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The electron dot diagram for an element shows the valence electrons for the element. Oxygen is in group 16/VIA, so it has six valence electrons. Draw the symbol for oxygen. Then place one dot at each side of the symbol.

Answer:

[tex]\boxed {\boxed {\sf 24.2624 \ g}}}[/tex]

Explanation:

Density measures mass per volume. The volume is

[tex]\rho=\frac{m}{v}[/tex]

The density of limestone is 2.72 grams per cubic centimeter. We have a piece of limestone with a volume of 8.92 cubic centimeters.

Substitute the values into the formula.

[tex]2.72 \ g/cm^3=\frac{m}{8.92 \ cm^3}[/tex]

Now we solve for m, the mass, by isolating the variable.

m is being divided by 8.92 cubic centimeters. The inverse of division is multiplication, so we multiply both sides by 8.92 cubic centimeters.

[tex]8.92 \ cm^3 * 2.72 \ g/cm^3=\frac{m}{8.92 \ cm^3}* 8.92 \ cm^2[/tex]

[tex]8.92 \ cm^3 * 2.72 \ g/cm^3=m[/tex]

The units of cubic centimeters cancel out.

[tex]24.2624 \ g =m[/tex]

The mass of this piece of limestone is 24.2624 grams.

Answer:

40

Explanation:

M = n/v  hope this helps :b

Answer:

Acids: Tastes Sour

Has a ph less than 7

Base: Bitter

Has a ph greater than 7

slippery

Acid&Base: Conducts electricity

Answer:

1. Vapor pressure of dry oxygen gas = 747.68 torr

2. Volume at STP = 39.97 mL

3. Number of oxygen gas molecules = 1.074 × 10²¹ molecules

4. Percent purity of KClO3 = 97.3 %

Explanation:

The balanced equation for the reaction is given below :

2 KClO3 (s) ------> 2 KCl (s) + 3 O2 (g)

1) Since the water level in the eudiometer was below the outside water level in the beaker,

Vapor pressure of dry oxygen gas = Total pressure + pressure due to difference in water levels - vapor pressure of water

Vapor pressure of water at 20 °C is 17.535 mm (torr).

Pressure due to difference in water level = 4.22 cm × 10mm/cm / 13.534 (13.534 is the density of mercury) = 3.118 mm (torr).

Vapor pressure of dry oxygen gas = 762.10 torr + 3.118 torr - 17.535 torr

Vapor pressure of dry oxygen gas = 747.68 torr

2) P₁ = 747.68 torr; V₁ = 43.60 ml; T1 = 20 °C + 273.15 = 293.15 K

P₂ = 760 torr; T₂ = 273.15 K; V₂ = ?

Using the general gas equation = P₁V₁/T₁ = P₂V₂/T₂

V2₂= P₁V₁T₂ / P₂T₁

V₂ = (747.68 × 43.60 × 273.15 ) / (760 × 293.15)

V₂ = 39.97 ml

Volume of dry oxygen gas at STP = 39.97 mL

3) Volume of oxygen gas at STP 39.97 mL = 0.03997 L

Number of moles of oxygen gas in 0.03997 L = volume of gas at STP /molarvolume at STP

Number of moles of oxygen gas = 0.03997/22.4 L

Number of molecules of oxygen gas = 0.03997/22.4 L × 6.03 × 10²³ molecules

Number of oxygen gas molecules = 1.074 × 10²¹ molecules

e) Number of moles of oxygen gas = 0.03997/22.4 = 0.001784 moles

From the equation, mole ratio of oxygen gas and potassium chlorate is 3 : 2

Moles KClO3 = 2/3 × 0.001784 moles = 0.001189 moles

Molar mass of KClO3 = 39 + 35.5 + 3 × 16 = 122.5 g

Actual mass of KClO3 decomposed = 122.5 grams × 0.001189 mole = 0.146 grams

Percent purity = (actual mass KClO3 decomposed / sample mass of impure KClO3) × 100%

Percent purity = (0.146/0.150) × 100% = 97.3 %

Answer:

Solute is Pottasium Nitrate and Solvent is Water.

Explanation:

Answer:The lungs expel the carbon dioxide and bring in new oxygen-containing air. Only when both systems are working together can oxygen and carbon dioxide be successfully exchanged between cells and environment. There are many other examples of this cooperation in your body.

