When iron combines with oxygen in a moist environment, rust forms because of a
A.
change in density.
B.
chemical reaction.
C.
change in temperature.
D.
physical reaction.

Students performed an investigation on how aluminum cans taken to a recycle center were able to be reused. They found out an aluminum can undergoes which type of change?
A.
a physical change because the material remains the same
B.
a chemical change because new metal is formed
C.
a physical change because the can is heated
D.
a chemical change because an old can is changed into a new can

Which of the following is an example of a compound?
A.
carbon
B.
copper
C.
water
D.
iron

A student placed a small chip of limestone into a hydrochloric acid solution, and carbon dioxide gas was released. The carbon dioxide provided evidence that
A.
only a loss of mass occurred.
B.
only a physical change occurred.
C.
the formation of an element occurred.
D.
a chemical change occurred.

As part of a study, a scientist observed a number of different molecular changes in matter. Which of the following observations provides evidence of a physical change?
A.
a cake that was baked from many ingredients
B.
using heat to burn a log in a fireplace
C.
using light to produce sugar in plants
D.
a bottle that was broken into many small pieces

What is formed when a sodium atom and chlorine atom react chemically?
A.
an electron
B.
a neutron
C.
a compound
D.
an element

Which substance is composed of only one type of atom?
A.
salt
B.
water
C.
gold
D.
sugar

A mixture that has the same composition throughout is what kind of mixture?
A.
Taco Salad
B.
Heterogeneous
C.
Sharknado
D.
Homogeneous

John and Lisa collected a sample of ocean water and placed it in a jar. Within a couple of days, the water had evaporated and salt was visible at the bottom of the jar. This is an example of a
A.
solute being dissolved.
B.
chemical change.
C.
new substance being formed.
D.
physical change.

Which term correctly describes all of the following materials?

salt water, vinegar, bronze, air, beach sand



A.
solutions
B.
mixtures
C.
compounds
D.
elements

In which classification of matter are the components chemically combined?
A.
alloy
B.
compound
C.
mixture
D.
colloid

Since sodium chloride is classified as a compound, a sample of it contains
A.
matter that cannot be reduced to atoms.
B.
atoms that are gases, liquids, and solids.
C.
a solution of atoms and molecules.
D.
more than one kind of atom.

Which is the best example of a chemical change?

A.
paper tearing

B.
butter melting
C.
egg cooking

D.
water evaporating

Which is a physical change?
A.
rust forming on an iron fence
B.
a copper roof changing color
C.
a sheet of paper shredding
D.
a piece of wood burning

What is needed to change ice into water?
A.
stirring
B.
energy
C.
chemicals
D.
air

A group of students observed the formation of bubbles when water boiled. What happened to matter because of the physical change to the water?
A.
Matter was conserved when it changed form.
B.
New matter was created in the bubbles.
C.
Old matter was destroyed as the water turned to gas.
D.
The composition of the matter changed.

Which of the following results when hydrogen and chlorine chemically bond to form hydrogen chloride?
A.
a compound
B.
a solution
C.
a precipitate
D.
a mixture

What is the smallest unit of an element that still retains the element’s properties?
A.
an atom
B.
a crystal
C.
a molecule
D.
a proton

Which type of matter can be separated by physical means?
A.
compound
B.
element
C.
mixture
D.
atom

Which state has a definite shape and volume?

A.
Sharknado 2: The Second One
B.
Gas
C.
Solid
D.
Liquid

Answer:

The cation is written first in the name; the anion is written second in the name. Rule 2. When the formula unit contains two or more of the same polyatomic ion, that ion is written in parentheses with the subscript written outside the parentheses.

When writing the formula of a compound that contains polyatomic ion, the metal is written first followed by the central atom in the ion and then other atoms that surround the central atom.

A poly atomic ion refers to an ion that comprises of more than one atom. Such ions are common in chemistry. Examples of polyatomic ions include; PO4^3-, BH4^- etc.

When writing the formula of a compound that contains a polyatomic ion, the metal is written first then the central atom in the ion follows before other atoms that surround the central atom in the ion.

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Answer:

HX (aq)    +     H₂O (l)  ⇄      H₃O⁺ (aq)    +     X⁻ (aq)  

Acid                  Base          Conj. acid          Conj. base  

Explanation:

The equation is:

HX (aq) + H₂O (l)  ⇄   H₃O⁺ (aq) + X⁻ (aq)

This is the typical equilibrium for a weak acid. It would complete if we notice the Ka.

HX (aq) + H₂O (l)  ⇄   H₃O⁺ (aq) + X⁻ (aq)    Ka

1 mol of hypothetic HX acid react to 1 mol of water in order to release a proton and make hydronium and generate the X⁻ anion.

