1. Formic acid, HFor, has a Ka value of 1.8x10-4.
a) What is the pH range of a formic acid (HFor) - sodium formate (NaFor) buffer system?​

Answer:

Chemistry is the study of matter and energy and the interactions between them. You could use chemistry in most fields, but it's commonly seen in the sciences and in medicine.Chemists, physicists, biologists, and engineers study chemistry.

Explanation:

Answer:

Chemistry is a branch of study which deals with matter.

Explanation:

All matter is made up of atoms which undergoes chemical reactions.

Chemistry is the study which deals with these chemical reactions.

The physical and chemical properties gives us the information about the nature of the substance.

We get to know the composition and structure of various compounds present in nature.

Analytical chemistry, biochemistry, inorganic chemistry, organic chemistry, physical chemistry, and biophysical chemistry are some of the important branches of chemistry.

Analytical chemistry uses qualitative and quantitative observation to identify and measure the physical and chemical properties of substances

Physical chemistry combines chemistry with physics. Physical chemists study how matter and energy interact.

Organic chemistry is known as the “Chemistry of Life” because all of the molecules that make up living tissue have carbon as part of their makeup.

Inorganic chemistry studies materials such as metals and gases that do not have carbon as part of their makeup.

Biochemistry is the study of chemical processes that occur within living organisms.

There will be only one solution for the angle. So, the correct option is D.

SSA or side-side-angle, triangle is a combination of triangles, where the length of two of the sides and the non-included angle between the two sides is known.

Here,

In SSA triangle, length of two sides and one angle will be known.

It is given that the length of the two sides is equal. Therefore the angles opposite to these sides will also be equal. Let the angle be x.

If the sides are equal, according to trigonometry, the non-included angle will be equal to 45°.

So, we can write that,

The sum of the angles,

45° + x + x = 180°

2x = 135

Therefore, x = 67.5°

Hence,

There will be only one solution for the angle. So, the correct option is D.

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Answer:

change of state

Explanation:

chemical change is a permanent change

The choices that best indicate that a substance has experienced a chemical change are

1. When the substance changes temperature

2. when the substance changes shape

4. when a new substance is formed

A chemical change is a change that happens after a chemical reaction. These changes are changes in the shape, structure, or pH of the substance.

When two substances join together to form a new compound or substance. Then it is a chemical change. The volume will not change in the chemical change because the volume the reactant has will be the same as the product.

The temperature change is a chemical change and when the substance changes its shape. It is a chemical change when wood burns and changes into coal or ash.

Thus, the correct options are  1, 2, and 4.

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The question is incomplete. Your most probably complete question is given below:

Select all that apply.

Answer:

Approximately 206 grams.

Explanation:

How many moles of sulfuric acid [tex]\mathrm{H_2SO_4}[/tex] are there in this solution?

[tex]\text{Number of moles of solute} = \text{Concentration} \times \text{Volume}[/tex].

The unit for concentration "[tex]\mathrm{M}[/tex]" is equivalent to mole per liter. In other words, [tex]\rm 1\;M = 1\; mol\cdot L^{-1}[/tex]. For this solution, the concentration of [tex]\mathrm{H_2SO_4}[/tex] is [tex]\rm 0.420\;M = 0.420\; mol\cdot L^{-1}[/tex].

[tex]\begin{aligned}n(\mathrm{H_2SO_4}) &= c(\mathrm{H_2SO_4}) \cdot V\\&= \rm 0.420\;mol\cdot L^{-1}\times 5.00\; L \\&= \rm 2.10\; mol\end{aligned}[/tex].

What's the mass of that [tex]\rm 2.10\; mol[/tex] of [tex]\mathrm{H_2SO_4}[/tex]?

Start by finding the molar mass [tex]M[/tex] of [tex]\mathrm{H_2SO_4}[/tex].

