A fifth-grade science class puts half of a white tablet in a test tube with 10 milliliters (mL) of water at 21°C (70°F). The tablet bubbles rapidly for three minutes until it is gone. Students record the final temperature at 20°C (68°F). Which choice best identifies evidence that a chemical reaction occurred?

Answers

Answer 1

Answer:

i think it table broke in half

Explanation:

Answer 2

Answer: it would be change in water temperature

Explanation: because the change in the water is the temperature and its is

evaporation


Related Questions

24 * All the following hormones help in the appearance of beard in the adult male,
except​

Answers

Answer:21

Explanation:sadadasdasdad

Answer:

Facial hair growth is largely propelled by testosterone, a hormone. Testosterone levels can vary. For men between 19 and 38, the normal range is 264 to 916 nanograms per deciliter

An initial substance used in a chemical reaction is called a
1.
chemical reaction
2.
reactant
3.
product
4.
new substance

Answers

the answer is reactant
The initial substance is called reactants.

Each year, due to growing population and energy demands, the United States faces increasing dependency on conventional fossil fuels. However, in the past few decades renewable energy has begun to expand in both residential and commercial sectors of the United States.
a)
i. The U.S. uses roughly 4.0 million Gigawatt-hours per year in electricity. Currently 50% of our electricity comes from coal. If every 1.0 kilowatt-hour of coal burned releases 2 lbs. of carbon dioxide, how much carbon dioxide is released from burning coal for electricity each year in the US?
ii. What will be the reduction of carbon dioxide entering the atmosphere each year if coal usage could be reduced by 15% by utilizing solar energy?
iii. List and discuss TWO advantages to using wind energy to generate electricity.
b) Identify and describe a type of passive OR active solar heating method.
c) Give one advantage and one disadvantage to the method you described above in question b).

Answers

Answer:

A) (i) 4*10^12 Ibs , (ii) 600 * 10^9 Ibs  

(iii)

Wind energy is a clean energy : this is because there is no consumption of fossil fuels when using wind energy to generate electricityWind energy is a renewable energy : wind is reusable and it is always available for use

B) The use of  bricks or stone that can absorb the solar heat easily when the sun rays heat them up and this solar heat absorbed . is a typical example of a passive solar heating system.

C) Advantage : It is mostly cost free

disadvantage : there is no storage mechanism

Explanation:

A) Given that U.S uses roughly 4 million Gigawatt-hours per year in electricity and 50% of the electricity comes from coal

i) Determine how much carbon dioxide is released from burning coal each year

since 50% of electricity comes from coal

The Total energy produced by coal =2*10^12 Kw-h. also

1.0 kilowatt-hour of coal burned releases 2 lbs.

hence the Total amount of Carbon dioxide released from burning coal each year = 2 * 2 * 10^12 =  4 * 10^12 Ibs  

ii) Determine the reduction of carbon dioxide entering the atmosphere each year if coal usage could be reduced by 15% by utilizing solar energy

= 15% 0f 4*10^12

reduction of coal usage by 15% = 600 * 10^9 Ibs hence the amount of coal entering the atmosphere is reduced by 600 * 10^9 Ibs

iii) Advantages of using wind energy to generate electricity

Wind energy is a clean energy : this is because there is no consumption of fossil fuels when using wind energy to generate electricityWind energy is a renewable energy : wind is reusable and it is always available for use

B) Passive solar heating system

The use of  bricks or stone that can absorb the solar heat easily when the sun rays heat them up and this solar heat absorbed . is a typical example of a passive solar heating system.

C) advantage and disadvantage of solar heating system

Advantage : It is mostly cost free

disadvantage : there is no storage mechanism

Splitting of a signal in a proton NMR spectrum tells us the number of chemically non-equivalent hydrogens in the immediate vicinity of the hydrogen giving the signal.

a. True
b. False

Answers

Answer:

True

Explanation:

In a given molecule protons in the same chemical environment absorb at the same applied field strength; whereas protons with different chemical environments absorb at different applied field strengths.