HX will be the acid, in this case a weak one and water will be the base. Water is able to accept a proton to make itslef hydronium

Hydronium is the conjugate acid.

The X⁻ will be the conjugate strong base.

This ion can generate the acid form again, that's why it is strong, because it can make hydrolisis.

X⁻ (aq)  +  H₂O (l)  ⇄  HX (aq) +  OH⁻(aq)     Kb

In this case, the anion will be the conjugate base which it takes a proton from water (acid form) to make a conjugate acid, the HX and a conjugate base, OH⁻

Answer:

ertyuioekgdctifrofy?

Explanation:

Answer:

oxygen ion O2-

Explanation:

because it has 8 protons and gave gained 2 electron so O2-.

Answer:

1.95 M

Explanation:

Molarity is a measure of the molar concentration of a substance (solution). In relation to the volume, it is calculated using the formula as follows;

C1V1 = C2V2

Where;

C1 = initial concentration (M)

C2 = final concentration (M)

V1 = initial volume (L)

V2 = final volume (L)

According to the provided information in this question;

C1 = 14.38 M

C2 = ?

V1 = 1.28 L

V2 = 9.45 L

Using C1V1 = C2V2

14.38 × 1.28 = C2 × 9.45

18.4064 = 9.45 C2

C2 = 18.4064 ÷ 9.45

C2= 1.95 M

Answer:

Explanation:

I can’t explain but this is the answer LOL

Answer:

Do you need your 0.00 2 oz

Explanation:

Because that is the right answer

For the enough dissolving of given moles each group will need to provide 92mL of solution.

Molarity can be calculated as: M = n/V mol/L where,

V = volume = 3L (given)

n = no. of moles, which can be calculated as:

n = W/M, where

W = given mass = 42.1g (given)

M = molar mass = 56.1g/mol (known)

First of all we have to calculate molarity to determine the volume of solution of each groups. By putting value of n in the 1st equation, molarity can be calculated as follow:

M = 42.1 / 56.1 × 3 = 0.250 mol/L

Now in the question it is given that each group have KOH solution of 0.023 moles. So, we can calculate the volume by using the 1st equation:

M = n/V

0.250 = 0.023/V

V = 0.023mol / 0.250mol per L = 0.092L = 92mL.

Hence, 92mL of the solution will each group need to provide enough dissolved moles

To learn more about molarity, visit the below link:

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Reaction takes place is

2KClO3 --> 2KCl + 3O2

from above equation 2 moles of potassium chlorate is forming 3 moles of Oxygen gas.

now given 6.83 moles of oxygen and moles of potassium chlorate is missing,

consider x moles of potassium chlorate are needed to form 6.83 moles of oxygen

from above condition, .

3 》》》》2

x 》》》》6.83

3/x = 2/6.83

x = 3×6.83/2

x= 10.245

Answer- 10.245 moles of potassium chlorate are needed to produce 6.83 moles of oxygen gas.

Answer:

4

3

2

6

1

5

I hope this helped!

Answer:

The atmosphere can be divided into layers based on its temperature, as shown in the figure below. These layers are the troposphere, the stratosphere, the mesosphere and the thermosphere.

Answer:

Its a simple SERIES circuit

Explanation:

Answer: number of atoms is 5.21 · 10^24

Explanation: Atomic mass of Be is 9.012 g/mol.

Number of moles n = m/M = 78.0 g / 9.012 g/mol =

Multiply this with Avogadro number Na = 6.022*10^23 1/mol

Answer:

when the velocity is at a higher *rate of speed*, the faster the object will move!

Explanation:

Answer: 10. The reactant in Reaction B is [tex]H_{2}O_{2}[/tex].

11. The products in Reaction B are [tex]H_{2}O[/tex] and [tex]O_{2}[/tex].

12. There are 2 molecules present on the reactant side of the equation.

13. There are 3 molecules present on the product side of the equation.

Explanation:

The given reaction equation is as follows.

[tex]Reaction B: 2H_{2}O_{2}(aq) \rightarrow 2H_{2}O(l) + O_{2}(g)[/tex]

Reactants are the species present on the left side of a chemical equation.

Products are the species present on the right side of a chemical equation.

Therefore, the reactant in Reaction B is [tex]H_{2}O_{2}[/tex]. As 2 is coefficient of [tex]H_{2}O_{2}[/tex] so, 2 molecules are present on the reactant side of the equation.

The the products in Reaction B are [tex]H_{2}O[/tex] and [tex]O_{2}[/tex]. The coefficient of [tex]H_{2}O[/tex] is 2 and coefficient of [tex]O_{2}[/tex] is 1. Hence, there are total (2 + 1) equals to 3 molecules present on the product side of the equation.