Relative atomic mass data from a modern periodic table:

[tex]\displaystyle M(\mathrm{H_2SO_4}) = 2\times \underbrace{1.008}_{\mathrm{H}} + 1\times \underbrace{32.06}_{\mathrm{S}} + 4\times \underbrace{15.999}_{\mathrm{O}} = \rm 98.072\;g\cdot mol^{-1}[/tex].

[tex]\text{Mass} = \text{Quantity in moles} \times \text{Molar Mass}[/tex].

[tex]m = n \cdot M = \rm 2.10\; mol \times 98.072\;g\cdot mol^{-1} \approx 206\; g[/tex].

In other words, the chemist shall need approximately 206 grams of [tex]\mathrm{H_2SO_4}[/tex] to make this solution. As a side note, keep in mind that the 206 grams of [tex]\mathrm{H_2SO_4}[/tex] also take up considerable amount of space. Therefore it will take less than 5.00 L of water to make the 5.00 L solution.

Answer:

Explanation

=============

One

=============

Ca(OH)2 + 2HNO3 -----> Ca(NO3)2 + H2O

Focus on the NO3. This is an odd problem and you usually do not focus on the complex ion. But this one works easiest if you do.

The problem now is going to be the oxygens. There are 2 with the Calcium and only 1 free one going to the water. (The NO3 has been taken care of in the last step).

Ca(OH)2 + 2HNO3 -----> Ca(NO3)2 + 2H2O

Count the atoms. I think this equation is balanced.

atom                      Left              Right         Result

Ca                            1                    1               Balanced

O                              8                   8              Balanced

H                              2 + 2              2*2         Balanced

N                               2                    2            Balanced

===========

Two

===========

CH4 + O2====>  CO2 + H2O

Start with the hydrogens.

The right side requires a 2

CH4 + O2 ===>  CO2 + 2H2O

Now look at the oxygens. There are 4 on the right. and only 2 on the left. You need to multiply O2 by 2

CH4 + 2O2 ===>  CO2 + 2H2O

Each side has 1 Carbon 4 hydrogens and 4 oxygens. The equation is balanced.

14.7 g of chromium are need to produce 27.0 g of copper in the reaction:

2 Cr + 3 CuSO4 → Cr2(SO4)3 + 3 Cu. In this reaction, chromium is the limiting reactant and CuSO4 is the excess reactant.

Further Explanation:

The problem given is an example of a stoichiometry problem. Stoichiometry involves the determination of the amounts of products formed and amount of reactants consumed in a chemical reaction. It uses the ratio of the reactants and products given by the balanced chemical equation.

Limiting reactant is the reactant that determines how much of the product(s) will be obtained. In this problem, chromium is the limiting reactant.

To solve the amount of limiting reactant we use several steps:

STEP 1: Convert mass to moles using the equation below:

[tex]no. \ of \ moles \ = given \ mass \ (\frac{1 \ mole}{molar \ mass})[/tex]

For this problem,

[tex]no. \ of \ moles \ Cu \ = 27.0 \ g \ Cu \ (\frac{1 \ mole \ Cu}{ 63.55 \ g}) \\\boxed {no. \ of \ moles \ Cu \ = 0.4249}[/tex]

STEP 2: Calculate the number of moles of Cr used up using the stoichiometric ratio from the balanced equation: 3 moles Cu: 2 moles Cr

[tex]moles \ of \ Cr \ = given \ moles \ Cu (\frac{2 \ mol \ Cr}{3 \ mol \ Cu})\\moles \ of \ Cr \ = \ 0.4249\ mol\ Cu (\frac{2 \ mol \ Cr}{3 \ mol \ Cu})\\ \\\boxed {moles \ of \ Cr \ = \ 0.2832 }[/tex]

STEP 3: Convert moles of Cr to mass (in grams).

