How many hydrogen atoms are in 2h2+02—2h20?


Answer 1

Answer: Two hydrogen atoms


A water molecule (formally known as dihydrogen monoxide) is composed of two hydrogen atoms and one oxygen atom. But you can't simply take two hydrogen atoms and stick them onto an oxygen atom. The actual reaction to make water is a bit more complicated: 2H2 + O2 = 2H2O + Energy.

Related Questions

Identify the choice that best completes the statement or answers the question.
Banana slugs live on the ground in moist forests of the Pacific Northwest. They consume and
break down a variety of materials, including small dead animals and rotting leaves. Which
term describes banana slugs?
O carnivores
O consumers
O decomposers
O producers


The answer would be decomposers

Name for each compoud
4 H202


1. Carbon monoxide
2. Sulfuric acid
3. Calcium carbonate
4. Hydrogen peroxide
5. Sodium fluoride
hope this helps (:

How to separate these pure substance?if it is not possible, please write cannot be separate

Carbon Dioxide



Oxgen- cannot be separated

Water - chemical change

Gold - cannot be separated

Carbon Dioxide - chemical change

Carbon​ - cannot be separated


A pure substance, which can either be an element or a compound, contains only one type of such element or compound. In opposition to a mixture, pure substances cannot be separated by physical means.

- Elements as a pure substance cannot be separated because it contains only one type of atom. However, compounds contain two or more types of atoms, and hence, can only be separated into its individual atoms via chemical means.

In this question, oxygen (O2), Gold (Au) and carbon (C) are all elements and hence cannot be separated. Carbon dioxide (CO2) and water (H2O) are compounds because they contain two different atoms respectively, hence, can be separated into individual atoms.

Do 2. A student determines that there are 1.3 x 1025 molecules of an unknown
substance in a 968 g sample. Which compound most likely represents this
unknown substance?



The correct option is;



The given information are;

The number of molecules in the substance = 1.3 × 10²⁵

The mass of the substance = 968 g

Therefore, we have;

The number of molecules in one mole of a substance = 6.02 × 10²³

The number of moles present = (1.3 × 10²⁵)/(6.02 × 10²³) ≈ 21.595 moles

Therefore, 968 g = 21.595 moles

1 mole = 968/21.595 = 44.826 g

The mass of one mole of the substance = 44.826 g

Therefore the mass of one mole of the substance is closely related to the mass of one mole of CO₂ which is 44.01 g/mol.  

The correct option is CO₂

The calculation is as follows:

The number of molecules in one mole of a substance should be = 6.02 × 10²³


The number of moles present is

= (1.3 × 10²⁵)/(6.02 × 10²³)

≈ 21.595 moles


1 mole = 968/21.595 = 44.826 g

The mass of one mole of the substance = 44.826 g

So,  the mass of one mole of the substance is closely related to the mass of one mole of CO₂ i.e.  44.01 g/mol.  

Learn more:

what is the solution to the equation below rounded to the correct number of significant figures? 4700 L - 281.4 = _____ L



I went over this problem multiple times and I finally found the soultion

The concept of significant figures are mainly used by scientist and engineer to know the significance of digits in a measurement. Therefore, 4400L is the solution to the equation rounded to the correct number of significant figures.

What is significant figures?

Significant figures are the figures that indicate the degree of accuracy of a value. It tells about the precision of a value. It gives an idea about the digits that are necessary to indicate the experimental value.

Rules for counting significant figures are:

Number between 1 to 9 is always significant

Zeroes after a number has got no significance

Zeroes before a number has got no significance

Zeroes between number has got significance

4700 L - 281.4 =4400L

Therefore, 4400L is the solution to the equation rounded to the correct number of significant figures.

To learn more about Significant figures, here:


Fill in the blanks: a substance that undergoes a ______ change will always result in something new that has ________ properties than what it started out as. A- physical and different. b- physical and same. C-chemical and different. D chemical and same


The answer is C. When an object undergoes a physical change, its properties are different.

