Identify the number of significant figures in each measurement. Type the correct answer in each box. Use numerals instead of words.

Answer:

a. single replacement reaction

Explanation:

Mg(s) + 2HCl(aq)——-> H2(g) + MgCl2(aq)

Mg replaces H, so this is a single replacement reaction.

Answer:

A. +2

Explanation:

When neutral atom loses electrons, number protons(+)  becomes more than number of electrons(-), so charge of ion is positive.

Answer:

Option A) Exothermic Reaction

Explanation:

In exothermic reaction, the energy is released. The reactants are at high energy while the products are at low energy as shown in the graph.

Answer:

A.) Exothermic reaction

Explanation:

I got it correct on founders edtell

Answer:

500

Explanation:

sddds2

option A is the correct one

It represents Mp orBp of a substance at a specific pressure

Answer:

+ 100 Kj

Explanation:

The very minimum energy required to activate atoms or molecules to undergo chemical transformation.

Answer:

It is 60kj.

Explanation:

It is the highest point minus where a+b is at, so it is 60kj.

Answer:

Metals:

Copper: to make cooking utensils such as pots because it has a high heat conductivity.

Aluminium: to make aluminium foil / soda cans because it is malleable

Mercury: fills up thermometers because it can indicate the temperature when it expands. But it is toxic so fewer people are using mercury thermometers now.

Titanium: to make the body of supersonic aircrafts because it is strong and corrosion resistant

Gold: to make jewelry because it is shiny and also corrosion resistant

Non-metals:

Nitrogen: to fill up chip packages because its molecules are unreactive

Helium: to fill up balloons because it is lightweight

Hydrogen: for generating electricity in hydrogen fuel cells. It is environmentally-friendly because it does not produce any greenhouse gas or toxic pollutants.

Fluorine: added in toothpaste for strengthening the teeth. It can also prevent cavities.

Carbon: the graphite in pencils. this is one form of carbon. Other common forms (allotropes) of carbon include diamond and Buckminsterfullerene (buckyball).

Answer:

The enzyme's active site must be the mold shape of the substrate.

Explanation:

An enzyme and a substrate bind together in order to work. If the shapes of the 2 are different, they will not be able to bond together. If the shapes of the 2 fit glove-in-hand, then they will be able to bond together.

Answer:

Hydrogen is the first element in the periodic table. Oxygen is the eighth element in the periodic table.

Both elements are gases.

Hydrogen is used for the Haber process and rocket fuel.

Oxygen is used for breathing and production purposes.

Air composes 21% oxygen and 0.0001% hydrogen.

Water is an example that contains both hydrogen H2 and oxygen O2 molecules.

Answer:

Hydrogen is the chemical element with the Symbol H and atomic number 1.

Hydrogen is the lightest element in the periodic table and it is the most abundant in the universe.

                                                 WHILE:

Oxygen is the chemical element with the symbol O and the atomic number 8.

It is a member of the chalcogen group in the periodic table.

This is what we humans take in to breathe that gives us life.

Answer:

A. Supersaturated

Explanation:

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The heated solution that holds more dissolved solution than it can hold at a lower temperature is supersaturated solution. Therefore, option A is correct.

A solution that contains more solvent than the typical amount that can dissolve at a specific temperature is said to be supersaturated. By introducing a tiny solute crystal known as a seed crystal, the excess dissolved solvent in a super-saturated solution can begin to recrystallize.

A solution that contains more solvent than the typical amount that can dissolve at a specific temperature is said to be supersaturated. A solution is considered supersaturated if it contains more solute than is necessary to saturate it.

A solution that contains more solute than it can hold at a specific temperature is said to be supersaturated. Usually, raising a solution's temperature causes more particles to dissolve, increasing the solute concentration.

Thus, option A is correct.

