PLEASE HURRRYYYY

A buffer is made using HCO2Na. Which other substance should the buffer contain?

HCO2Li

HCO2H

NaNO3

HCl

Answer:

10

Explanation:

Answer: 10 neutrons

This isotope of fluorine has 9 protons, 9 electrons and 10 neutrons.

Explanation:

Answer:

parallel to

Explanation:

In parallel direction the air particles vibrate with respect to the direction the sound wave travels. The correct option is B.

A sound wave is the pattern of disturbance caused by the movement of energy as it propagates away from the source of the sound through a medium (such as air, water, or any other liquid or solid matter).

Sound waves are produced by object vibrations and pressure waves, such as a ringing cellphone.

Because sound waves are produced by compressions and rarefactions in the air, they are referred to as longitudinal waves. The air particles vibrate in a direction parallel to the propagation direction.

The particles in a longitudinal wave are displaced parallel to the direction of the wave. Compressions moving along a slinky are an example of longitudinal waves.

Air particles vibrate in a parallel direction to the direction of travel of the sound wave.

Thus, the correct option is B.

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Answer : The correct option is (b) 2, 3, and 6

Explanation :

Combustion reactions: It is defined as the reactions in which a hydrocarbon reacts with oxygen gas to produce carbon dioxide and water.

A balanced chemical equation is defined as the equation in which total number of individual atoms on the reactant side is equal to the total number of individual atoms on product side.

The general chemical equation for the combustion is as follows:

[tex]C_xH_yO_z+O_2\rightarrow CO_2+H_2O[/tex]

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

The reactants and products in the same combustion reaction are [tex]O_2[/tex] and [tex]CO_2,H_2O[/tex] respectively.

Hence, the correct option is (b) 2, 3, and 6

Answer:

Electrical Energy

Explanation:

There are a variety of chemical and mechanical devices that are called batteries, although they operate on different physical principles. A battery for the purposes of this explanation will be a device that can store energy in a chemical form and convert that stored chemical energy into electrical energy when needed.

Answer:

262 ppm of Na₃PO₄

Explanation:

In a dilution, the concentration of the initial solution is decreased. When you take 5.00mL of the solution that is diluted to 25.0mL The solution is diluted 25/5 = 5 times

If you make another two serial dilutions the final solution wil decrease its concentration 5*5*5 = 125 times

As original solution containing 0.200 M of Na3PO4, the final solution will have a concentration of:

0.200M / 125 = 1.6x10⁻³M

Molarity is defined as the ratio between moles and liters. 1.6x10⁻³ moles of Na3PO4 in 1L are:

1.6x10⁻³mol ₓ (164g/mol) = 0.262g Na₃PO₄ / L

Assuming density of Na3PO4 as 1g/mL the concentration of the solution is:

0.262mL Na₃PO₄ / L

As 1mL = 1000μL:

262μL Na₃PO₄ / L

μL of solute per L of solution is equal to ppm, that means the solution has:

Answer:

98 g

Explanation:

Start with the balanced equation. Then, make a little chart under the equation showing the information you have and need.

        3O₂(g) + 4Al(s)  →  2Al₂O₃(s)

m        ?           110 g

M      ___       ____

n       ___ <=  ____

"m" is for mass. "M" is for molar mass (some teachers use "MM"). "n" is for the number of moles.

To find the mass of oxygen:

To find molar mass, use the atomic mass on your periodic table. For each atom of an element, add on its atomic mass.

Molar mass of aluminum (one Al atom):

[tex]M_{Al} = 26.982 g/mol[/tex]

Molar mass of oxygen (two O atoms):

[tex]M_{O_{2}} = 16.000g/mol+16.000g/mol[/tex]

[tex]= 32.000g/mol[/tex]

Update the chart:

               3O₂(g)       +          4Al(s)          →     2Al₂O₃(s)

m                ?                        110 g

M      32.000 g/mol       26.982 g/mol

n                ___         <=      ____

Find the moles of aluminum

[tex]n_{Al} = \frac{110g}{1} *\frac{1mol}{26.982g}[/tex]    Multiply mass by molar mass to find moles.

[tex]n_{Al} = \frac{110}{1} *\frac{1mol}{26.982}[/tex]       The units "g" cancel out.