[tex]mass \ = given \ moles \ (\frac{molar \ mass}{1 \ mole})\\[/tex]

To get the mass of Cr,

[tex]mass \ of \ Cr \ = 0.2832 \ mol \ (\frac{52.00 \ g}{1 \ mol})\\\boxed {mass \ of \ Cr \ = 14.7 \ g}[/tex]

Learn More

Keywords: excess reactant, limiting reactant

The mass of chromium, Cr needed to react with excess CuSO₄ to produce 27 g of Cu is 14.7 g

2Cr + 3CuSO₄ → Cr₂(SO₄)₃ + 3Cu

Molar mass of Cu = 52 g/mole

Mass of Cr from the balanced equation = 2 × 52 = 104 g

Molar mass of Cu = 63.5 g/mole

Mass of Cu from the balanced equation = 3 × 63.5 = 190.5 g

SUMMARY

From the balanced equation above,

190.5 g of Cu were produced from 104 g of Cr

From the balanced equation above,

190.5 g of Cu were produced from 104 g of Cr

Therefore,

27 g of Cu will be produce by = (27 × 104) / 190.5 = 14.7 g of Cr

Thus, 14.7 g of Cr is needed for the reaction

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Answer:

The following reaction shows the production of hydrogen gas from water. This chemical reaction should be classified as decomposition ( second choice)

Answer:

B. Decomposition

Explanation:

[tex]2 H_2 O>2H_2+O_2[/tex]

Decomposition is the type of reaction in which a compound is broken into smaller  compounds or broken into its elements

[tex]AB>A+B\\\\CaCO_3>CaO+CO_2[/tex]

Synthesis is just opposite to decomposition reaction, Elements combine to form a compound

[tex]A+B>AB\\\\CaO+CO_2>CaCO_3[/tex]

Single replacement reactions in which replacement takes place at a single place

[tex]A+BC>AB+C\\\\Zn(s)+CuCl_2 (aq)>ZnCl_2 (aq)+Cu(s)[/tex]

Double replacement reactions in which replacement occurs two places

[tex]AB+CD>AD+BC\\\\AgNO_3+NaCl>AgCl+NaNO_3[/tex]

Neutralization reaction is the reaction between an acid and a base to form salt and water

[tex]HCl+NaOH>NaCl+H_2 O[/tex]

The volume of carbon dioxide gas changes from 6.75 L to b) 10.7 L when the pressure is decreased from 175 atm to 110 atm, as per Boyle's Law.

The student asks how the volume of carbon dioxide gas changes when the pressure is decreased from 175 atm to 110 atm, assuming constant temperature and number of gas particles. This is a classic application of Boyle's Law in the study of gas laws, which can be expressed in the equation P1V1 = P2V2, where P1 and V1 are the initial pressure and volume, and P2 and V2 are the final pressure and volume respectively. Given the initial conditions (P1 = 175 atm and V1 = 6.75 L) and final pressure (P2 = 110 atm), we can solve for the new volume V2.

Using Boyle's Law:

Therefore, the new volume is b)  10.7 L when the pressure is decreased to 110 atm.

Answer:is it correct

Explanation:

Answer:

C.  The total mass of sodium chloride and water formed is greater than 35 grams.

Explanation:

I took the test and got it right

Answer:

B. 387 V

Explanation:

Ohm's law states that the voltage is the product of the current and resistance.

V = IR

V = (9 A) (43 Ω)

V = 387 V

1 mole = 6.022*10^23 atoms

So, we divide 5.22*10^22 by 6.022*10^23

Answer is 8.67*10^-2

Mole is described as the amount of the substance containing the identical wide variety of discrete entities (atoms, molecules, ions, and so forth) as there are atoms in a sample of pure 12C weighing precisely 12g. The quantity of debris present in one mole of any substance =Avogadro Number=6.

Avogadro's number is a single mole of any substance (described as its molecular weight in grams), the same as 6.02214076 × 1023.

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Answer:

Reactivity.

Explanation:

The activity series is used to determine, for example, if a single displacement reaction occurs, and that depends on the activity of the ion of an element.