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Answer:

Ability to conduct electricity

Melting point

Answer: the acid

Explanation:

Answer:

(c) 82%

Explanation:

Using the chemical reaction:

3CH₃OH + 4MnO₄⁻ → 3HCOOH + 4MnO₂ + 4e⁻

3 moles of methanol produce 3 moles of formic acid (Reaction 1:1)

To find the percent yield we need to calculate theoretical yield of the reaction when 12g of methanol (Molar mass: 32.04g/mol) are reacting, thus:

12g ₓ (1mol / 32.04g) = 0.3745 moles of methanol are in 12g.

As 1 mole of methanol produce 1 mole of formic acid, assuming a 100% of yield in the reaction (Theoretical yield) moles produced of formic acid are 0.3745 moles.

Using molar mass of formic acid (46.03g/mol), mass of the acid in 0.3745moles are:

0.3745 moles ₓ (46.03g/mol) = 17.2g of formic acid are theoretical yield

Percent yield is calculated as:

(actual yield / Theoretical yield) × 100

As actual yield of the reaction is 14g. Theoretical yield is:

(14g / 17.2g) × 100 = 81.2% ≈ 82%

Right answer is:

The percentage yield of the reaction is 82%

The correct answer to the question is Option C. 82%

We'll begin by writing the balanced equation for the reaction.

3CH₃OH + 4MnO₄⁻ → 3HCOOH + 4MnO₂ + 4e⁻

Molar mass of CH₃OH = 12 + (3×1) + 16 + 1 = 32 g/mol

Mass of CH₃OH from the balanced equation = 3 × 32 = 96 g

Molar mass of HCOOH = 1 + 12 + 16 + 16 + 1 = 46 g/mol

Mass of HCOOH from the balanced equation = 3 × 46 = 138 g

From the balanced equation above,

96 g of CH₃OH reacted to produce 138 g of HCOOH

From the balanced equation above,

96 g of CH₃OH reacted to produce 138 g of HCOOH.

Therefore,

12 g of CH₃OH will react to produce = (12 × 138)/96 ≈ 17g of HCOOH.

Actual yield of HCOOH = 14 g

Theoretical yield of HCOOH = 17 g

Percentage yield = Actual / Theoretical × 100

Percentage yield = 14/17 × 100

The correct answer to the question is Option C. 82%

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Answer:

Alkaline earth metals

Explanation:

Group 2 has 2 valence electrons that they lose when being ionized, thus making  their charge 2+.

Answer:

alkali earth metals

Explanation:

ed tell chem

Answer:

One triple bond and four non bonding electrons

Explanation:

In considering the lewis structure of carbon monoxide, we must remember that the molecule contains a total of ten valence electrons. Four are the valence electrons that are present on the valence shell of carbon while six are the valence electrons on oxygen. Some of these valence electrons participate in bonding in the CO molecule.

Out of the six valence electrons on oxygen, two valence electrons participate in bonding with carbon while the other four electrons remain localized on the oxygen atom as two lone pairs of electrons.

Hence there are four nonbonding electrons in the lewis structure of CO as well as one triple bond.

Answer:

Solutes examples are

Air,(gas) humid air (gas), polluted air(gas)

Examples of Solvents are Milk(liquid), water(liquid).,

Pepsi(liquid).

Sea water(liquid)

Explanation:

Solutes are substances that are dissolved and it is present in minute fraction in a solution.

Solvents is the medium that dissolve substances or solutes and it is present in large amount in a solution.

Solutes and solvents for solution.

Solution is formed when substances dissolves in another.

Air: The solvent is nitrogen because it is present in large quantities and the solutes is oxygen because it is present in small quantity.

Pepsi :sugar, caffeine and carbon dioxide as solutes and the solvent is water.

Milk: lactose, some minerals are solutes and Water is the solvent.

Humid air: water is the solutes and gases is the solvent.

Sea water: salt is the solute and water is the solvent.

Polluted air: Air is the solvent and dust particles is the solutes.

Answer:

Explanation:

C + O2 → CO2

Mole of C = 24 g/(12 g/mole)

Mole of C = 2 mole

Mole of molecular O2 = 74 g/(32 g/mole)

Mole of molecular O2 = 2.3125 mole

Since mole of C < mole of O2, then C being the limiting reagent.