Is burning the glass plate is physical or chemical change?


This is a physical change because you are burning the glass plate and that changes the plate. I hope this helps. HAVE A GREAT DAY
This is a chemical reaction because stour adding heat, you are chemically doing something, physical is when you point out the obvious using your five senses. Touching it to feel how soft on object is, or what colour (vision). You are adding heat which is chemical.

Write the correct electron configurations for the following:
• Na (atomic # 11)
• Fe (atomic # 26)
• As (atomic # 33)
• F (atomic #9)
• Co (atomic #27)
• Ag (atomic # 47)
• K (atomic # 19)
• Cu (atomic # 29)
• Si (atomic # 14)





atomic 33 because it what what sence

Na- 1s^2 2s^2 2p^6 3s^1

Fe- 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^6

As- 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^3

F- 1s^2 2s^2 2p^5

Deciding that she was thirsty, Ms. Smith decided to mix up some lemonade using 2 tablespoons of lemonade, and 2 cups of water. What is the solute and solvent?



solute is the substance being dissolved so that is the 2 tablespoons of lemonade and the 2 cups of water is the solvent.

Calculate the density of helium if a balloon with a capacity of 5.00 L holds 0.890 g.




Density is m/V. Also, 1 liter = 1000 [tex]cm^3[/tex]. So, we get 0.890/(5*1000) = [tex]1.78*10^{-4}[/tex] g/cm^3. You can convert this to kg/m^3 as well by multiplying it by 10. Depends which one you want.

The ratio of the mass in grams and volume in cubic meters gives the density. The density of 0.80 gm helium is 1.78 × 10 ⁻⁴ g/cm³.

What is density?

Density is the amount or the number of entities that can be contained in an area. It is denoted by ρ and is calculated as,


Mass = 0.890 gm

Volume = 5000 cm³

ρ = Mass ÷ Volume

= 0.890 ÷ 5000

= 1.78 × 10 ⁻⁴ g/cm³

Therefore, 1.78 × 10 ⁻⁴ g/cm³ is the density of helium.

Learn more about density here:


by . Figure the density of the liquid in each beaker: The mass and volume of each liquid have been given in Table 1. Using the formula for density and a calculator, figure the density of each liquid and record it in the density column of Table 1. Round and write your answer out to the nearest hundredth. (This means you will have two numbers after the decimal point.) Don't forget to write the units!!!!!! (Hint: The formula was the answer to #2 on the front page.)​



Well what are the numbers but ik that it ius 5


Which pair of symbols represents nuclei with the same number of neutrons?
A. 56 Co and 580
B. 57Co and 58Ni
c. 57Fe and 58 Ni
D. 57Mn and 57Fe





Mass number  = number of neutrons + number of protons

Atomic number is the number of protons in the nucleus.  

58Ni   : 58 is the number of neutrons + number of protons

atomic number of Ni is 28.  Thus,  58 -28 = 30 neutrons

57Co ;  57 is the number of neutrons + number of protons

number of Co is 27. Thus, 57 – 27  = 30 neutrons

what is atomic radius​



The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding shells of electrons. Since the boundary is not a well-defined physical entity, there are various non-equivalent definitions of atomic radius. Three widely used definitions of atomic radius are: Van der Waals radius, ionic radius, and covalent radius

Please help!!!
When 38 g of a metal at 92 °C is added to
43 g of water at 22°C, the temperature of the
water rises to 30°C. What is the specific heat
capacity of the metal? Assume no heat was
lost to the surroundings.