Hope this helped!

Answer: Option (c) is the correct answer.

Explanation:

An activity series is defined as the series that shows metals arranged in decreasing order according to their reactivity.

Atomic mass is the sum of total number of protons and neutrons present in an atom.

Atomic radius is defined as the distance from the center of the nucleus to the outer most shell. Larger is the size of an atom, greater will be its atomic radius.

Reactivity is the ability of an atom to readily combine or react with a substance in order to gain stability.

Solubility is water means whether a compound or molecule dissociate into ions or not if dissolved in water.

Therefore, we can conclude that reactivity is the property of an element determines its position in the activity series.

Answer:

A. 2 bonds

Explanation:

If you see a charch of ci20 it would easily show the answer.

Answer:

Decrease in temperature

Addition of catalyst (Fe)

Answer:

III only

Explanation:

The rate of a chemical reaction (when reactant particles are gases) is increased by the following factors

The only correct option from the question is III

A catalyst increases the rate of chemical reaction by reducing the activation energy of the reaction. Activation energy is the minimum amount of energy required for a reaction to occur. So, when the activation energy is lowered, the time required to complete a reaction reduces, hence the rate of reaction increases.

Answer: different charges but same mass

protons and neutrons determine the mass (electrons are too light)

since atom q and atom r are of the same proton and neutron , they are of the same mass

protons and electrons determine the charge

a proton has a 1+ and electron has a 1- charge

atom q has no charge, the protons and electrons cancel each other out

atom r has a 1- charge as there is one more electron than proton.

Answer : Thecorrect option is, They have different charges and same masses.

Explanation :

As we know that an atom is the smallest unit of a matter that consist of three subatomic particles which are electrons, protons and neutrons.

The protons and the neutrons are located inside the nucleus or center of the nucleus where the mass of the an atom is concentrated and the electrons are located around the nucleus.

The protons are positively charged, the electrons are negatively charged and the neutrons are neutral that means it has no charge.

Atomic number : It is defined as the number of protons or number of electrons.

Atomic number = number of protons = number of electrons

Mass number : It is defined as the sum of number of protons and number of neutrons.

Number of neutrons = Mass number - Number of protons

From the given data we conclude that:

Atom Q has 11 number of protons, electrons and 12 number of neutrons.

Atom R has 11 number of protons, 10 number of electrons and 12 number of neutrons.

Atom Q has no charge but Atom R has (+1) charge due to loss of 1 electron. That means, they have different charges.

Mass of Atom Q = Number of neutrons + Number of protons = 11 + 12 = 23

Mass of Atom R = Number of neutrons + Number of protons = 11 + 12 = 23

Thus, the correct option is, They have different charges and same masses.

Answer:

3.89 kg P2O5 must be used to supply 1.69 kg Phosphorus to the soil.

Explanation:

The molecular mass of P2O5 is

P2 = 2* 31 =           62

O5 = 5 * 16 =         80

Molecular Mass = 142

Set up a Proportion

142 grams P2O5 supplies 62 grams of phosphorus

x    kg P2O5        supplies 1.69 kg of phosphorus

Though this might be a bit anti intuitive, you don't have to convert the units for this question. The ratio is all that is important.

142/x = 62/1.69            Cross multiply

142 * 1.69 = 62x           combine the left

239.98 = 62x               Divide by 62

239.98/62 = x

3.89 kg of P2O5 must be used.

Decomposition is a reaction in which a compound is broken down into its components. The mass of pure P2O5 is obtained by mass- mole relationship.