Thus, we can conclude that:

The reactant in Reaction B is [tex]H_{2}O_{2}[/tex].

The products in Reaction B are [tex]H_{2}O[/tex] and [tex]O_{2}[/tex].

There are 2 molecules present on the reactant side of the equation.

There are 3 molecules present on the product side of the equation.

Answer:

See explanation.

Explanation:

Hello there!

In this case, according to the described chemical reaction, we first write the corresponding equation to obtain:

[tex]Cu+2AgNO_3\rightarrow 2Ag+Cu(NO_3)_2[/tex]

Thus, we proceed as follows:

Part 1 of 3: here, since the molar mass of silver and copper (II) nitrate are 107.87 and 187.55 g/mol respectively, and the mole ratio of the former to the latter is 2:1, we can set up the following stoichiometric expression:

[tex]m_{Cu(NO_3)_2}=1.29gAg*\frac{1molAg}{107.87gAg}*\frac{1molCu(NO_3)_2}{2molAg}*\frac{187.55gCu(NO_3)_2}{1molCu(NO_3)_2} \\\\m_{Cu(NO_3)_2}=1.12gCu(NO_3)_2[/tex]

Part 2 of 3: here, the molar mass of copper is 63.55 g/mol and the mole ratio of silver to copper is 2:1, the mass of the former that was used to start the reaction was:

[tex]m_{Cu}=1.29gAg*\frac{1molAg}{107.87gAg}*\frac{1molCu}{2molAg}*\frac{63.55gCu)_2}{1molCu} \\\\m_{Cu}=0.380gCu[/tex]

Part 3 of 3: here, the molar mass of silver nitrate is 169.87 g/mol and their mole ratio 2:2, thus, the mass of initial silver nitrate is:

[tex]m_{AgNO_3}=1.29gAg*\frac{1molAg}{107.87gAg}*\frac{2molAgNO_3}{2molAg}*\frac{169.87gAgNO_3}{1molAgNO_3} \\\\m_{AgNO_3}=2.03gAgNO_3[/tex]

Best regards!

Answer:

1.)C₃H₈O

2)OH

3.)1-propanol

1.) C4H8O

2.) C2H6O or CH3CH2OH

3.)Ethanol

Explanation:

Hope this help

Answer:

Iron is limiting reactant

Explanation:

Based on the reaction:

Fe + S → FeS

1 mole of iron reacts per mole of Sulfur

To solve this question we must convert the mass of each reactant to moles using molar masses of each reactant. As the reaction is 1:1, the reactant with the lower amount of moles is limiting reactant.

Moles Fe -Molar mass: 55.845g/mol-

4.68g * (1mol / 55.845g) = 0.0838 moles

Moles S -Molar mass: 32.065g/mol-

2.88g * (1mol / 32.065g) = 0.0898 moles

As the amount of moles of Fe < Moles S,

Iron is limiting reactant

When 4.68 g of iron reacts with 2.88 g of sulfur to produce FeS, iron is the limiting reagent.

If in a chemical reaction two reactants are present and one of them is present in less quantity as compared to other, is known as limiting reagent.

Given chemical reaction is:
Fe + S → FeS

From the stoichiometry of the reaction it is clear that equal moles of both reactant is required for the formation of product, so their mole ratio is 1:1.

Now we calculate the moles by using the formula:

n = W/M, where

W = given mass

M = molar mass

Moles of 4.68g of iron = 4.68g / 55.845g/mole = 0.0838 moles

Moles of 2.88 of sulfur = 2.88g / 32.065g/mole = 0.0898 moles

Moles of iron is less as compare to the sulfur, so it is the limiting reagent.

Hence, iron is the limiting reagent.

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Answer:

Oil spills into rivers, bays, and the ocean most often are caused by accidents involving tankers, barges, pipelines, refineries, drilling rigs, and storage facilities.

Spills can be caused by:

people making mistakes or being careless.

equipment breaking down.

natural disasters such as hurricanes.

deliberate acts by terrorists, countries at war, vandals, or illegal dumpers.

Explanation:

Hope this helped Mark BRAINLIEST!!!

Answer:

There will be 4 moles of NO2 produces at the end of the reaction.

Explanation:

First of all, you should consider that the limiting reactant is NO, since it's the first it's going to end in the reaction.

After that, the conversion factor must be done with the limiting reactant (NO). So since you have 4 mol of NO and the relation of NO with NO2 its 2:2, you will end up having 4 moles of NO2.