Explanation:

Hope it will help

Question:

A body system is a group of organs that work together to keep the organism

alive. How does the respiratory system help to keep an organism alive?

A. The respiratory system helps the organism respond to its

environment.

B. The respiratory system helps the organism absorb nutrients from

its environment.

O C. The respiratory system takes in oxygen and releases carbon

dioxide.

O D. The respiratory system carries oxygen to the organism's cells.​

Answer:

O C. The respiratory system takes in oxygen and releases carbon

dioxide.

Explanation:

Breathing uses chemical and mechanical processes to bring oxygen to every cell of the body and to get rid of carbon dioxide. Our body needs oxygen to obtain energy to fuel all our living processes. Carbon dioxide is a waste product of that process

Hope This Helps?

Answer:

b or c but I would just pick c

Answer:

C

Explanation:

Sun is an energy source not a matter.

Answer:

7.76 x 10^-3 M

Explanation:

pH = -log(x)

2.11 = -log (x)

10^-2.11 = 7.76x10^-3 M

Considering the definition of pH, the concentration [H⁺] is  7.76×10⁻³ M

You need to know that pH is the Hydrogen Potential. It is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.

Mathematically, pH is calculated as the negative base 10 logarithm of the activity of hydrogen ions:

pH= - log [H⁺]

The numerical scale that measures the pH of substances includes the numbers from 0 to 14. The pH value 7 corresponds to neutral substances. Acidic substances are those with a pH lower than 7, while basic substances have a pH higher than 7.

In this case, being pH= 2.11, you can replace this value in the definition of pH:

2.11= -log [H⁺]

Solving:

[H⁺]= 10⁻² ¹¹ M

[H⁺]= 7.76×10⁻³ M

Finally, the concentration [H⁺] is  7.76×10⁻³ M

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Answer:

O Nitrogen must be converted into a useful form by bacteria.

This bacteria is called the nitrogen fixing bacteria such as the Rhizobium bacteria.

Answer:

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Explanation:

vugjb oh in luv ug ug yf fyi dxezw f f g gjhc ydzt

Answer:

Ni(NO₃)₂ + Na₂CO₃ ⇒ NiCO₃ + 2 NaNO₃

Explanation:

Let's consider the unbalanced equation for the reaction that occurs when aqueous solutions of nickel(II) nitrate and sodium carbonate are combined. This is a double-replacement precipitation reaction.

Ni(NO₃)₂ + Na₂CO₃ ⇒ NiCO₃ + NaNO₃

We will balance the equation using the trial and error method.

First, we will balance Na atoms by multiplying NaNO₃ by 2.

Ni(NO₃)₂ + Na₂CO₃ ⇒ NiCO₃ + 2 NaNO₃

As we can see, the equation is balanced.

Answer:

Option B, 2.167 x 1024 atoms

Explanation:

1 mole of CO2 = 44.01 grams

Number of moles of CO2 in 158.4 gram sample

[tex]\frac{158.4}{44.01} \\3.95[/tex]moles

Number of atoms in one mole is [tex]6.02*10^{23}[/tex]

Number of atoms in 3.95 moles [tex]2.167 *10^{24}[/tex]

Hence, option B is correct

Explanation:

NiCl2 + KOH = NiOH + KCl

since nickel is the primary element in nickel ii chloride, find the oxidation no of nickel in the compound and chlorine should have 2 as a subscription since the ii in the compound represents that nickel has an oxidation no of 2

Answer:

Each chromosome contains many copies of the same gene

Answer:

Offspring receive a mix of genes from two different parents

Good luck!

