Which sentence is a scientific statement? A. There is a substance around us that cannot be detected. B. Kids should go to school for 12 years. C. Experimentation is the best way to obtain knowledge. D. Unicorns once existed on Earth. E. There are no living things on the Moon

Answer:

10

Explanation:

Answer: 10 neutrons

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

Explanation:

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]

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Answer:

HCO₂H

Explanation:

A buffer is defined as the mixture between a weak acid and its conjugate base, or vice versa, in an aqueous solution.

The HCO₂Na (Sodium formate), is the conjugate base of formic acid, HCO₂H, a weak acid of pKa = 3.75.

Thus, to make a buffer using HCO₂Na, the other substance the buffer should contain is HCO₂H

Answer:

HCO₂H

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:

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:

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

Explanation:

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:

Neutron

Explanation:

Answer: No

Explanation:

A periodic table can be defined as the table in which the row of chemical elements are present. All the elements of the row have same number of electron shells.

The arrangement of elements is based on atomic numbers, electron shell model and other chemical properties. The elements are placed in increasing order of atomic number.

This table does not give information about the occurrence of the elements.

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:

80 MOLES OF WATER ARE PRODUCED WHEN 20 MOLES OF PROPANE ARE BURNED IN EXCESS OXYGEN ON A GAS GRILL.

Explanation:

Equation for the reaction:

C3H8 + 5 O2 --------->  4 H2O + 3 CO2 + Heat

The above equation is in the presence of excess oxygen.

In this reaction,

1 mole of propane forms 4 moles of H2O

If 20 moles of propane were to be used, how many moles of water will be produced?

1 mole of propane = 4 moles of water

20 moles of propane = ( 4 * 20 ) moles of water

= 80 moles of water.

So, if 20 moles of propane were burned in excess oxygen, 80 moles of water will be formed. Propane is heavier than air and when properly combusted produces a large amount of heat. It is also non toxic.

80 MOLES OF WATER are produced when 20.0 moles of propane are burned in excess oxygen on a gas grill.

C₃H₈ + 5 O₂ --------->  4 H₂O + 3 CO₂ + Heat

The above equation is in the presence of excess oxygen.

In this reaction, 1 mole of propane forms 4 moles of H₂O

1 mole of propane = 4 moles of water

20 moles of propane = ( 4 * 20 ) moles of water

20 moles of propane= 80 moles of water.

Thus, if 20 moles of propane were burned in excess oxygen, 80 moles of water will be formed.

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Answer:

e

Explanation:

Answer:

A      20

B      40

C      Ca

D      10

E       9

F      F

Explanation:

The question's incomplete unfortunately, which observations?

Answer:

At very low temperatures, gases expand less for a given pressure change than they do at high temperatures

Answer:

4. Copper(II) carbonate

5. Magnesium carbonate

Explanation:

Only Potassium carbonate, Sodium carbonate and Ammonium carbonate are soluble.

The rest of the carbonates are insoluble.

Answer:

a colloid (heterogeneous mixture) that dispearses the particles intermediate in size.

Explanation:

Answer: The volume is 70872 L

Explanation:

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.

The combined gas equation is,

[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]

where,

[tex]P_1[/tex] = initial pressure of gas (STP) = 1 atm

[tex]P_2[/tex] = final pressure of gas = 99.2 kPa = 0.98 atm  (1kPa=0.0098atm)

[tex]V_1[/tex] = initial volume of gas  = 67000 L

[tex]V_2[/tex] = final volume of gas = ?

[tex]T_1[/tex] = initial temperature of gas (STP)  = 273K

[tex]T_2[/tex] = final temperature of gas = [tex]10.0^0C=(273+10)K=283K[/tex]

Now put all the given values in the above equation, we get:

[tex]\frac{1\times 67000}{273}=\frac{0.98\times V_2}{283}[/tex]

[tex]V_2=70872L[/tex]

Thus the volume is 70872 L

Answer:

2.78

Explanation:

When multiplying, your answer will have the same amount of sig figs as the multicand or multiplier that has the lower number of sig figs. In this case, 4.03 is the one with the lowest number of sigs figs, which is 3 sig figs, so the answer should have 3 sig figs, so the answer is 2.78.

Answer:

B

Explanation:

Oxidation

Zn---> Zn2+ 2e

Reduction

Cu2+ + 2e ---->Cu

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:

Following are the answer to this question:

Explanation:

(1) Calcium oxide (CaO) is also referred to as quicklime. It is the solution for the substance used for whitewashing.  

Whenever it reacts with water ([tex]H_2O[/tex]) and absorbs carbon dioxide ([tex]CO_2[/tex]), it then formed calcium carbonate ([tex]CaCO_3[/tex]), which produced a hard laminate on the walls, to first be whitened by the production of calcium hydroxide (CaOH).  

(2) Slackened lime or calcium hydroxide arises whenever the fast limestone reacts with water.

[tex]CaO(s) + H_2O(l) \rightarrow Ca(OH)_2(aq).[/tex]

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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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:

Copper ii nitrate is the limiting reagent

Explanation:

The first thing to write here is the equation of reaction;

Fe + Cu(NO3)2 ——> Fe(NO3)2 + Cu

When we talk of limiting reagent, we mean the reactant that is totally consumed upon the completion of the chemical reaction

To get the limiting reagent, we can know this by calculating the mass of a specific product formed from each of the masses of the reactants

Now, we can use the amount of copper solid deposited by each of the reactants to know the limiting reagent here.

Since the mole ratio in all cases is 1 to 1, this will be easy

For the iron, the number of moles reacted is mass of iron/ atomic mass of iron

That would be 119.5/56 = 2.134 moles

Now since the mole ratio is 1 to 1, 2.134 moles of copper will be formed

Thus, the mass of copper produced from the iron will be number of moles * atomic mass of copper = 2.134 * 64 = 136.57g

Now from the nitrate, the number of moles is

mass mixed/ molar mass of copper nitrate

molar mass of copper nitrate is 188g/mol

number of moles is thus 279.5/188 = 1.487 moles

Since the mole ratio is 1 to 1, it means that the number of moles of copper produced too is 1.487 moles

The mass of copper produced from this is number of moles of copper * atomic mass of copper

That will be 1.487 * 64 = 95.15g

Now, since the copper nitrate produces less amount of copper solid, it is the the reagent to be consumed first and thus it is our limiting reagent

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:

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:

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:

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

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