A set of protons in the same chemical environment are said to be equivalent. Hence, the number of signals in the NMR spectrum tell us the number of sets of equivalent protons present in the molecule.

Splitting of a signal in a proton NMR spectrum tells us the number of chemically non-equivalent hydrogens in the immediate vicinity of the hydrogen giving the signal.

How does photosynthesis affect food chains and food webs?

Answers

Answer:

Throughout the clarification section, the description of the situation is summarized.

Explanation:

Plant species mostly with such as photosynthesis have been providing us with just the very first food processing commodity.

They are always the component of the environment, the meals they consume, our clothing, and sometimes even our appliances, and plenty of other components or consumables. Seedlings often extract the greenhouse effect from either the environment, offer additional shelter for far too many species.

please help me ill give you 9 points for your help

Answers

Answer:

it should be Robert Boyle

Answer:

Robert Boyle

Explanation:

he relationship between the volume and pressure of a given amount of gas at constant temperature was first published by the English natural philosopher Robert Boyle over 300 years ago.

what is the force on a 1,000 kg elevator that is falling freely at 9.8 m/s2​

Answers

Answer:

The only force on it is its weight, w=9800N

Explanation:


14.) Analyze: What pattern do you see?

Answers

You need to add an image
I don’t see an image to see the pattern can your try again ???

1.24 moles of magnesium arsenate are dissolved in 1.74 kg of solution. Calculate the molality of the solution.

Answers

Answer:

Molality of the solution = 0.7294 M

Explanation:

Given:

Number of magnesium arsenate = 1.24 moles

Mass of solution = 1.74 kg

Find:

Molality of the solution

Computation:

Molality of the solution = Mole of solute / Mass of solution = 1.74 kg

Molality of the solution = 1.24 / 1.7

Molality of the solution = 0.7294 M

Why is the combined gas law the most practiced gas law

Answers

The combined gas law allows you to derive any of the relationships needed by combining all of the changeable peices in the ideal gas law: namely pressure, temperature and volume

The combined gas law allows you to derive any of the relationships needed by combining all of the changeable peices in the ideal gas law: namely pressure, temperature and volume.

Pleas answer ASAP!! If the empirical formula of an organic compound is CH2O then the molecular mass of the compound could be? 15 grams 45 grams 60 grams 135 grams

Answers

Answer:

uhh 60??

Explanation:

The molecular mass of the compound could be 60g, the correct option is option c among all the given options.  

What is  molecular mass?

The weight of a molecule is measured by its molecular mass. Atomic weight is another name for it. It usually involves multiplying the total mass of all the atoms in the molecule by the overall number of the element's atoms.

For instance, there are two hydrogen atoms and one oxygen atom in water. The atomic weight of oxygen multiplied by two or more to get the typical hydrogen atomic mass gives the water molecule its mass. The atoms that make up the molecule are what determine an element's molecular mass.

Empirical formula is CH[tex]_2[/tex]O

Mass of Empirical formula =12+12+16=30g

Vapour density = Molar mass of compound/2

30= Molar mass/2

Molar mass of compound =60g

Therefore,  the molecular mass of the compound could be 60g, the correct option is option c among all the given options.  

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which properties represent a metal ( select all that apply )
a. malleable
b. shiny
c. dull
d. brittle
e. good conductors

Answers


Malleable, shiny and good conductors
A B E

Can someone answer this question please. Is this a physical change or chemical change?

Answers

Answer:

Chemical

Explanation:

the acid is a chemical and the molecules are getting torn apart by the acid

A student says that since the atomic theory is just a theory, it should not be considered useful. Which statement best argues against the student's opinion? (2 points) Scientific theories change over time. Scientific theories are the results of many experiments and observations. Scientists often do not agree about specific details of scientific theories. Scientists often propose competing theories. Scientific theories do not become Scientific Laws.

Answers

Answer:

Scientific theories are the results of many experiments and observations.

Explanation:

I think this is ti sorry if I'm wrong :|

Which element easily loses one electron to form a positive ion? (AKS 1c/DOK 1)

A.
Nitrogen (N)

B.
Bromine (Br)

C.
Potassium (K)

D.
Magnesium (Mg)

Answers

Answer:

Potassium

Explanation:

It's in group 1 in the periodic table of elements

The octane rating of gasoline is a relationship of the burning efficiency of the given gasoline mixture to the burning efficiency of octane (C8H18). Like most hydrocarbons, octane reacts with oxygen gas to produce carbon dioxide and water. The unbalanced equation for this reaction is

Answers

Answer:

C₈H₁₈(l) + O₂(g) ⇒ CO₂(g) + H₂O(l)

Explanation:

Let's consider the unbalanced equation for the combustion reaction of octane.

C₈H₁₈(l) + O₂(g) ⇒ CO₂(g) + H₂O(l)

We can begin balancing H atoms by multiplying H₂O by 9, and C atoms by multiplying CO₂ by 8.

C₈H₁₈(l) + O₂(g) ⇒ 8 CO₂(g) + 9 H₂O(l)

Finally, we get the balanced equation by multiplying O₂ by 12.5.

C₈H₁₈(l) + 12.5 O₂(g) ⇒ 8 CO₂(g) + 9 H₂O(l)

Answer:

The coefficents will be 2, 25 --> 16, 18

Explanation:

What will happen to bring the substance from a solid to a gas?


The substance will lose pressure.


Energy will be added.


Energy will be taken away.


The substance will lose volume.

Answers

Answer:

B) Energy will be added

Explanation:

I just took the test...

Where does the light that makes the moon visible come from?
A. another planet
B. the moon
C. Earth
D. the sun

Answers

The answer is D. the sun.

Explanation: At night, the moon blocks the sun, while absorbing the light of the sun as-well.
D. The sun is the correct answer

Under identical conditions, separate samples of O2 and an unknown gas were allowed to effuse through identical membranes simultaneously. After a certain amount of time, it was found that 7.88 mL of O2 had passed through the membrane, but only 3.69 mL of of the unknown gas had passed through. What is the molar mass of the unknown gas

Answers

Answer:

146.5g/mol

Explanation:

The volume of  gas effused is directly proportional to the square root of its relative molecular mass.

Let the volume of oxygen gas be V1

Let the volume of the unknown gas be V2

Let the molar mass of oxygen be M1

Let the molar mass of the unknown gas be M2

V1/V2 =√M2/M1

7.88/3.69 = √M2/32

2.14 = √M2/32

(2.14)^2 = M2/32

4.58 = M2/32

M2 = 32*4.58

M2 = 146.5g/mol

CH4(g) gas reacts with F2(g) to produce CH3F(g) and HF(g) .

a) A particulate representation of F2(g) is shown above its formula in the equation below. Using the key provided, draw particulate representations of CH4(g) and the two product molecules of the reaction above their formulas in the equation.

Answers

Answer:

I am looking for this as well. Can someone please help!

Explanation:

Answer:

here you go :)

Explanation:

i know it isn't pretty but i hope you use it well

Organelles_____are specialized structures that carry out particular jobs and functions?

Answers

Answer:

Cell or cellular

Explanation:

Heyy!! Not sure, but cell and cellular are the same. They carry out particular jobs and functions. Hope this helps, thank you :) !!

The surface area of a star can be estimated based on the stars

Answers

size (length+width) approx.

Where is ocean water the densest?

1.The surface
2.The bottom
3.The middle
4.Lake Michigan

Answers

Answer:

your answer should be the bottom

sorry if im wrong

Explanation:

What force on Earth can affect the pull of gravity?

Answers

Objects with more mass have more gravity. Gravity also gets weaker with distance. So, the closer objects are to each other, the stronger their gravitational pull is. Earth's gravity comes from all its mass.

