PLZZZZ HELP!!!!!! WILL GIVE BRAINLIEST!!
Select all the signs of a CHEMICAL change from the list below. (You may need to select more than one for full points)

Evaporating

Bubbles (gas formation)

color change

dissolving

physical properties for a bar of soap: hardness and color

physical properties for a book: texture and size

physical properties for tooth past: cohesiveness and taste

Answer: The correct answer is:

1. Metal pot: Hardness, fusibility

2. Glass cup: Transparent, resistant

3. Sheet of paper: White, porous

Explanation:

A physical property is one that is based primarily on the structure of the object, substance or matter, which is visible and measurable.

We can define the physical properties of an object through observation and measurement. For example, the physical properties of a wooden cube would be: dense, solid, square, wooden, organic, non-malleable, etc.

Page 1  

1: The grass

2: The grasshopper

3: The frog

4: The snake

5: The eagle

Page: 2

The answer is the 2nd one

Page: 3

The owl would because its at the end it would have almost no more sun energy left in whatever it eats.

Hope This Helps :)

Grass, Grass Hopper, Frog, Snake, then Hawk.

For the food web question, it would be the third option because most organisms eat more than one thing.

The original source of energy in most ecosystems is the sun.

The owl would receive the least amount of energy because each level of the food chain only gains 10% of the organisms energy.

Atoms of Cr in 0.86 mol of K2CrO4 = 0.86 × 6.02*10^23 = 5.177 * 10^23 atoms.

To find the number of atoms of chromium in 0.86 mol of potassium chromate, you multiply the moles by Avogadro's number, resulting in approximately 5.18 x 10²³ Cr atoms.

To calculate how many atoms of chromium are in 0.86 mol of potassium chromate (K₂CrO₄), we have to understand the composition of the compound potassium chromate. Potassium chromate consists of two potassium (K) ions, one chromium (Cr) atom, and four oxygen (O) atoms. Since there is one Cr atom in each formula unit of K₂CrO₄, the number of Cr atoms will be equal to the number of moles of K₂CrO₄ given.

To find the number of Cr atoms, we use Avogadro's number, which states there are approximately 6.022 x 10²³atoms in one mole of any substance. Therefore, we calculate the number of atoms of chromium by multiplying the number of moles of K₂CrO₄ by Avogadro's number:

Number of molecules = Number of moles × Avogadro’s number

Number of molecules = 0.86moles×(6.022 × 10²³ molecules/mol)

Number of molecules ≈ 5.18 × 10²³ molecules

Answer: 1,360.776 grams

Explanation: given that a recipe/batch

requires 1 pound of butter

3 pounds would require x

Crosss multiplying we have

X=3 pounds

Converting pound to grams

1 pound =453.592grams

3pound =x grams

Xgrams =453.592*3

X=1,360.776 grams

Hey there!

The pH of a weak base (in this case, pyridine is a weak base) is calculated by using the weak base equation, and then solving it.

C5H5N; Kb= 1.7 x 10⁻⁹

pH = -log [H⁺]

we can also say that pH = 14 + log [OH⁻]

Plugging into the weak base equation, we know that Kb = [OH⁻][BH⁺] / [B]

This can be solved using an ice chart, which will then simplify to :

Kb = [x][x] / [0.50-x]

We can assume that x is very small in comparison to the 0.5 , so we consider it zero.

Then plug in and solve for x.  1.79 *10-9 = x² / 0.5

x = 2.992 * 10⁻⁵

ince X is equal to the [OH⁻] concentration, we can plug it into the second pH equation, and get the pH!

pH = 14+ log 2.99 * 10⁻⁵

pH = 9.48

Hope that helps!

The pH of a 0.65 M solution of pyridine (C₅H₅N) is 9.52.  

The equation for the protonation of the base pyridine is the following:

C₅H₅N + H₂O ⇄ C₅H₅NH⁺ + OH⁻   (1)

The constant of the above reaction is:

[tex] K_{b} = \frac{[C_{5}H_{5}NH^{+}][OH^{-}]}{[C_{5}H_{5}N]} = 1.7 \cdot 10^{-9} [/tex]    (2)

To calculate the pH of the solution we need to use the following equation:

[tex] pH + pOH = 14 [/tex]      

[tex] pH = 14 - pOH = 14 - (-log[OH^{-}]) = 14 + log[OH^{-}] [/tex]   (3)

So, we need to find the concentration of the OH⁻ ions. Since pyridine is a weak base, at the equilibrium we have (eq 1):

C₅H₅N  +  H₂O  ⇄  C₅H₅NH⁺  +  OH⁻

0.65 - x                          x              x

After entering the values of [C₅H₅N] = 0.65-x, [C₅H₅NH⁺] = x, and [OH⁻] = x, into equation (2) we can find the concentration of OH⁻:

[tex] 1.7 \cdot 10^{-9} = \frac{[C_{5}H_{5}NH^{+}][OH^{-}]}{[C_{5}H_{5}N]} = \frac{x*x}{0.65 - x} [/tex]  

[tex] 1.7 \cdot 10^{-9}(0.65 - x) - x^{2} = 0 [/tex]  

Solving the above quadratic equation for x, we have:

[tex] x_{1} = -3.32 \cdot 10^{-5} M [/tex]

[tex] x_{2} = 3.32 \cdot 10^{-5} M [/tex]        

We can calculate the pH, after taking the positive value, x₂, (concentrations cannot be negative) and entering into equation (3):

[tex] pH = 14 + log[OH^{-}] = 14 + log(3.32 \cdot 10^{-5}) = 9.52 [/tex]  

Therefore, the pH of the solution of pyridine is 9.52.

Find more about pH here:

I hope it helps you!    

When describing the velocity of an object, you must specify the both the speed and the direction.

That’s because velocity is a vector: it has both magnitude (speed) and direction.

If you say that a object is travelling southwest at 70 km/s, you are giving its velocity.

If you say that it is travelling at 70 km/s, you are giving its speed.

Final answer:

To describe the velocity of an object, you must specify the magnitude of speed and its direction, reflecting that velocity is a vector quantity unlike speed, which is scalar.

Explanation:

To describe the velocity of an object, one must specify two key things: (1) the magnitude of the speed, which is a scalar quantity representing how fast the object is moving, and (2) the direction of travel, which informs us of the orientation of the object's motion in space. For example, an object moving at 20 meters per second towards the north has a velocity that can be expressed as '20 m/s north'. This descriptive pairing of speed and direction is what differentiates velocity from speed, making velocity a vector quantity.

When illustrating velocity, a vector representation is often used, which is not always to scale but indicates direction and relative magnitude. For instance, in the case of the two airplanes with different speeds and directions discussed in the question, their velocities can be represented by arrows with lengths proportional to their speeds and pointing in the respective directions of travel - northeast and southwest.

The seaweed would be the producer in this exact food web.

Since the seaweed is the main source of food in that food web, it supplies everything else in the food web by supplying the animal that eats it, which supplies the animal that eats that animal, and so on.

Confusing, right?

Have a great day :)

Answer: seaweed

Explanation:

it’s the only plant in this food web

Answer:

c fluorine

Explanation:

Trace fossils provide us with indirect evidence of life in the past, such as the footprints, tracks, burrows, borings, and feces left behind by animals, rather than the preserved remains of the body of the actual animal itself. so i would say B.

The option that can be classified as a trace fossil is b.shrimp burrow

A trace fossil is a fossil that contains traces of ancient plants or animals such as footprints, nests, burrows, or excrement in an indirect, visible manner. Ichnology is the field of study of trace fossils.

Body fossils and trace fossils are frequently discovered together in the same area. Instead of the preserved remnants of the actual animal's body, trace fossils offer us indirect proof of life in the past in the form of animal footprints, tracks, burrows, borings, and feces.

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Answer:

The correct answer is forms droplets

In a covalent bond, two atoms are held together by the attraction between each atom and the shared electrons. the number of covalent bonds that an atom can form depends on the number of valence electrons in the atom.

hope dis helped u daddy

Answer: each atom and the shared electrons,

valence electrons

Explanation: A covalent compound is defined as the compound which is formed from the sharing of electrons between the element that are combining together.

These compounds are most likely to be formed when two non-metals combine together. For Examples: [tex]F_2[/tex]

Flourine is an element with tomic number 9 and has 7 valence electrons

[tex]F:9:1s^22s^22p^5[/tex]

Thus for formation of  a [tex]F_2[/tex] molecule, they share their valence electrons and attain stable configuration.

Ok. Sodium is used in the everyday things we eat or known as naCI. It is also used a reactor for nuclear things. It is also added to snow to de-ice the roads in winter.

Answer:

Conceptual model - a diagram that shows the shape of the magnetic field around an object

Physical model - several balls and sticks glued together to represent a molecule

Virtual model - a computer program that shows all possible planetary orbits

Mathematical model - an equation that shows how an object’s acceleration relates to its mass

Explanation:

happy to help :^)

The correct pairings of conceptual models with their corresponding examples:

A physical model is a copy or imitation of something that helps us see and understand its features, how it behaves, or its design. Physical models are objects that you can touch and are in three dimensions. They can be similar to a smaller version of a building or simple objects like balls and sticks that represent molecules.