From the reaction, it shows that mole ratio between C and O2 = 1 : 1.

So, 2 moles of C will stoichiometrically react with 2 moles of O2 to generate 2 moles of CO2.

Avogadro's law states that :"equal volumes of all gases, at the same temperature and pressure, have the same number of molecules i.e. 6.02 x 10^23 molecules/mole.

Therefore, 2 moles of CO2 contain 2 moles x 6.02 x 10^23 molecules/mole = 1.204 x 10^24 molecules of CO2 is formed.

Answer:

See in the pic

Explanation:

Answer:

Explanation:

4). Ca(NO₃)₂ + Na₂SO₄ → CaSO₄ + 2Na(NO₃)₂

  This question is incorrect.

  Since, the final product by reacting Na⁺⁺ and NO₃⁻⁻ is NaNO₃

  Correct equation will be,

  Ca(NO₃)₂ + Na₂SO₄ → CaSO₄ + 2NaNO₃

  This equation is in the balanced form.

5). Ni(NO₃)₂ + KI → NiI + 2K(NO₃)₂

  Correct equation will be,

  Ni(NO₃)₂ + KI → NiI₂ + 2KNO₃

  [Since final product by reacting Ni⁺⁺ and I⁻ is NiI₂]

  Balanced form of this equation will be,

  Ni(NO₃)₂ + 2KI → NiI₂ + 2KNO₃

6). Ni(NO₃)₂ + KOH → NiOH + K(NO₃)₂

   Correct form of the equation will be

   Ni(NO₃)₂ + KOH → Ni(OH)₂ + KNO₃

   [Since reaction of Ni⁺⁺ and OH⁻ gives Ni(OH)₂ and the reaction of K⁺ and NO₃⁻ gives KNO₃]

   Now balancing this equation,

   Ni(NO₃)₂ + KOH → Ni(OH)₂ + 2KNO₃

                              ↓

  Ni(NO₃)₂ + 2KOH → Ni(OH)₂ + 2KNO₃

Answer:

88 mL of water.

Explanation:

Data obtained from the question include the following:

Volume of alcohol = 12 mL

Percentage of alcohol = 12%

Volume of water =..?

We can thus, obtain the volume of water needed to make 12% of the alcohol solution as follow:

Percentage of the solution = 100%

Percentage of alcohol = 12%

Percentage of water =?

Percentage of water = percentage of solution – percentage of alcohol

Percentage of water = 100 – 12

Percentage of water = 88%

Since 12% of alcohol is equivalent to 12 mL of alcohol, therefore 88% of water will also be equivalent to 88 mL.

Therefore, 88 mL of water is needed to make 12% of alcohol.

Answer:

200 moles of nitric acid are produced from 300.00 mol of nitrogen dioxide.

Explanation:

You know that the balanced reaction is:

3 NO₂ + H₂O ⇒ 2 HNO₃ + NO

The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three. Remember that proportionality is a constant relationship or ratio between different magnitudes.

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:

a ⇒ b

c ⇒ x

So:

[tex]x=\frac{c*b}{a}[/tex]

In this case, the rule of three can be applied in the following way: if 3 moles of NO₂ produce 2 moles of HNO₃ by stoichiometry of the reaction, 300 moles of NO₂ how many moles of HNO₃ do they produce?

[tex]moles of HNO_{3} =\frac{300 moles of NO_{2}*2 moles of HNO_{3}}{3 moles of NO_{2}}[/tex]

moles of HNO₃= 200

200 moles of nitric acid are produced from 300.00 mol of nitrogen dioxide.

Answer:

200.0 mol

Explanation:

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Answer:

glamorize

Explanation:

There are many stories about celebrities being on drugs, and the media seems to deliver the stories in a way that acts as drugs are beneficial and further glamorizes them.

News coverage tends to glamorize drug use.

An examination performed by the national middle on addiction and Substance Abuse at Columbia college discovered that young adults who frequently use popular social media outlets have been more likely to drink, use pills, and buy tobacco than adolescents who both did no longer use social media or used it less regularly.

