160
140
120
100
Temperature (°C)
80
60
40
20
0
0
2 4 6 8
10 12 14 16 18 20 22 24 26
Time (min)
.
At what temp will this substance freeze? 70 CV
At what temp will this substance condense? 70 C
How long will it take to release the heat of vaporization? 3 min
What is the melting point? 70 C
In what physical state did this substance end? Gas
All cooling processes, including phase changes, are Exothermic
At 90 C, what phase of matter is this substance? Liquid

Answer:

Hello your question is incomplete the pH of the solution is unknown hence I will take the pH of the solution be = 4.7

answer : Pka = 5   i.e. > 4.7

Explanation:

Student titrates :

Unknown weak acid ( HA ) with 25 mL of 0.100 M of NaOH ( to a pale pink phenolphthalein endpoint )  then titrates with  11.0 mL of 0.100 M HCL to the solution that contains neutralized unknown acid

Assuming pH of solution = 4.7

HA + NaOH --------> H2O + NaA

at equilibrium  point

0.1 * 25 * 1 = n * 1  ∴   [tex]n_{ha}[/tex] = 2.5 mmoles ------ 1

also

[tex]A^-[/tex]  + HCL ---------> HA + C[tex]L^-[/tex]

at equilibrium point

[tex]n_{a}[/tex] = 1.1 mmoles --------- 2

The ratio of reaction 2 to 1

[tex]\frac{n_{a} }{n_{ha} }[/tex] = 1.1 / 2.5 ≈ 1/2   ( this show that when the pH = 4.7 approximately half of the A^-  have been converted to HA )

Determine the pKa value of the solution

Given that

pH = Pka + log ( A^- / hA )

4.7 = Pka + log ( 1/2 )

therefore Pka = 4.7 - ( -0.3 ) = 5

Answer:

When fossil fuels are no longer available—especially if it happens abruptly, which it potentially will—we're going to see patients dying in hospitals and healthcare facilities due to electricity failure, and this will be particularly acute during natural disasters.”

Answer:

we wouldn't have cars

Explanation:

Answer:

Explanation:

It's 21 /

Answer:

1. 2,1,2

2. 4, 5, 2

3. 1,1,1

4. 1, 1, 1

5. 1, 1, 1

Hope this helps!

Answer: i think is true

Explanation:

True. Cells have jobs in your body as they have functions to do.

Answer:

Option C.

Ilegal dumping of waste

Explanation:

This is because non point source of pollution refers to source of pollution that are many and not directly one which is illegal or does not meet the legal term. This type of pollution does not have a point source, it has many sources and this type of pollution is cause by rainfall or precipitation. Where when the rain fall, it wash away the waste through to water bodies, causing pollution and endangering water bodies.

Answer:

17 kJ/mol

Explanation:

got it on edge

Answer:

honey

Coffee

blood

Explanation:

These components are uniformly distrubuted and these cannot be seperated unlike heterogeneous

The correct formula of the precipitate that is formed is  Na₂SO₄ + Ni(OH)₂.

The solid substance, that is present at the bottom of the liquid, is insoluble in liquid.

The precipitate formed in reacting the nickel sulfate and sodium hydroxide is sodium sulfate and nickel hydroxide.

The formation of precipitate caused by the compound is called precipitant.

Thus, the correct formula for precipitate is Na₂SO₄ + Ni(OH)₂.

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Answer:

b

Explanation:

Answer:

Option D: nitrogen waste

Explanation:

Excretion.

This is removal from of waste products of chemical reactions. It involves the eliminating excess water and salts taken in with our human diet and also spent hormones

Nitrogenous waste products are the human waste products which contain nitrogen and are poisonous to the body.

The kidneys is responsible for the remove of Nitrogenous waste, water, salts, toxins, hormones e. t. c. It is the are the main principle excretory organs. They maintain the constant concentration of materials in the body.

Answer: It wasn't that long ago that frames were made out of cast iron or even wood. Today bicycles are made out of exotic materials such as titanium, aluminum, and carbon fiber. Bicycle frames in the 1990s are lighter and stronger than ever before. A racing bicycle frame with parts of the frameset indicated.

Explanation:

Bicycles are now made of exotic materials like titanium, aluminum, and carbon fiber. Bicycle frames are lighter and stronger than ever before in the 1990s.

Steel is the most common material used in bike frames. Carbon or high-tensile steel is a good, strong, and long-lasting steel, but it isn't as light as its more advanced sibling, chromoly steel.

So we've established that the bike has mass and occupies space, and thus the bicycle is matter.

Some bicycles are constructed from titanium or scandium-aluminum alloyed metals. Some bicycles have a steel alloyed frame.

Thus, Recycling yields aluminum, iron (and steel), magnesium, titanium, zinc, and silica (from glass). Bicycles are now made of exotic materials like titanium, aluminum, and carbon fiber.

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Explanation:

Silver nitrate + iron (III) chloride  --> silver chloride + iron (III) nitrate

The balanced chemical equation is given as;

2FeCl3 + 3Pb(NO3)2 → 2Fe(NO3)3 + 3PbCl2  

Mass of Pb(NO3)2  = 25g

How many grams of iron (III) nitrate were formed?