[tex]n_{Al} = 4.0(7)mol[/tex]        Keep one extra significant figure. (110 has 2 sig. figs.)

               3O₂(g)       +          4Al(s)          →     2Al₂O₃(s)

m                ?                        110 g

M      32.000 g/mol       26.982 g/mol

n                ___         <=   4.0(7) mol

Find the moles of oxygen using the mole ratio, which comes from the coefficients in the balanced equation.

The mole ratio of oxygen to aluminum is 3 to 4.

[tex]n_{O_{2}} = \frac{4.0(7)mol_{Al}}{1}*\frac{3mol_{O2}}{4mol_{Al}}[/tex]     Multiply moles of aluminum by the mole ratio.

[tex]n_{O_{2}} = \frac{4.0(7)}{1}*\frac{3mol_{O2}}{4}[/tex]             "molAl" units cancel out.

[tex]n_{O_{2}} = 3.0(52)mol_{O2}[/tex]              Keep two sig. figs. when the first is a "5"

               3O₂(g)       +          4Al(s)          →     2Al₂O₃(s)

m                ?                        110 g

M      32.000 g/mol       26.982 g/mol

n          3.0(52) mol   <=    4.0(7) mol

Find the mass of oxygen

[tex]m_{O_{2}} = \frac{3.0(52)mol}{1}*\frac{32.000g}{1mol}[/tex]        Multiply moles by molar mass.

[tex]m_{O_{2}} = \frac{3.0(52)}{1}*\frac{32.000g}{1}[/tex]             The "mol" unit cancels out.

[tex]m_{O_{2}} = 97.(6)g[/tex]                         Keep one sig. fig. to round. "6" rounds up.

[tex]m_{O_{2}} = 98g[/tex]                               <= Final answer

∴ 98 grams of oxygen are required to completely react with 110 grams of aluminum.

Answer:

B

Explanation:

Oxidation

Zn---> Zn2+ 2e

Reduction

Cu2+ + 2e ---->Cu

Answer:

a.calcium

b.chlorine

Answer:

Neutron

Explanation:

Answer:

IL

Explanation:

M_1 V_1 = M_2 V_2

M_1 = 15 M

V_1 = 0.2 L

M_2 = 3 M

V_2 = ?

15 x 0.2 = 3V_2

15 x 0.2 = 3

3 / 3V_2

1 L= V_2

1 L is the volume that would be needed to dilute 0.2 L of a 15 M solution to obtain a 3 M solution.

A measurement of three-dimensional space is volume. It is frequently expressed quantitatively in SI-derived units, other imperial units, or US customary units. Volume and the notion of length are connected. In contrast to how much space the container actually occupies, the overall size of a container is typically thought of as its capacity, or the quantity of fluid it could hold.

Volume was initially measured using naturally occurring vessels of a comparable shape and then with standardised containers. Arithmetic formulas can be used to quickly calculate the volume of several straightforward three-dimensional shapes.

Molarity₁×Volume₁=Molarity₂×Volume₂

15 x 0.2 = 3×Volume₂

15 x 0.2 = 3

3 / 3=Volume₂

1 L=Volume₂

Therefore, 1 L is the volume that would be needed to dilute 0.2 L of a 15 M solution to obtain a 3 M solution.

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Answer:

Bcinder

Explanation:

Answer:

b

Explanation:

edge 2021

According to the concept of conduction,heat  flows from faster molecules to slower molecules when they collide.

Conduction is defined as a process as a means of which heat is transferred from the hotter end of the body to it's cooler end.Heat flows spontaneously from a body which is hot to a body which is cold.

In the process of conduction,heat flow is within the body and through itself.In solids the conduction of heat is due to the vibrations and collisions of molecules .

There are 2 types of conduction:1) steady state conduction 2) transient conduction.According to the type of energy conduction is of three types:

1) heat conduction

2) electrical conduction

3)sound conduction

Heat is transferred from faster to slower molecules when they collide , thus the correct option is that heat flows from faster molecules to slower molecules when they collide.

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Answer: (1) Hydroxide ion

Explanation: Because LiOH is a base hydroxide ion is OH-

The answer is hydroxide ion.