Answer in units of
J/g degrees C


The specific heat  capacity of the metal : 0.610 J/g° C  

Further explanation  

The law of conservation of energy can be applied to heat changes, i.e. the heat received/absorbed is the same as the heat released  

Q abs = Q received  

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  

∆T = temperature difference, ° C / K  

∆T = T(final temp) - T(initial temp)

mass of metal = 38 g

T initial metal = 92 °C

mass of water = 43 g

T final water = 30  °C

T initial water = 22°C

c water = 4.18 J/g° C  

Heat absorbed by water

[tex]\tt Q=m.c.\Delta T\\\\Q=43\times 4.18\times (30-22^oC)\\\\Q=1437.92~J[/tex]

the specific heat  capacity of the metal

Q water = Q metal

[tex]\tt 1437.92=38\times c\times (92-30)\\\\c=0.610~J/g^oC[/tex]

will give brainlliest

Which noble gas is closest to sulfur, S, on the periodic table? What has to happen for a sulfur atom in order to have an electron arrangement similar to the nearest noble gas?


Answer: argon

What must happen to a sulfur atom in order for it to have an electron arrangement similar to that of a noble gas? Answer: The noble gas closest to sulfur is argon. A sulfur atom gains two electrons to have an electron arrangement similar to that of argon.


A cube of metal has a mass of 5.05 x 10°g and its density is known to be 12.77 g/mL, what is the volume of this metal?
A 395.5 mL
B. 2.529 mL
C. 63,910 mL
D. 64.48 ml




option A is correct

Identify the heterogeneous mixtures.
Group of answer choices



vegetable soup

apple juice

trail mix



One thing to remember is homo=same/pure and hetero=different

so heterogeneous mixture is would be salad, vegetable soup, trail mix and brass.

this is because salad, vegetable soup, trail mix, and brass have a lot components and they’re not pure.

Hopefully i could help!!

how many picoliters are in 3.16 mL



3.16×10⁹ pL


Given data:

Volume in mL = 3.16

Volume in picoliters = ?


Picoliter and milliliters are units of volume. Milliliter is greater unit than picoliter.

1 mL = 10⁹ pL

Now we will convert the 3.16 mL into pL.

3.16 mL × 10⁹ pL/ 1 mL

3.16×10⁹ pL

Planets A and B are both the same size, but planet B has three times the mass of planet A. How does the weight of an object compare on the two planets?

Choose the correct answer.

The weight of an object is the same on both planets.

The weight of an object is three times larger on planet A.

The weight of an object is three times larger on planet B.

The weight of an object will depend on more factors than just the weight and size of the planet.



The answer is d


explanation of atomic radius​


Ah yes.

The atomic radius is basically the distance between the nucleus of the atom and the outermost electron in the farthest orbital of the atom. The more bigger the atomic radius , the less powerful is the force that holds together the nucleus and its electrons.

The first chemists, philosophers like, Aristotle were from which country?





aristole was particularly from stagria, greece. but most early philosophers are from greece

with of the following describe a chemical change

a) a metal fork was melted

b) a metal fork was cut in half

c) a metal fork became bent

d) a metal fork became rusted​





Rusting is a chemical change that occurs due to oxygen.


d i had this your welcome

when heat is added to a substance describe how the molecules are affected?



the molecules and atoms start to vibrate faster so basically the object starts to expand because the space between atoms increases :)

after eating an apple and levaing it on top of the table. what will happend to the color of the inner part of the apple? what makes the color of the apple change​



Answer Below


When you leave an apple on a table outside it will turn brown. This happens because when you cut an apple, you are exposing it's insides to the oxygen in the air. This causes the PPO (polyphenol oxidase) enzyme in the apple's flesh to oxidize the polyphenols, turning them into some other brown colored products. Hence, the color change.


brown i can't explain because its a matter of the atoms in the apple mixing with the air and apple is made with nitrogen

Radon-222 is an alpha emitter with a half life of 3.82 days.