The effects display that the media impact on the human populace cannot exchange the stabilities of equilibria however can affect the number of drug addicts. Sensitivity analyses are performed to search for powerful control measures for drug treatment.

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Answer:

Reasons water is important

Imagine earth without water. The soil, with no water in it and nothing growing on it, would be lifeless, dead, collapsed into dust, sand, clay or rock.

-Water consumption helps lubricate and cushion your joints, spinal cord, and tissues. This will help you enjoy physical activity and lessen discomfort caused by conditions like arthritis.

-Water is a main component of saliva. Saliva also includes small amounts of electrolytes, mucus, and enzymes. It’s essential for breaking down solid food and keeping your mouth healthy.

Explanation:

Before proceeding to answering the question, we have t understand what we mean by both mixture and compound.

A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids.

A compound on the other hand is a chemical substance composed of many identical molecules composed of atoms from more than one element held together by chemical bonds.

The two other reason why H2SO4 is a compound and not a mixture are;

1)  The components which are Hydrogen, Sulphur and Oxygen cannot be separated by physical means.

2) It has a constant melting and boiling point.

Answer:

Oxidation with FAD is more favorable energetically.

Explanation:

With FAD as the electron acceptor;

∆E'° = (E'° from reduction reaction) – (E'° from oxidation reaction)

∆E'° = (-0.219) - 0.031 = -0.25 V

The standard free energy change, ∆G'° = -nF∆E'° ; where n is number of moles of electrons = 2, F is Faraday's constant = 96.5 KJ/V.mol

∆G'° = -2 × 96.5 KJ/V.mol × (-0.25)

∆G'° = 48.25 KJ/mol

With NAD+ as electron acceptor

∆E'° = (E'° from reduction reaction) – (E'° from oxidation reaction)

∆E'° = (-0.320) - 0.031 = -0.351 V

The standard free energy change, ∆G'° = -nF∆E'° ; n = 2, F = 96.5 KJ/V.mol

∆G'° = -2 × 96.5 KJ/V.mol × (-0.351)

∆G'° = 67.74 KJ/mol

From the above values obtained, the oxidation by FAD is more favorable energetically as the free energy is less positive than with NAD+

to remove iodine sublime

to remove sand filter

to remove water evaporate

Explanation:

1. put the mixture in a beaker

2.Heat the mixture using a watch glass filled with cold water, the iodine will sublime at the base of the watch glass.

3.Add water to sand and salt. Stir for salt to diffuse in the water

4.Filter sand from the solution using a filter paper

5.evaporate the remaining water to remain with Salt crystals.

Answer:

The answer is option B.

3.

Hope this helps you

Answer:

Option C. 8.91g

Explanation:

The balanced equation for the reaction is given below:

2Pb(NO3)2 —> 2PbO + 4NO2 + O2

Next, we shall determine the mass of Pb(NO3)2 that decomposed and the mass PbO produced from the balanced equation.

This is illustrated below below:

Molar mass of Pb(NO3)2 = 207 + 2[14 + (16x3)]

= 207 + 2[14 + 48]

= 207 + 2[62] = 207 + 124

= 331g/mol

Mass of Pb(NO3)2 from the balanced equation = 2 x 331 = 662g

Molar mass of PbO = 207 + 16 = 223g/mol

Mass of PbO from the balanced equation = 2 x 223 = 446g

Summary:

From the balanced equation above,

662g of Pb(NO3)2 decomposed to produce 446g of PbO.

Finally, we can obtain the maximum mass of lead(II) oxide, PbO produced from 13.23g of lead (II) nitrate, Pb(NO3)2 as follow:

From the balanced equation above,

662g of Pb(NO3)2 decomposed to produce 446g of PbO.

Therefore, 13.23g of Pb(NO3)2 will decompose to produce = (13.23 x 446)/662 = 8.91g of PbO.

Therefore, 8.91g of PbO were obtained from the decomposition of 13.23g of Pb(NO3)2

Answer: because ch4 is not considered a acid they said it is too weak

Explanation: