1. Which of these is always evidence of a chemical change?
A. Formation of bubbles
B. Temperature change
C. Change in color
D. Formation of a precipitate

Answers

Answer 1

Answer:

Explanation:

i guess change in colour


Related Questions

2. If you had a glacier and an ice cube, how would the melting points of both differ?

Answers

Answer:

No

Explanation:

Is tardigrade living or non-living? Explain why?

Answers

Answer:

When tardigrades have enough food and water to support their bodily functions, they live out the natural course of their lives, rarely lasting for longer than 2.5 years, according to Animal Diversity Web, a database run by the University of Michigan.

Explanation:

How many grams are in 0.005 moles of lead (IV) sulfate, Pb(SO­4)2 Group of answer choices 1.5 g 502.74 g 0.0045 g 1.996 g

Answers

Answer:

[tex]m_{Pb(SO_4)_2}=1.996 g[/tex]

Explanation:

Hello.

In this case, given the formula of the lead (IV) sulfate, we can compute its molar mass as shown below:

[tex]M_{Pb(SO_4)_2}=m_{Pb}+2*m_S+2*4*m_O\\\\M_{Pb(SO_4)_2}=207.2+2*32+2*4*16\\\\M_{Pb(SO_4)_2}=399.2g/mol[/tex]

Thus, by applying the following mole-mass relationship, we obtain the mass of 0.005 moles of lead (IV) sulfate:

[tex]m_{Pb(SO_4)_2}=0.005mol*\frac{399.2g}{1mol} \\\\m_{Pb(SO_4)_2}=1.996 g[/tex]

Best regards.

Why can certain things only be turned into certain other things? For example, if you mixed flour, sugar, eggs, and other ingredients, you will not make gold. You will not make rubber, or diamond, or straw either. Why not? In the following space, explain why someone cannot make gold by mixing flour, sugar, and eggs.

Answers

Answer:

You cannot make gold with bakery ingredients as gold is made with hydrogen and helium. Not everything follows the same recipe as some objects. There are different recipes for each material which makes sense because minerals aren't made of wheat. Those minerals feel like stone and act like stone, so it wouldn't be logical if it was crafted with flour, sugar and eggs.

Hope this helps.

Gold is a metal of higher value. It cannot be made by simply mixing any substance. Because every substance is made of its own atoms or molecules and it cannot be recreated by other atoms.

What is gold?

Gold is 79th element in periodic table. It is a transition metal placed in d-block elements. Gold is a precious metal have been used in ornaments and  other coatings.

Metals are hard, and they have some peculiar properties such as ductility, malleability. metallic luster etc. Gold is hard, shiny malleable and ductile and thus it can be easily modified into desired shapes and size.

Every substance is made of its own atoms and molecules. Gold is made of its atoms similarly, silver is made of its own atoms. In such a way everything is made by their characteristics atoms which cannot be recreated from other substances. It can only be produced from its minerals and ores.

Hence, gold cannot be produced from materials like rubber, strew ether etc.

To find more about gold, refer the link below:

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Typical frequencies for several types of electromagnetic radiation are given below. Calculate the energy of each type of radiation.

a. A gamma ray: ν = 1.64 ✕ 10^20 s^−1
b. A microwave: ν = 4.95 ✕ 10^10 s^−1
c. An AM radio wave: ν = 2.00 ✕ 10^6 s^−1

Answers

Explanation:

The energy of electromagnetic radiation is given by :

[tex]E=h\nu[/tex]

Where, h is the Planck's constant

(a) A gamma ray, [tex]\nu = 1.64\times 10^{20}\ Hz[/tex]

Energy,

[tex]E=6.63\times 10^{-34}\times 1.64\times 10^{20}\\E=1.08\times 10^{-13}\ J[/tex]

(b) A microwave, [tex]\nu = 4.95\times 10^{10}\ Hz[/tex]

Energy,

[tex]E=6.63\times 10^{-34}\times 4.95\times 10^{10}\\E=3.28\times 10^{-23}\ J[/tex]

(c) A AM radio wave, [tex]\nu = 2\times 10^{6}\ Hz[/tex]

Energy,

[tex]E=6.63\times 10^{-34}\times 2\times 10^{6}\\E=1.32\times 10^{-27}\ J[/tex]

Therefore, this is the required solution.

Luster, conductivity, and malleability are physical properties of metals. What makes these properties different from chemical properties?

A. Physical properties relate to elements rather than compounds.

B. Physical properties appear only after a chemical change occurs.

C. Physical properties can be observed without attempting to change the identity of the substance.

D. Physical properties describe elements in the solid state rather than in the liquid or gas state.

Answers

Answer:

C

Explanation:

A Is false because physical properties can relate to any chemical substance.

B Is false because physical properties are apparent wether a chemical change has occurred or not.

C Is correct because physical properties can be observed without making a chemical change to the substance, chemical properties cause physical properties but a chemical change is not needed to observe a physical property.

D Physical properties describe compounds in all phases of matter.

A property that makes some objects float in water?

Answers

Answer:

Density

Explanation:

some objects are less dense so e.g balloons, they stand more chance of floating on water than other objects that have more density

5. Which organelle, found in plant and
animals cells, can store wastes and
protect the cell from contamination?

Answers

the answer would be VACUOLES

A brick has the mass of 555g and volume of 250cm3. what is the density of the brick​

Answers

Answer:

The answer is 2.22 g/cm³

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\[/tex]

From the question

mass = 555 g

volume = 250 cm³

We have

[tex]density = \frac{555}{250} = \frac{111}{50} \\ [/tex]

We have the final answer as

2.22 g/cm³

Hope this helps you

A golden nugget displaces 89.60 mL of water when submerged. If the density of gold is 19.32 g/cm² what is the mass of the nugget

Answers

Answer:

The answer is 1731.1 g

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

mass = Density × volume

From the question

density = 19.32 g/cm³

1 mL = 1 cm³

89.60 mL = 89.60 cm³

volume = 89.60 cm³

So we have

mass = 19.32 × 89.60 = 1731.072

We have the final answer as

1731.1 g

Hope this helps you

Definition of reactant

Answers

Noun

a substance that takes part in and undergoes change during a reaction.

If a sample of silver is reduced to the smallest possible particle of pure silver, which statement would most accurately describe the result?
A.The sample would be reduced to an atom of silver.
B.The sample would be reduced to molecules of silver.
C.The sample would be reduced to protons and neutrons of silver.
D.The sample would be reduced to electrons and protons of silver.

Answers

B because the sample is reduced

Answer the following questions from section 1.1. Everyone's ebook should work now, please use it. Again, to access your ebook, go to jway. Look for the red connectED McGraw Hill Education icon. Click it. Click the blue launch button on the book that pops up. Look for the green ebook button on the right of the page, click it. Now you can press the buttons on the left and right to navigate through the book. If you click the button in the far upper left corner that looks like pages on a book, this will give you a drop down menu of each section. Click the drop down arrow on unit 1. Click the drop down arrow on chapter 1. Scroll down and find the lesson 1.1 Earth's Interior. Now press the arrows to the left and right to flip through section 1.1.



Answer the following questions from 1.1.

1. What are the 3 layers of the earth?

2. In your own words, describe an earthquake.

3.What is the least dense and most dense layer of Earth, and why?

4. What are the 2 types of crust of Earth?

5.What are the 2 types of earthquake waves? Which waves are fastest?

6. What is an indirect observation?

7. What are the four layers of the mantle?

8. Why is the outer core liquid but the inner core solid?

Answers

1)The earth is made up of three different layers: the crust, the mantle and the core.

2) I think an earthquake is when the tectonic plates form together and progress movement which cause floor shakiness and everything falls.

3) Earth's interior layers are ordered by density. The densest layer is the solid metal inner core, the mantle is of intermediate density, and the least dense layer is the lithosphere, particularly the continental lithosphere.

4) Earth's crust is divided into two types: oceanic crust and continental crust.

5)Surface waves travel along the surface. There are two types of body waves: P-waves travel fastest and through solids, liquids, and gases; S-waves only travel through solids. Surface waves are the slowest, but they do the most damage in an earthquake.

6)Indirect observation involves the analysis of textual material generated either indirectly from transcriptions of audio recordings of verbal behavior in natural settings or directly from narratives.

7)The mantle is divided into several layers: the upper mantle, the transition zone, the lower mantle, and D” , the strange region where the mantle meets the outer core.

8)The outer core is not under enough pressure to be solid, so it is liquid even though it has a composition similar to the inner core. Sulfur and oxygen could be present in the outer core.

If I add 2 grams of sugar to 50 grams of water what should the mass of my
mixture be?

Answers

Answer:

[tex]m_{mixture}=52g[/tex]

Explanation:

Hello.

In this case, since your mixture is composed by sugar and water, its mass turns out:

[tex]m_{mixture}=m_{sugar}+m_{water}[/tex]

Whereas the mass of sugar is 2 g and the mass of water is 50 g, therefore, the result is:

[tex]m_{mixture}=2g+50g\\\\m_{mixture}=52g[/tex]

Best regards.

What charge does Co have in Cobalt (III) Chloride?

Answers

Answer:

+3

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). . In this compound, the cobalt atoms have a formal charge of +3.

Explanation:

Answer:

+3

Explanation:

(the roman numerals tells all)

how many moles of chlorine gas is contained in 4.81x10^24 molecules

Answers

Answer:

7.99 mol

Explanation:

Step 1: Given data

Molecules of chlorine gas: 4.81 × 10²⁴ molecules

Step 2: Calculate how many moles of chlorine gas corresponds to 4.81 × 10²⁴ molecules of chlorine gas

In order to convert molecules to moles, we will use Avogadro's number: there are 6.02 × 10²³ molecules of chlorine gas in 1 mole of molecules of chlorine gas.

4.81 × 10²⁴ molecules × (1 mol/6.02 × 10²³ molecules) = 7.99 mol

Halley’s Comet is a comet that passes close to earth every 75 years. Based on the passage , which gravitational attraction has the most influence on the movement of this astronomical object?

Answers

Answer:

Attraction between the comet and the Sun

Explanation:

Metalloids exhibit a combination of localized and delocalized bonding. How does this relate to the properties of metalloids?

Answers

Answer:

The combination of localized and relocated connections is what allows the metalloid to be a transitional element between a metal and a non-metal. With that, it manages to be a solid and shiny element, but brittle.

Explanation:

A metalloid is also called ametal and has intermediate characteristics between metal and non-metal elements. they are characterized as solid, shiny, brittle and good idolizers of temperature and electricity, however, they assume the characteristics that metals present in relation to conductivity when they are heated. This is because the increase in temperature makes the electrons connected by weak bonds become free, making them semiconductors.

If it requires 67 J of heat to raise the temperature of a piece of iron by 5.0°C, calculate the mass of the iron. The specific heat of iron is 0.46 J/g·°C.

Answers

Explanation:

E= m.c. delta T

67 = m . 0.46. 5

m = 67/(0.46*5)

m = 67/2.3

m= 29.13 g

How many moles are in 3.48 x 1024 particles of lithium ?

Answers

Answer:

5.78 mol Li

Explanation:

Step 1: Define

Avagadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Step 2: Use Dimensional Analysis

[tex]3.48(10)^{24} \hspace{3} particles \hspace{3} Li(\frac{1 \hspace{3} mol \hspace{3} Li}{6.02(10)^{23} \hspace{3} particles \hspace{3} Li} )[/tex] = 5.78073 mol Li

Step 3: Simplify

We have 3 sig figs.

5.78073 mol Li ≈ 5.78 mol Li

Rational numbers are?​

Answers

✅The racial numbers are all the numbers that can represent as the quotient of two numbers enter or, more precisely, an entity and a natural positive; The term "racial" refers to a fraction or part of a whole.

IamSugarBee

what will happen to the 5 pesos stack coins when you hit the coin at the bottom?why is this so?

Answers

Answer:

The correct answer is "The 5 pesos stack coins will remain at its place".

Explanation:

According to Newton's first law "every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force". In this case, hitting a single 5 pesos coin at the bottom of the stack does not represent an external force with enough energy to move the stack considerably. Therefore, the 5 pesos stack coins will remain at its place since it tends to remain at rest as any other object.

Select all the statements that correctly describe the procedure for drawing a Newman projection.
A. There will be 3 lines drawn directly to each C atom.
B. A dot drawn at the center of the circle represents the front C.
C. A circle is used to represent the back carbon.
D. A Newman projection considers one C-C bond at a time.
E. The bonds for both the front and back C atoms are drawn as lines meeting at the center of the circle.

Answers

Answer:

A dot drawn at the center of the circle represents the front C.

A circle is used to represent the back carbon.

There will be 3 lines drawn directly to each C atom.

Explanation:

A Newman projection is an alternative way to view a molecule instead of the sawhorse projection.

In a Newman projection, the front atom is shown as a dot at the center of a big circle while the back atom is shown as a circle. Three lines indicating binds to substituents are drawn to each carbon atom directly.

This method of representation of molecules was introduced by Melvin Spencer Newman in 1952 to partly replace Fischer projections. Fischer projections did not adequately show the conformer of a compound.

You are given a bottle of impure CoSO4 7H2O which is thought to be 74.4% by weight CoSO4 7H2O. You propose to run your own analysis to find out. What weight of sample should you take to get 0.345 g of BaSO4?

Answers

Answer:

ggv DDT gnrh h

Explanation:

assssssssassfggg

Shown here is the chemical formula for ammonia.
N H
NH,
The 3 in the chemical formula for ammonia means that there are
three-
А
atoms of ammonia
B
molecules of ammonia.
с
atoms of hydrogen in each molecule.
D
atoms of nitrogen in each molecule.

Answers

Answer:

Explanation: Ammonia is made out of one nitrogen and three hydrogen atoms. Its structure is tetrahedral. Ammonia is used in nitric acid production, as a fertilizer, and a cleaning solution.

NH3, normally found as a gas, it is caustic and harmful in longterm exposure. NH3 has a boiling point of -33 Celsius, and must be stored under pressure, or at low temperatures.

Ammonia is regulated in the United States as a substance that is a non-flamable gas. However, it still meets the definition of a material that is toxic by inhalation and requires a hazardous safety permit.

Ammonia is usually a gas with a pungent odor. Ammonia used commercially is usually named anhydrous ammonia. An exposure to a very high concentration of ammonia could result in lung damage and death

Ammonia is a gas with a strong smell. Its chemical formula is NH3. If exposed to a very high concentration of ammonia, it can cause lung damage and death.

Ammonia, NH3, is a compound that is has a strong smell. Even though the gas helps the nutrition of our planet, it can cause serious problems to our health.

Ammonia, NH3, is a pungent gas. It is colorless, and used to manufacture fertilizers and

The three in the chemical formula for ammonia means that there are three atoms of hydrogen in each molecule. The correct option is c.

What is ammonia?

Ammonia is a material that is classified in the US as a non-flammable gas. It nevertheless satisfies the criteria for a substance that is dangerous when inhaled and necessitates a hazardous safety permit.

Three hydrogen atoms and one nitrogen atom combine to form ammonia. It has a tetrahedral structure. Ammonia is a fertilizer, a cleaning agent, and is used in the manufacturing of nitric acid.

NH3 is typically found as a gas and, when inhaled over time, is corrosive and dangerous. NH3 must be stored under pressure or at low temperatures because it has a boiling point of -33 degrees Celsius.

Therefore, the correct option is c. atoms of hydrogen in each molecule.

To learn more about ammonia, refer to the below link:

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Using the evidence provided, generate a pattern that describes the chemical reactivity of metals.


A

As you go from left to right, reactivity of metals increases. As you go down in a group, reactivity of metals increases.


B

As you go from left to right, reactivity of metals increases. As you go down in a group, reactivity of metals decreases.


C

As you go from left to right, reactivity of metals decreases. As you go down in a group, reactivity of metals increases.


D

As you go from left to right, reactivity of metals decreases. As you go down in a group, reactivity of metals decreases

Answers

Answer:

B)As you go from left to right, reactivity of metals increases. As you go down in a group, reactivity of metals decreases.

Explanation:

reactivity of metals can be explained as how it can easily lose electron, i.e oxidize as well as reaction with non-metals.

There are factors that influence the reactivity of metals such as

1)atomic radius

2)nuclear charge

3)shielding effect

4) The sublevel arrangement of electrons

In the periodic table,the group 1, known as alkali metals, are the most reactive metals

Therefore, as we from left to right, reactivity of metals increases. As we move down in a group, reactivity of metals decreases.

The part of a voltaic cell allows ions to move between half cells so that charge doesn't build up is the ?
A. anode.
B. cathode
C. voltmeter.
D. salt bridge.

Answers

I believe the answer is salt bridge! Hope this helps.

I NEED HELP ASAPPPPP!!!!!!!

Objects with similar volume always have the same mass.

True or false?

Answers

The answer is true !!!!!

Use the perfodic table to fill in the table below.
Element
Group Name
Charge
# of Valence
Electrons
# of Energy
Levels
One Element
with similar
Properties
Boron
Akaline Earth
Metals
Fluorine
1
5
Tin
Sulfur
Krypton
3
Arsenic
lodine
Potassium
5
Thallium

Answers

Answer:

charge

# of Valence

Electrons

# of Energy

Explanation:


Which of these is most likely the cause of a father and son having almost identical-sounding voices?
O learned behaviors
O environmental conditions
O inherited characteristics
O instinctive characteristics

Answers

It would be C. inherited characteristics
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