1. What is the mass number of the daughter isotope?
2. What is the element symbol of the daughter isotope?
3. What is the atomic number of the daughter isotope?​


The daughter isotope (a decay product): Polonium (Po)

Further explanation

Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,  

alpha α particles ₂He⁴ beta β ₋₁e⁰ particles gamma particles γ positron particles ₁e⁰

Radon-222 emits alpha α particles ₂He⁴  , so the atomic number decreases by 2, mass number decreases by 4


[tex]\tt _{86}^{222}Rn\Rightarrow _{84}^{218}+_2^4He[/tex]

1. The mass number of the daughter isotope = 218

2 and 3. If we look at the periodic system, the element with atomic number 84 is Polonium (Po)

If an animal is placed into a sealed container for a short time, the oxygen level will
A. decrease and the carbon dioxide level will increase.
B. decrease and the carbon dioxide level will decrease,
C, increase and the carbon dioxide level will increase.
D. decrease and the carbon dioxide level will stay the same.
E increase and the carbon dioxide level will decrease.





Animals take in oxygen and convert it into carbon dioxide therefore the oxygen levels will decrease and the carbon dioxide levels will increase

If an animal is placed into a sealed container for a short time, the oxygen level will:  decrease and the carbon dioxide level will increase.

What happens to oxygen level inside a container:

The oxygen held inside the space is quickly being consumed by the freight or because of rusting inside a space, and that encased spaces must consistently be treated as perilous. And the carbon dioxide levels on the other hand will increase.

It will not take a long time for an animal to survive under these conditions.

Thus. option A is correct.

Find more information about Oxygen here:

348 g of water starting at 4.0°Celsius is heated until his temperature is 37°Celsius. Calculate the amount of heat energy needed to cause this rise in temperature




48.049 kJ or 48049 J


Hello again.

So we know the formula [tex]q = mc\Delta t[/tex]. c is the heat capacity but this time, it is not given. However, water has a very well known heat capacity which is 4.184 J/(g°C). This is in fact the number we refer to a calorie which is the amount of energy you burn that can raise the temperature of 1g of water by 1°C. So, plugging in values, you get the above. But double check if I am wrong.

The amount of heat energy needed to cause this rise in temperature is 48.049 kJ or 48049 J.

What is heat energy?

Heat is the energy that moves from one body to another when temperatures are different. Heat passes from the hotter to the colder body when two bodies with different temperatures are brought together.

A given amount of matter's heat capacity is the amount of energy needed to raise its temperature by one degree Celsius.

The heat energy will be calculated by the formula

Q = m•C•ΔT

Where c is the heat capacity.

The m is the mass

T is the time

Mass is 348 grams

Temperature is 37°C

The change in temperature is 4.0°C to 37°C

The heat capacity of water is 4.184

Q = 348 x 4.184 x -33 = 48049.056.

Therefore, the amount of heat energy needed is 48.049 kJ or 48049 J.

Learn more about heat energy, here:


What is the mass, in grams, of 0.450 moles of Sb?



54.9 g


0.450 mol x 122g/mol

Relative and average atomic mass both describe properties of an element related to its different isotopes. Out of these two Relative atomic mas is more accurate. Therefore, 54.9 g is the mass in grams of 0.450 moles of Sb.

What is mass?

Mass defines the quantity of a substance. It is measured in gram or kilogram. Average mass is the mass of atoms of an element that are isotopes. It can be calculated by multiplying mass of a isotope to natural abundance of that isotope.

Average atomic mass = (mass of first isotope× percent abundance of first isotope)+(mass of second isotope× percent abundance of second isotope)

Mass of  Sb= number of moles of  Sb ×Molar mass of  Sb

=0.450 mol x 122g/mol

=54.9 g

Therefore, 54.9 g  is the mass in grams of 0.450 moles of Sb.

To learn more about mass, here:


A substance can change into a new kind of molecule when:



Chemical changes cause a substance to change into an entire substance with a new chemical formula. Chemical changes are also known as chemical reactions. The “ingredients” of a reaction are called reactants, and the results are called products.

Hope it helps

express the answer to each of the following calculations in scientific notation with the correct number of significant figures: 45.0 x 270


Answer: 1.215 × 10^4  i think


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