Answer:

the moon or the sun

Explanation:

What is always true of a strong acid?
A. It does not dissociate at all in solution.
B. It has not been diluted with water.
C. It has more than one hydrogen atom.
D. It dissociates completely in solution.

Answers

Considering the definition of strong acid, it dissociates completely in solution (option D) is always true of a strong acid.

Definition of strong acid

An acid that completely dissociates in solution at constant temperature and pressure is called a strong acid.

In other words, strong acids are completely ionized, that is, in the ionization process they are completely transformed into cations or positive ions and anions or negative ions.

Strong acids are characterized by being very corrosive and have the ability to conduct electrical energy efficiently.

Examples of strong acids are hydrochloric acid (HCI) and hydrobromic acid (HBr).

Summary

It dissociates completely in solution (option D) is always true of a strong acid.

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Which are characteristics of electromagnetic waves? Check all that apply.
travel in straight lines and can bounce off surfaces
travel through space at the speed of light
travel only through matter
travel only through space
can bend around objects
move by particles bumping into each other
move by the interaction between an electric field and a magnetic field

Answers

-travel in straight lines and can bounce off surfaces
-travel through space at the speed of light
-can bend around objects
-move by the interaction between an electric field and a magnetic field

The characteristics of electromagnetic waves  are that they  travel in straight lines and can bounce off surfaces,travel through space at  speed of light,can bend around objects,move by interaction between electric field and magnetic field.

What are electromagnetic waves?

The electromagnetic radiation consists of waves made up of electromagnetic field which are capable of propogating through space and carry the radiant electromagnetic energy.

The radiation are composed of electromagnetic waves which are synchronized oscillations of electric and magnetic fields . They are created due to change which is periodic in electric as well as magnetic fields.

In vacuum ,all the electromagnetic waves travel at the same speed that is with the speed of air.The position of an electromagnetic wave in an electromagnetic spectrum is characterized by it's frequency or wavelength.They are emitted by electrically charged particles which undergo acceleration and subsequently interact with other charged particles.

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One mole (mol) of ethanol (C2H60) has a mass of 46.0684 g.
How many moles of ethanol are in an 18.0 g sample?

Need to see how the calculation was done.

Answers

Answer:

the number of moles of ethanol is 18 g sample is 0.390 mol

Explanation:

The computation of the  number of moles of ethanol is 18 g sample is shown below:

= Mass of ethanol sample ÷ molar mass of ethanol

= 18 g ÷ 46.064=84 g

= 0.390 mol

Hence, the number of moles of ethanol is 18 g sample is 0.390 mol

what causes deep ocean currents to flow

Answers

Answer:Deep ocean currents (also known as Thermohaline Circulation) are caused by: ... The sinking and transport of large masses of cool water gives rise to the thermohaline circulation, which is driven by density gradients due to variations in temperature and salinity. The earth's rotation also influences deep ocean currents.

Explanation:

Which word best describes gamma rays?

A)Weak
B)Destructive
C)Visible
D)Harmless

Answers

Answer:

Explanation:

Destructive :D

According to the position of gamma rays in electromagnetic spectrum,the word which best describes gamma rays is destructive as they have high energy.

What is electromagnetic spectrum?

The electromagnetic spectrum consists of electromagnetic radiation  which consists of waves made up of electromagnetic field which are capable of propogating through space and carry the radiant electromagnetic energy.

The radiation are composed of electromagnetic waves which are synchronized oscillations of electric and magnetic fields . They are created due to change which is periodic in electric as well as magnetic fields.

In vacuum ,all the electromagnetic waves travel at the same speed that is with the speed of air.The position of an electromagnetic wave in an electromagnetic spectrum is characterized by it's frequency or wavelength.They are emitted by electrically charged particles which undergo acceleration and subsequently interact with other charged particles.

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correct name for PtO.

Answers

Answer:

It may stand for 'Paid Time Off'

Explanation:

I need more context but that's probably it.

Answer:

gracias

Explanation:

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