The equation of the decomposition of P2O5  is;

[tex]2 P2O5 -----> P4 + 5 O2[/tex]

Number of moles phosphorus supplied to the soil = [tex]\frac{1.69 * 10^3}{124 g/mol}[/tex] = 13.6 moles

From the reaction equation, we can see that;

2 moles  P2O5 yields 1 mole of phosphorus

x moles of  P2O5 yields 13.6 moles of phosphorus

x = 2 mole * 13.6 moles/ 1 mole

x = 27.2 moles

Mass of  pure P2O5 = 27.2 moles * 142 g/moles = 3862 g or 3.862 Kg

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Answer: A) Reduces friction between soil grains

Hope this helps!!! :)

Explanation:

Answer: I think that the answer is Z.

Answer:

Pb⁺²(aq) + CO₃⁻²(aq) →  PbCO₃ (s)

In net ionic equation we cancel the ions that have equal moles on both sides so  Na⁺¹ and NO₃⁻¹ have equal moles on both sides so we canceled them.

Explanation:

Net ionic equation:

In net ionic equation we only write the ions that are involved in reaction. If the system have same moles of ions in initial and final stages we cancel them as they have the same amount and are present in ionic form in the reaction medium. To formulate an ionic equation we just cancel the ions which have the same moles in initial and final stages.

Chemical equation:

Pb(NO₃)₂ (aq) + Na₂CO₃(aq) → PbCO₃ (s) + NaNO₃ (aq)

Balanced chemical equation:

In a balanced chemical equation we write the reactants and products in molecular form with number of moles.

Pb(NO₃)₂ (aq) + Na₂CO₃(aq) → PbCO₃ (s) + 2NaNO₃ (aq)

Ionic equation:

In ionic equation we write the equation in ionic form. It involves all the ions which will produce when we add any ionic compound in reaction medium.

Pb⁺² +2NO₃⁻¹ + CO₃⁻² + 2Na⁺¹  → PbCO3 (s) + 2NO₃⁻¹ (aq) + 2Na⁺¹ (aq)

Net ionic equation

In net ionic equation we cancel the ions that have equal moles on both sides. As we can see in the above ionic equation that Na⁺¹ and NO₃⁻¹ have equal moles on both sides so we canceled them.

Pb⁺²(aq) + CO₃⁻²(aq)  → PbCO₃ (s)

Answer:

The products are beyond the "yield" symbol [→] to the right.

I am joyous to help.

Answer:

D

Explanation:

The general equation for this is

F = G*m1*m2/r^2

If the distance (r) remains the same and m1 and m2 are both doubled, then the equation becomes

F1 = G * (2m1)(2m2)/r^2

F1 = 4 [G * m1 * m2)/r^2 ]

So F1 is 4 times as large as the initial Force (F)

Answer: D

When the mass of each object is doubled, the gravitational force between them becomes four times greater. Originally it is 100 N, so when each mass is doubled, the new gravitational force will be 400 N, according to Newton's law of universal gravitation.

The question is related to the gravitational force between two objects, which is directly governed by Newton's law of universal gravitation. This law states that the gravitational force (F) between two objects is directly proportional to the product of their masses (m1 and m2) and inversely proportional to the square of the distance (r) between their centers:

F = G × (m1 × m2) / r²

where G is the gravitational constant. If we double the mass of each object, the new force (F') will be:

F' = G × (2m1 × 2m2) / r² = 4 × (G × m1 × m2) / r² = 4F

Thus, the new gravitational force if the mass of each object is doubled will be four times the original force. Since the original force is given as 100 N, the new force will be:

F' = 4 × 100 N = 400 N

Therefore, the correct answer is:

d: 400 N

Answer:

The correct answer option is a. Selenium (Se).

Explanation:

From the given answer options, Selenium (Se) is the only element which is a non metal.

It has the atomic number 34 with atomic weight 78.96. It is a member of the sulfur group of the non metallic elements and falls in period 4 of the Periodic table.

Selenium has non metallic properties which are intermediate between the elements that lie above and below it in the Periodic table.

Answer:

a. Selenium

Explanation:

Selenium is a non metal but though rarely, it is considered to be a metalloid.

(Metalloids are elements intermediate between metals and nonmetals and are known to have partly metallic and partly non metallic properties.)

Selenium is in group 16 of the periodic table below sulphur and has average properties of the group elements above and below it in the periodic table..  

Answer:

True

Explanation:

The molecule CH20 contains two single bonds and one double bond.

Answer:

In a voltaic cell, the Anode Loses electrons and is oxidized, while the Cathode Gains electrons and is reduced.

Explanation:

The strongest reducing agent which is the Anode is oxidized, the Anode is negative so it loses electrons.

The strongest oxidizing agent is the Cathode, which is positive so it gains.

Also for further confirmation, I got it right on the test.

In a voltaic cell, the anode loses electrons and is oxidized, while the cathode gains electrons and is reduced. The voltaic cell operates on a redox reaction, generating current as a result of electron transfer from the anode to the cathode, driven by a potential difference or voltage.

In a voltaic cell, the anode loses electrons and is oxidized, while the cathode gains electrons and is reduced.

Understanding Voltaic Cells

A voltaic cell is an electrochemical cell that uses a spontaneous redox reaction to produce electrical energy. It is constructed from two half-cells connected by a conductive wire and a salt bridge. Each half-cell contains an electrode immersed in an electrolyte. The anode is where the oxidation reaction, or loss of electrons, takes place, making it the negative electrode. Conversely, the cathode is where the reduction reaction, or gain of electrons, occurs; thus, it is the positive electrode. The flow of electrons from the anode to the cathode through the wire generates electrical current.

The potential difference, or voltage of the cell, is determined by the difference in reduction potentials of the two half-reactions. The electrode with the higher reduction potential becomes the cathode, where reduction takes place, and the one with lower reduction potential becomes the anode, where oxidation occurs.

Understanding the functions of the anode and cathode is essential in analyzing and constructing voltaic cells, which can be used to power various electrical devices.

b.

Same because, mass doesn’t count liquid or solid

The mass of the jelly is the same as the mass of the liquid as mass is always conserved when the state of matter changes according to law of conservation of mass.

Law of conservation of mass states that the mass is neither created nor destroyed rather it is always restored during any chemical or physical change.During a chemical change, the mass of reactants is equal to the mass of products.It implies to the fact that mass does not change with time.

In the process of making jelly only physical changes are involved as there is no chemical change taking place during the process and hence the mass remains the same irrespective of the state of matter.

The law was discovered by Antoine Lavoisier in the year 1789. Concept of conservation of mass is widely used in chemistry,fluid dynamics and mechanics.

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Answer:

Concentration

Explanation:

Amount of substance concentration often called simply concentration, is a quantitative measure of the number of atom s per unit volume in a sample of a matter.

Four common properties of covalent compounds:

1. Low melting points and boiling points.

2. Lower enthalpies of fusion and vaporization.

3. More flammable.

2. Doesn't conduct electricity.

Hey there!:

Option B,CO2 at 353K

*Since most collisions means that highest kinetic energy.

*As we know that kinetic energy of gas molecules is directly proportional to absolute temperature

*More the temperature, More the kinetic energy.

* Hence B  is the correct answer as it has highest temperature.

Hope this helps!

Answer: Option (b) is the correct answer.

Explanation:

As it is known that more is the kinetic energy present between the molecules of a gas, more will be the number of collisions take place.

Also, relation between kinetic energy and temperature is as follows.

                     K.E = [tex]\frac{3}{2}kT[/tex]

This means that more is the temperature of gas more will be the kinetic energy present withing its molecules or vice-versa.

As methane is at 340 K.

Carbon dioxide is at 80 [tex]^{o}C[/tex] = (80 +273) K = 353 K

Argon is at 265 K and helium is at 20[tex]^{o}C[/tex] = (20 + 273)K = 293 K

Therefore, temperature of carbon dioxide gas is the maximum.

Thus, we can conclude that the carbon dioxide gas at 80[tex]^{o}C[/tex] will have the most collisions between its particles.