Answer:

functional

Explanation:

c is correct

Answer: The statement they have one electron in the outermost electron shell. These are very active metals and easily lose their single valence electron, is true.

Explanation:

Metals are the species which tend to lose electron(s) to acquire stable noble gas configuration.

Elements which tend to lose a single electron in order to acquire stability are active in nature because losing one electron is more easy as compared to losing two or more electrons.

For example, atomic number of sodium is 11 and its electronic distribution is 2, 8, 1.

Since, it contains only one valence electron and by losing it sodium will acquire stability. Hence, sodium is a very reactive metal.

Thus, we can conclude that the statement they have one electron in the outermost electron shell. These are very active metals and easily lose their single valence electron, is true.

Answer:

[tex]\boxed {\boxed {\sf 16.68 \ g\ Ca(OH)_2}}[/tex]

Explanation:

Molarity is a measure of concentration in moles per liter.

[tex]molarity = \frac{moles \ of \ solute}{liters \ of \ solution}[/tex]

The molarity is 0.450 moles per liter. The moles of solute is unknown.

The volume of the solution is 500 milliliters, but we want to know the liters. We need to convert the units. Remember that 1 liter contains 1000 milliliters.

So, we have values for all the variables:

Substitute the values into the formula.

[tex]0.450 \ mol /L *\frac{x}{0.500 \ L}[/tex]

We want to solve for x, the moles of solute. x is being divided by 0.500 liters. The inverse of division is multiplication, so multiply both sides by 0.500 L.

[tex]0.500 \ L *0.450 \ mol /L =\frac{x}{0.500 \ L}*0.500 \ L[/tex]

[tex]0.500 \ L *0.450 \ mol /L =x[/tex]

The units of liters cancel.

[tex]0.500 *0.450 \ mol=x[/tex]

[tex]0.225 \ mol =x[/tex]

Now we have the moles and need to convert to grams. This is done using the molar mass (mass per 1 mole). The values are found on the Periodic Table as atomic masses, but the units are grams per mole instead of atomic mass units.

The solute is Ca(OH)₂, so lookup the molar masses of the individual elements.

Note there is a subscript of around OH. There are 2 hydroxide molecules, so there are 2 oxygen and 2 hydrogen atoms. We must multiply their molar masses by 2 before adding all the values.

Use the molar mass as a ratio.

[tex]\frac{74.094 \ g \ Ca(OH)_2} {1 \ mol \ Ca(OH)_2}[/tex]

Multiply by the number of moles calculated.

[tex]0.225 \ mol \ Ca(OH)_2 *\frac{74.094 \ g \ Ca(OH)_2} {1 \ mol \ Ca(OH)_2}[/tex]

The units of moles of calcium hydroxide cancel.

[tex]0.225 *\frac{74.094 \ g \ Ca(OH)_2} {1}[/tex]

[tex]16.67115 \ g\ Ca(OH)_2[/tex]

16.68 grams of calcium hydroxide are needed.

Answer:

[tex]\frac{131}{53} I[/tex]

Explanation:

A naturally occurring element is an element that is not produced in a nuclear reaction.

Most of the trans-uranium elements are not natural, they are all synthetic elements which are produced as a result of nuclear reactions. They are unknown in nature.

Apart from [tex]\frac{131}{53} I[/tex], all other radioisotopes listed among the options are not natural elements.They are products of nuclear reactions.

When the average kinetic energy of its particles increases, the object's thermal energy increases. Therefore, the thermal energy of an object increases as its temperature increases.

In chemistry, we define the temperature of a substance as the average kinetic energy of all the atoms or molecules of that substance. Not all of the particles of a substance have the same kinetic energy. At any given time, the kinetic energy of the particles can be represented by a distribution.

In physics, temperature is defined as the average kinetic energy of the particles in an object. ... When particles move more quickly, temperature is higher and an object feels warmer. When particles move more slowly, temperature is lower and an object feels cooler.

乁(ᵔヮᵔ)ㄏ

Answer:

P₂ = 300 atm

Explanation:

Given that,

Initial volume, V₁ = 600 L

Initial pressure, P₁ = 400 atm

We need to find the pressure if the volume is 800 L.

We know that the relation between pressure and volume is given by :

[tex]P\propto \dfrac{1}{V}\\\\\dfrac{P_1}{P_2}=\dfrac{V_2}{V_1}\\\\P_2=\dfrac{P_1V_1}{V_2}\\\\P_2=\dfrac{600\times 400}{800}\\\\P_2=300\ atm[/tex]

So, the new pressure is equal to 300 atm.

Answer:

D. I am pretty sure

Explanation:

:))))))

Answer:

D. A teacher lights a candle

Explanation:

Answer:

D) An acid group present in lipids