A virtual or computer-made picture  of something that you can use to study and interact with. Virtual models are frequently used in simulations and computer programs to imitate real-life events or situations. An example is a computer program that displays how planets move in their paths around the sun.

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Is Does not have a Coefficient so it would be No

Answer:- D.  [tex]Li_2CO_3(aq)+FeCl_2(aq)\rightarrow 2LiCl(aq)+FeCO_3(s)[/tex]

Explanations:- In chemical equations, (aq) stands for aqueous, (l) stands for liquid, (g) stands for gas and (s) stands for solid. In double replacement reactions, (aq) means soluble and (s) means insoluble that is precipitate.

Looking at all the equations, it is only the last equation that has a solid product and so this is the only precipitation reaction. A precipitate for Iron(II)carbonate is formed in it.

Answer:

The correct answer is

D.  Li2CO3(aq) + FeCl2(aq) → 2LiCl(aq) + FeCO3(s)

All of them are very reactive.

Answer : A chemical formula usually represents the chemical species involved in a chemical reaction. It gives a clear information about the chemical proportions of atoms present in an chemical compound.

This chemical formula usually employs the use of chemical element symbols, numbers, etc.

Also, sometimes other symbols are also used like parentheses, dashes, brackets, commas and plus (+) or minus (−) signs.

In the given question [tex]2H_{2}O[/tex] where 2 represents the number of hydrogen atoms present in that chemical species (water molecule), The number of oxygen atom is one because it doesn't  has any number before it.

The subscript [tex]H_{2}[/tex] represents the valency of hydrogen, which is 2 here. In all if we have to calculate the total number of hydrogen in this water molecule which is 4 because 2 X 2=4; this is because 2 hydrogen is multiplied with 2 valency of hydrogen.

The answer is:

Coefficient; how many water molecules there are.

As sunlight heats Venus' surface, the surface radiates infrared energy that is kept from escaping the planet by dense carbon dioxide atmosphere. This is called the greenhouse effect.

The High tempatures on Venus are caused by the Greenhouse effect

A 20 L sample of the gas contains 8.3 mol N₂.

According to Avogadro’s Law, if p and T are constant

V₂/V₁ = n₂/n₁

n₂ = n₁ × V₂/V₁

___________

n₁ = 0.5 mol; V₁ = 1.2 L

n₂ = ?;           V₂ = 20 L

∴n₂ = 0.5 mol × (20 L/1.2 L) = 8.3 mol

i will say ar that all i got

NOBLE GAS IS THE ANSWER

Final answer:

Precision is the term that describes how closely a set of measurements are to each other, indicating the reproducibility of the measures under similar conditions. It differs from accuracy, which measures how close a measurement is to the true value. So the correct option is d.

Explanation:

The measure of how closely a set of measurements are to each other is best defined by the term precision. Precision refers to the reproducibility of measured values when repeated under similar conditions and indicates how close the measurements are to each other. It's important to note that precision is different from accuracy, which is a measure of how close a single measurement is to the correct or true value. Conversely, uncertainty is related to the potential variation in the measurements from the true value, providing an estimate of the range within which the true value lies.

Answer:

if the object is denser then the substance, it will sink, the less dense the object is then it will float

Explanation:

i got it right in my test. :) have a good day

1. I think its B but im not sure imma check again

2. Its D fo sho

One

Let's start by stating what we know is wrong. Equilibrium is achieved when the reactants and products have a stable concentration. That makes D incorrect. Equilibrium is not established until about the 6th or 7th second.

The fact that you get any products at all means that the reactants will become products.  Just who is favored has to be looked at very carefully. The products start very near 0. They go up until their concentration at equilibrium. When the reach equilibrium, the products have increased to 17. The reactants have dropped from 40 to 27. By a narrow margin, I would say the products are favored.

C is incorrect. There are still reactants left.  

E is incorrect. the reactants started out with a concentration of 40. The reaction is not instantaneous.  The concentration was highest at 40 or right at the beginning. This assumes that the reactants were mixed and the products were produced and the water/liquid amount has not changed.

B is incorrect. The concentration of the reactants is higher at equilibrium.

A is wrong. It is product favored.

I'm getting none of the above.

Problem Two

AgBr is insoluble (very). You'd have to work very hard to get them to separate into their elemental form. Just putting AgBr in water isn't enough. Lots of heat and lots of electricity are needed to get the elemental form.

I suppose you should pick B. Mass must be preserved. But if you balanced the equation, it would work with heat and electricity.

