a^2 *c} \\ \\ \\ \dfrac{Vs}{Vc} = \dfrac{4 * \dfrac{4}{3}\pi *(1.30*10^{-8})^3 }{(5.70*10^{-8})^2 *(3.41*10^{-8})}[/tex]

= 0.3323

Answer:

48.67 seconds

Explanation:

From;

1/[A] = kt + 1/[A]o

[A] = concentration at time t

t= time taken

k= rate constant

[A]o = initial concentration

Since [A] =[A]o - 0.75[A]o

[A] = 0.056 M - 0.042 M

[A] = 0.014 M

1/0.014 = (1.1t) + 1/0.056

71.4 - 17.86 = 1.1t

53.54 = 1.1t

t= 53.54/1.1

t= 48.67 seconds

Hence,it takes 48.67 seconds to decompose.

The relative atomic mass of dihydrogen monoxide is 18g/mol

According to the periodic table:

Where; H = 1g/mol and O = 16g/mol

H2O = 1(2) + 16

= 2 + 16

= 18g/mol

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The third quantum number (m) describes the specific orbital within a sublevel. The correct answer is option D.

Quantum numbers are a set of four numbers that describe the properties of an electron in an atom. They specify the energy, position, and orientation of an electron in an atom.

The third quantum number (m) is also called the magnetic quantum number. It describes the orientation of the orbital in space. Each orbital within a sublevel has a different orientation in space, and the magnetic quantum number tells us which orbital we are talking about.

The value of m can range from -l to +l, where l is the second quantum number (the angular momentum quantum number). The value of l determines the number of orbitals in a sublevel, and the value of m determines the specific orbital within that sublevel.

In conclusion, the third quantum number (m) describes the specific orbital within a sublevel. It tells us how the orbital is oriented in space, and it can have values ranging from[tex]\rm -l \ to +l[/tex], where l is the second quantum number.

Option D is the correct answer.

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