Answer:

Find the mass of 1 mole.

mass of

1

mole of

131.39

g

m

o

l

C

2

H

C

I

⋅

3

=

37.04000067

g

Explanation:

hope it helps make brainlliest ty

Answer:subscript

Explanation:

Answer:

0.703g Na must reacted

Explanation:

The reaction of Sodium, Na, With water, H₂O is:

2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)

Where 2 moles of sodium reacts with an excess of water to produce 1 mole of hydrogen

To solve this question we have to use PV = nTR to solve the moles of the gas. With the moles of hydrogen we can find the moles of sodium that reacted and its mass:

Moles H₂:

PV = nRT

PV /RT = n

Where P is pressure = 1.15atm

V is volume in liters = 0.325L

R is gas constant = 0.082atmL/molK

T is absolute temperature = 25°C + 273 = 298.0K

1.15atm*0.325L / 0.082atmL/molK*298.0K = n

0.0153 moles of hydrogen are produced

Moles Na:

0.0153 moles H₂ * (2moles Na / 1mol H₂) = 0.0306 moles Na

Mass Na -Molar mass: 22.99g/mol-:

0.0306 moles Na * (22.99g / mol) =

Answer:

Polymerization, any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer. The monomer molecules may be all alike, or they may represent two, three, or more different compounds.

Answer:

There are 20 electrons.

Explanation:

Chlorine has 17 electrons in its atom to begin with (you can tell from the proton number in the periodic table).

A charge of -3 means that the chlorine atom gained 3 electrons, and now needs to lose 3 electrons to return to its atom configuration.

Answer:

There are approximately 366.25 sidereal days in a year so that the Earth spins 366.25 times with respect to distant stars in a year

hope this helps

have a good day :)

Explanation:

Answer:

5 half lives

Explanation:

Given that

Thorium - 236 contains the half-life of 10.0 minutes

And there is 250 grams

We need to find out the number of half lives that took place after 50.0 minutes

As in the question

1 half life is 10 minutes

So for 50 minutes, it would be

= 50 minutes ×  1 half life ÷ 10 minutes

= 5 half lives

Answer:

I'll explain.

Explanation:

The molecules of two different elements, nitrogen and oxygen, make up about 99 percent of the air. The rest includes small amounts of argon and carbon dioxide. Oxygen is the life-giving element in the air. You can tell because they're on the periodic table which is a table for elements.

Explanation:

nitrogen and oxygen are the gases in the air which are elements you can simply say it by looking the periodic table

Answer:

the desert (33% of the worlds surface)

Explanation:

Most of the world's surface is covered in water, in the form of oceans. The remaining landmass of Earth amounts to approximately 29 per cent of the surface. Of this remaining 29 per cent, deserts of all types constitute an estimated 33 per cent, or one-third, of the Earth's total landmass.

In simplest terms, water makes up about 71% of the Earth's surface, while the other 29% consists of continents and islands.

Only about 7.5% of the Earth's surface provides the agricultural soil on which we depend for the world's food supply and this fragment competes, sometimes unsuccessfully, with all other needs: housing, cities, schools, hospitals, shopping centres, landfills, etc.

Learn more about the percentage of water to land on Earth here:  https://brainly.com/question/21459960

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Nitrous oxide decomposes into nitrogen and oxygen, according to 2 N2O (g) -> 2 N2 (g) + O2 (g). ... In an experiment, a stream of N2O is passed through a tube 25 mm in diameter and 20 cm long. The flow rate of the gas is 0.75 L/min.

Answer:

As the oxygen is only transferred from the copper oxide to form water inside the apparatus, any gain in mass is due to hydrogen combined with the oxygen to form water. The ratio of the two masses enables the mass of oxygen combining with 1 g of hydrogen to be calculated.

Hydrogen and oxygen are the elements used as fuels in rockets as they are propellants. In each of the tests, the ratio of the mass of hydrogen to oxygen is 1:8.

Combustion has been the chemical reaction that involves reactants combining and reacting with oxygen resulting in heat and light formation. They are majorly used in propelling engines and in rocket fuels.

In a rocket engine oxygen acts as the oxidizer that reacts with hydrogen atoms to derive the heat and energy so that the engine can move and produce thrust. It uses Newton's third law to create energy and accelerate upwards.

The mixtures of fuel contain various masses that are present in a ratio of 1:8 (hydrogen: oxygen) as masses of hydrogen are 1, 2, and 5 mg, whereas oxygen is 8, 16, and 40 mg. It can be concluded that 1 part of hydrogen reacts with 8 parts of oxygen in the rocket fuel mixture.

Therefore, the rocket fuel mixtures contain a 1:8 ratio of the masses of hydrogen: oxygen that undergoes combustion reaction.

Learn more about combustion, here:

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Answer:

I think it is a rock...

Explanation:

maybe idrk tho