C. Sulfur

Is the answer.

your answer is sulfur because the atomic number is the same as protons!

plz mark as brainliest

[tex]\boxed{\text{C. 1-hexene}}[/tex] is an unsaturated hydrocarbon.

Further Explanation:

Hydrocarbons:

The organic compounds consisting of hydrogen and carbon atoms alone are called hydrocarbons. Such compounds can be aromatic, aliphatic, linear, branched or cyclic. Aromatic hydrocarbons, alkanes, cycloalkanes are different types of hydrocarbons.

Types of hydrocarbons:

(I) Saturated hydrocarbons

These are variety of hydrocarbons that contain only single bonds in them and are the simplest hydrocarbons. Saturated hydrocarbons have the general formula of [tex]\text{C}_{\text{n}}\text{H}_{\text{2n+2}}[/tex]  in which n indicates the number of carbon atoms present in it. Examples of saturated hydrocarbons are methane, ethane, butane and propane.

(II) Unsaturated hydrocarbons

The type of hydrocarbons that has multiple bonds in them are known as unsaturated hydrocarbons. Multiple bonds can be either double or triple bonds. Alkenes are those unsaturated hydrocarbons consisting of double bonds in them. For example, ethene, propene, and pentene are alkenes. Alkynes refer to unsaturated hydrocarbons with triple bonds in them. Ethyne and propyne are examples of alkynes. Alkenes are represented by general formula,  [tex]\text{C}_{\text{n}}\text{H}_{\text{2n}}[/tex] while alkynes are represented by general formula of [tex]\text{C}_{\text{n}}\text{H}_{\text{2n-2}}[/tex] .

Alkanes use ‘ane’ as suffix in their naming. Alkenes use ‘ene’ as suffix while ‘yne’ is used in naming of alkynes.

Since 2-methylheptane, 3-ethylpentane and cyclopentane have suffix ‘ane’ in their names and are tered as saturated class of hydrocarbons called alkanes. But 1-hexene has suffix ‘ene’, indicating that it belongs to unsaturated hydrocarbons called alkenes. Therefore 1-hexene is an unsaturated hydrocarbon.

Learn more:

1. What is the empirical formula of the compound? https://brainly.com/question/6126420

2. Write the name of the hydrocarbon: https://brainly.com/question/3551546

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Hydrocarbons

Keywords: hydrocarbons, saturated, unsaturated, alkene, alkyne, CnH2n+2, CnH2n, CnH2n-2, double bonds, triple bonds, single bonds, 1-hexene, cyclopentane, 2-methylheptane, 3-ethylpentane.

The compound which is an unsaturated hydrocarbon is 1-hexene.The correct option is C.

Compound is defined as a chemical substance made up of identical molecules containing atoms from more than one type of chemical element.

Molecule consisting atoms of only one element is not called compound.It is transformed into new substances during chemical reactions. There are four major types of compounds depending on chemical bonding present in them.

Organic compounds have single,double or triple bonds due to which the single organic compounds  are saturated while the other two are unsaturated hydrocarbons with suffix '-ene' or '-yne'.

Thus, the correct option is C.

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1) Balanced chemical reaction:

2HClO₄(aq) + K₂CO₃(aq) → K₂CO₃(aq) + CO₂(g) + H₂O(l).

2) Balanced chemical reaction:

HC₂H₃O₂(aq) + LiHSO₃(aq) → LiC₂H₃O₂(aq) (aq) + SO₂(g) + H₂O(l).

3) Balanced chemical reaction:

(NH₄)₂SO₄(aq) + Ca(OH)₂(aq) → CaSO₄(s) + 2NH₃(g) + 2H₂O(l).

CaSO₄ (calcium sulfate) is insoluble in water.

1) Aqueous perchloric acid reacts with aqueous potassium carbonate to form aqueous potassium perchlorate, carbon dioxide gas and water.

2HClO₄(aq) + K₂CO₃(aq) → 2KClO₄(aq) + CO₂(g) + H₂O(l).

2) Aqueous acetic acid reacts with aqueous lithium bisulfite to form aqueous lithium acetate, sulfur dioxide gas and water.

HC₂H₃O₂(aq) + LiHSO₃(aq) → LiC₂H₃O₂(aq) + SO₂(g) + H₂O(l).

3) Aqueous ammonium sulfate reacts with aqueous calcium hydroxide to form a white precipitate of calcium sulfate, ammonia gas and water.

(NH₄)₂SO₄(aq) + Ca(OH)₂(aq) → CaSO₄(s) + 2NH₃(g) + 2H₂O(l).

Electron cloud model

Answer:

Electron cloud model

Explanation:

on edge