From the equation;

3 mol of Pb(NO3)2 produces 2 mol of Fe(NO3)3

Converting to mass using;

Mass = Number of moles * Molar mass

Pb(NO3)2;

Mass = 3 mol * 331.2 g/mol

Mass = 993.6 g

Fe(NO3)3;

Mass = 2 mol * 241.86 g/mol

Mass = 483.72 g

This means 993.6 g produces 483.72 g

We have;

993.6 g  = 483.72 g

25 g = x

solving for x;

x = 25 * 483.72  / 993.6

x = 12.1709 g of iron (III) nitrate

Answer:

Wind is Air in a natural motion, as that moving horizontally at any velocity along the earth's surface.

Answer: approximately 15.1 grams.

Explanation: The key to chemistry is to change everything to moles. Then when you have the answer in moles change the answer back to grams, liters, or whatever you want. Change 25 grams of potassium chlorate to moles. Chlorate is Cl with 3 oxygens. ate = saturated. Chlorine has seven valance electrons when it is saturated six of these electrons are used by oxygen ( 2 electrons per oxygen) leaving only 1 electron. 1 K x 39 grams/mole+1 Cl x 35.4grams/ mole+3 O x 16 grams/ mole = 122.4 grams / mole Potassium Chlorate 25 122.4 = moles. 2.05 moles of Potassium Chlorate. There is a 1:1 mole ratio. 1 mole of Potassium Chlorate will produce 1 mole of Potassium Chloride. 2.05 moles of Potassium Chlorate will produce 2.05 moles of Potassium Chloride. Find the gram molecular mass of Potassium Chloride. 1 K x 39 = 39+1 Cl x 35.4 = 35.4 = 74.4 grams / mole. 2.05 moles x 74.4 grams/ mole = 15.2 grams

The mass of O₂ that will be form is 9.8 grams

The chemical reaction is as follows:

2KClO₃ → 2KCl + 3O₂

From the reaction 2 moles of potassium trichlorate decompose to form 2 moles of potassium chloride and 3 moles of oxygen.

Therefore,

molar mass of KClO₃ = 39 + 35.5 + 48 = 122.5 grams

molar mass of O₂ = 32 grams

Therefore,

2(122.5) g of  KClO₃ produces 3(32) grams of O₂

25 g of KClO₃ will produce ? grams of  O₂

cross multiply

mass of O₂  produced = 96 × 25 / 245

mass of O₂  produced = 2400 / 245

mass of O₂  produced = 9.7959

mass of O₂  produced ≈ 9.8 grams

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Answer:

B. This is a decomposition reaction and the mass reading will stay the same as time progresses,

Explanation:

Decomposition reactions are when one reactant decomposes (breaks down) into two or more products. They follow the general form of:

AB --> A + B

The law of conservation of mass tells us that when a chemical reaction takes place, no mass is created or destroyed but transforms from one form to another. You can see from the diagram that you have the same number and type of atoms on each side of the reaction.

Answer:

B

Explanation:

Answer:

Reaction CoCl2 + 2 NaOH -> Co(OH)2 + 2 NaOH

You need to count number of moles of NaOH

Amount of mole is n = m/M = 114 g / 39.998 g/mol = 28,5 mol (about)

Amount of CoCl2 is half from that

Calculate molar mass of CoCl2 and multiply it by 28,5 mol

Explanation:

Answer:

Gold is a metal, more specifically a transition metal, whereas Oxygen is a nonmetal, more specifically a reactive nonmetal. Using this information, you can compare and contrast metals, nonmetals, and metalloids.

Metals are:

Shiny

High melting point

Mostly silver or gray in color

Mostly solids at room temperature – Mercury (Hg) is a liquid at room temperature

Malleable – able to be hammered into a thin sheet

Ductile – able to be drawn/pulled into a wire

Good conductors of heat and electricity

Nonmetals are:

Dull

Low melting point

Brittle – break easily

Not malleable

Not ductile

Poor conductors of heat and electricity

Metalloids are:

Found on the “zig-zag” line on the Periodic Table of Elements

Have properties of both metals and nonmetals

Can be shiny or dull

Semiconductors – able to conduct electricity under certain conditions

Explanation:

Reccomend this site for questions llike these: https://ptable.com/#Properties

Answer:

Find the limiting reagent by calculating and comparing the amount of product each reactant will produce. Balance the chemical equation for the chemical reaction. The reactant that produces a lesser amount of product is the limiting reagent. The reactant that produces a larger amount of product is the excess reagent.

Explanation:

Answer:

c the number of electrons

Answer: I want to say 1

Explanation:

I think

Answer:

no

Explanation:

no

Answer:

0.0721

Explanation:

Answer:

i think it's Organization

Explanation:

The reason being is because they obviously said 'humans' so that's why i think it is Organization

Scientists group similar organisms together through the process called classification. Each similar groups is classified into different organizations.

The arrangement of species into groups according to significant similarities  is known as biological classification. Then, these groups are broken down into more focused, smaller subgroups. Additional details on the species that make up each subgroup are provided.

Organisms are categorized by scientists to make them simpler to research and to facilitate information sharing. Before biologists properly comprehended genetics, the study of biological classification was conducted.

At first, scientists simply categorized creatures based on their outward appearance. Later, as genetic research developed, classification of organisms was based on the genetic and evolutionary links between them.

Therefore, scientists classify each organisms to suitable organizations.

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Answer:

I'd Go. B. weigh everything, let the reaction happen, then weigh everything again.