Using this equation, we find the pH of pure water to be 7. This is considered to be neutral on the pH scale. The pH can either go up or down depending on the change in hydronium concentration. If the hydronium concentration increases, the pH decreases, causing the solution to become more acidic.

When an excess base is dissolved in a solution of sodium hydroxide. Sodium hydroxide dissociates into OH- ions and when the number of OH- increases then concentration also increases because concentration is the number of OH- ions present per unit volume.

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Answer:

About 164 grams

Explanation:

The molecular formula of calcium nitrate is [tex]Ca(NO_3)_2[/tex]. The molar mass of calcium is about 40, while the molar mass of nitrogen is about 14 and oxygen is about 16. Therefore, the molar mass of it is:

[tex]40+2(14+3(16))=40+2(14+48)=40+124=164[/tex]

Hope this helps!

Dependent variables receive this name because, in an experiment, their values are studied under the supposition. The dependent variable is the cleanliness of the clothes.

It is something on which other elements depend. A test score, for instance, may be a dependent variable because it could vary based on a number of variables, including how much you studied, how much sleep you got the night before the test, and even how hungry you were.

A dependent variable is one that is altered as a result of the modification of an independent variable. Your independent variable "depends" on the outcome you're interested in measuring. Dependent variables are also referred to as: response elements (they respond to a change in another variable)

There are often two different sorts of variables in analytical health research. We anticipate that independent variables will have an impact on dependent variables.

Thus,The dependent variable is the cleanliness of the clothes.

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Answer:

Option B. Keq = [CO2] [CaO]/ [CaCO3]

Explanation:

The balanced equation for the reaction is given below:

CaCO3(s) —> CaO(s) + CO2(g)

The expression for the equilibrium constant, Keq is simply the ratio of the concentration of the products to that of the reactants.

The expression for the equilibrium constant, Keq is given below:

Keq = [CO2] [CaO] / [CaCO3]

Answer: c) Keq= [co2]

Explanation:

edge 2023

bromine is used to distinguish between saturated and unsaturated compounds. when bromine water is added to the unsaturated compound, bromine that added to the unsaturated compound and the red brown colour of bromine water is discharged.

Answer: cation

Explanation:

"A" represent in a cation in the standard form of a double replacement reaction. Therefore, option B is correct.

Positively charged ions are known as cations. Negatively charged ions are known as anions. Ions are positively or negatively charged atoms or molecules. A balanced atom will become a positively charged cation if one or more electrons are lost.

In an electrical field, these ions are known as "cations" because they are positively charged and migrate toward the negative electrode (cathode).

The double-replacement reaction generally take up the form of AB + CD → AD + CB where A and C are positively-charged cations and B and D are negatively-charged anions.

Thus, option B is correct.

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Answer:

About 96 grams per mole

Explanation:

The chemical formula of ammonium carbonate is [tex](NH_4)_2CO_3[/tex]. This means that breakdown of moles of atom per mole of molecule is:

2 moles of nitrogen, with a molar mass of around 14

8 moles of hydrogen, with a molar mass of around 1

1 mole of carbon, with a molar mass of about 12

3 moles of oxygen, with a molar mass of about 16

The molar mass of ammonium carbonate is therefore:

2(14)+8(1)+1(12)+3(16)=28+8+12+48=about 96

Hope this helps!

Answer:

2.56 grams of H₂S is needed to produce 18.00g of PbS if the H2S is reacted with an  excess (unlimited) supply of Pb(CH₃COO)₂

Explanation:

The balanced reaction is:

Pb(CH₃COO)₂ + H₂S → 2 CH₃COOH + PbS

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction) they react and produce:

In this case,  to know how many grams of H₂S are needed to produce 18.00 g of PbS, it is first necessary to know the molar mass of the compounds H₂S and PbS and then to know how much it reacts by stoichiometry. Being:

The molar mass of the compounds are:

So, by stoichiometry they react and are produced:

Then the following rule of three can be applied: if 239 grams of PbS are produced by stoichiometry from 34 grams of H₂S, 18 grams of PbS from how much mass of H₂S is produced?

[tex]mass of H_{2} S=\frac{18 grams of PbS*34 grams of H_{2}S }{239 grams of PbS}[/tex]

mass of H₂S= 2.56 grams

2.56 grams of H₂S is needed to produce 18.00g of PbS if the H2S is reacted with an  excess (unlimited) supply of Pb(CH₃COO)₂

Answer:

Explanation:

Describe means you should recall facts, events or processes accurately. You might need to give an account of what something looked like, or what happened.

Explain means you need to make something clear, or state the reasons for something happening.  

Compare means you need to describe similarities and differences between things. If you are asked to compare X and Y, write down something about X and something about Y, and give a comparison. Do not just write about X only or Y only.

Evaluate means you must use information supplied, or your own knowledge, to consider the evidence for and against or to identify strengths and weaknesses. You must then complete your answer with a conclusion, stating which is better and why, for example.

Answer:

Although chlorine itself usually does not cause environmental harm, it combines rapidly to form chemicals such as dioxins that pollute water, contaminate fish and transfer to humans and larger animals that eat the fish.

Explanation:

Answer:

Mass of Ag produced = 64.6 g

Note: the question is, how many grams of Ag is produced from 19.0 g of Cu and 125 g of AgNO3

Explanation:

Equation of the reaction:

Cu + 2AgNO3 ---> 2Ag + Cu(NO3)2

From the equation above, 1 mole of Cu reacts with 2 moles of AgNO3 to produce 2 moles of Ag and 1 mole of Cu(NO3)2.

Molar mass of the reactants and products are; Cu = 63.5 g/mol, Ag = 108 g/mol, AgNO3 = 170 g/mol, Cu(NO3)2 = 187.5 g/mol

To determine, the limiting reactant;

63.5 g of Cu reacts with 170 * 2 g of AgNO3,

19 g of Cu will react with (340 * 19)/63.5 g of AgNO3 =101.7 g of AgNO3.

Since there are 125 g of AgNO3 available for reaction, it is in excess and Cu is the limiting reactant.

63.5 g of Cu reacts to produce 108 * 2 g of Ag,

19 g of Cu will react to produce (216 * 19)/63.5 g of Ag = 64.6 g of Ag.

Therefore mass of Ag produced = 64.6g

Answer:

The smallest constituent of an element is termed as an atom. According to Jaiden, an atom comprises two subatomic particles and three prime parts, however, this is incorrect as an atom comprises three subatomic particles and two main parts. The three subatomic particles are the protons, electrons, and neutrons. All these parts are smaller in comparison to an atom, thus, they are considered as subatomic particles.  

To be considered as an atom, an atom is needed only electrons and neutrons, like hydrogen exhibit one electron and one proton. On the other hand, the overall charge of the atom is not affected by the presence of neutrons, it is the subatomic particle that only enhances the mass of the atom.  

Answer:

I disagree with her because an atom has two main parts: the nucleus and the electron cloud. Atoms have three subatomic particles: protons, neutrons, and electrons.

Explanation:

Answer:

Molar mass Na2CO3 = 2*23 + 12 + 3*16 = 106 g/ mol

Mass of 1 mol Na2CO3 = 106 g

mass (Na2CO3) = 106g*250cm³/1000cm³ = 26.5 g

1) It is necessary because all Na2CO3 will be in the solution, and no Na2CO3 would be lost.

2) Because the solution that was formed after rinsing beaker contains Na2CO3.

3) Eyes should be on the level of calibration mark of the volumetric flask.

4) It is necessary to prevent evaporation of water, and changing , because of it, the concentration of the solution.

Answer:

Urea contains more nitrogen

Explanation:

1 mole of Urea contains 2 moles of Nitrogen and 1 mole of ammonium sulfate contains, also, 2 moles of nitrogen.

60g of urea (Molar mass: 60g/mol) contains:

60g × (1mol / 60g) = 1 mole. As 1 mole of urea contains 2 moles of nitrogen, moles of nitrogen are 2.

100g of ammonium sulfate (Molar mass: 132g/mol) contains:

100g × (1mol / 132g) = 0.758 moles.

As 1 mole of urea contains 2 moles of nitrogen, moles of nitrogen are 0.758×2 = 1.516 moles.

That means, urea contains more nitrogen.

Answer:

It is a metaphorical line that divides the earth from north to south

Explanation: