Which of the following is a physical change?

a. burning gasoline

b. cooking an egg

c. decomposing meat

d. evaporating water

Answer:

19

Explanation:

The mass of an atom is given by its mass number. This is because the mass of an atom is concentrated at the nucleus.

Mass number = number of protons + number of neutrons

Protons and neutrons are the most massive particles in any atom.

Protons are the positively charged particles in an atom

Neutrons are uncharged particles.

  So, the mass number of this atom is:

      Mass number  = 9 + 10 = 19

Answer:

troposphere

stratosphere

exosphere

Answer:

Molecular formula = C₄H₁₂O₂

Explanation:

Given data:

Percentage of hydrogen = 13.80%

Percentage of carbon = 51.02%

Percentage of oxygen = 35.18%

Molecular formula = ?

Solution:

Number of gram atoms of H = 13.80 / 1.01 = 13.6

Number of gram atoms of O = 35.18 / 16 = 2.2

Number of gram atoms of C = 51.02 / 12 = 4.25

Atomic ratio:

            C                      :      H             :         O

           4.25/2.2           :     13.6/2.2     :       2.2/2.2

            2                      :        6          :        1

C : H : O = 2 : 6 : 1

Empirical formula is C₂H₆O.

Molecular formula:

Molecular formula = n (empirical formula)

n = molar mass of compound / empirical formula mass

Empirical formula mass = C₂H₆O = 46 g/mol

n = 88 / 46

n = 2

Molecular formula = n (empirical formula)

Molecular formula = 2 (C₂H₆O)

Molecular formula = C₄H₁₂O₂

Answer:

Advantage and disadvantage of asexual reproduction in plant is described below in details.

Explanation:

An advantage of asexual reproduction is that the resulting plant will approach adulthood quicker. Since the new plant is emerging from a grown-up plant or plant components, it will also be stronger than a seed. Asexual reproduction can take a spot by natural or manufactured (assisted by humans) means.

The significant disadvantages of asexual reproduction are the Shortage of diversity. Following the seeds are genetically the same as the parent they are more sensitive to the same diseases and nutrient insufficiencies as the parent. All the negative deviations endure for generations.

Answer: energy is transferred, but it can go to the products or the reactants.

Explanation: in a chemical reaction, the atoms and molecules that interact with each other are called reactants.

Answer:

1

Explanation:

Answer:

divide all coefficients by 2.

Explanation:

Answer: D

Explanation:

Answer: One formula unit of NaCl consists of one cation, whose chemical symbol is [tex]Na^+[/tex] and one anion whose chemical symbol is [tex]Cl^-[/tex]

Explanation:

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.  

The cation is formed by the metal sodium which forms  [tex]Na^+[/tex] and the anion is formed by non metal chlorine which forms [tex]Cl^-[/tex].

For a formula unit of sodium chloride,  the charges have to be balanced , thus the valencies of ions are exchanged and the neutral compound result. Thus

[tex]Na^+[/tex] and  [tex]Cl^-[/tex] combine to form neutral [tex]NaCl[/tex]

Answer:

rest until and unless an external force is applied.

Answer:

Explanation:

Polar bonds also often contribute to a net dipole moment of a molecule. This basically means that there are partial charges that make a molecule overall polar. One example might be water: in H20, oxygen is very electronegative, and hydrogen is less so. This means that oxygen is more negative and hydrogen is more positive. This is why water is cohesive (can stick together): The positive ends stick to the negative ends.

To solve this we must be knowing each and every concept related to polar molecule.  Therefore, polar and nonpolar molecules are covalent compound.

A polar molecule is a type of chemical compound where there is an uneven distribution of electrons among the covalently bound atoms.

The term "polarity" refers to how unlike two molecules' electrical poles are from one another. If they are quite dissimilar, the species is said to be an extremely polar molecule.

Because of the more symmetrical distribution of the electrons, non-polar molecules do not have a lot of charges on their opposing sides. The fees are all offset by one another. Polar and nonpolar molecules are covalent compound.

Therefore, polar and nonpolar molecules are covalent compound.

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Answer:

Explanation:

The new volume can be found by using the formula for Boyle's law which is

[tex]P_1V_1 = P_2V_2[/tex]

From the question we have

[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]

From the question we have

[tex]V_2 = \frac{40 \times 20}{80} = \frac{800}{80} = 10 \\ [/tex]

We have the final answer as

hope this helps you

Answer:

K I will attempt

Explanation:

a)

[tex]O_2_{(g)}+ 2H_2_{(g)} => 2H_2O_{(l)}\\[/tex]

b)

1 : 2 : 2 (I don't know if this is what the question wants but it is what I would answer)

c)

Hydrogen because it requires 2 moles of H2 to react with 1 mole of O2

d)

24 moles of water. Look at stoichiometric coefficient. 2:2 means 24 moles you get 24 moles

e)

Oxygen. 2 < 5/2. Remember, 1 mole of O2 requires 2 moles of H2. But 5/2 is still greater than 2

f)

First, let's find out how many moles of water we can get. Since O2 is the limiting reactant, and O2:H2O ratio is 1:2, we will get 4 moles of H2O. Then, we can multiply 4 by Avogadro's number which is [tex]6.022*10^{23}[/tex] to get the number of molecules. We get: 2.41 * 10^24 molecules of water.

Answer:

I'ma just take the point thank you very much

Answer:

0.00001= 1 x 10^-5. Since HCl is an acid, 1 x10^-5 is the H+ concentration. Write only the number of the exponent. Therefore, pH = 5.

Answer:

40.32L

Explanation:

So we know that 22.4 Liters is one mole of a gass so we can set up an equation to test that

1mole     1.8mole

_____ = _____

22.4L         x

and then cross multiply so you get 40.32L

Answer:

40.32L

Explanation:

Just did worksheet

Answer:

[tex]T_1 = -57.15^{\circ}C[/tex]

Explanation:

Given

[tex]P_1 = 650mmHg[/tex] --- Initial Pressure

[tex]V_1 = 5.0L[/tex] --- Initial Volume

[tex]V_2 = 5.7L[/tex] --- Final Volume

[tex]P_2 = 800mmHg[/tex] --- Final Pressure

[tex]T_2 = 30C[/tex] ---- Final Temperature

Required

Determine the initial temperature (T1)

This question will be solved using combined gas law which states:

[tex]\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}[/tex]

However, the final temperature must be converted to degree kelvin

[tex]T_2 = 30C[/tex] --- Add 273.15

[tex]T_2 = 30k + 273.15 k[/tex]

[tex]T_2 = 303.15k[/tex]

Make T1 the subject in [tex]\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}[/tex]

[tex]T_1 = \frac{P_1V_1T_2}{P_2V_2}[/tex]

Substitute values for P1, V1, T2, P2 and V2

[tex]T_1 = \frac{650 * 5.0 * 303.15}{800 * 5.7}[/tex]

[tex]T_1 = \frac{985237.5}{4560}[/tex]

[tex]T_1 = 216.060855263[/tex]

Approximate

[tex]T_1 = 216k[/tex]

Convert to degree Celsius

[tex]T_1 = 216k[/tex] --- Subtract 273.15

[tex]T_1 = 216 - 273.15[/tex]

[tex]T_1 = -57.15^{\circ}C[/tex]

Hence, the initial temperature is -57.15C

Answer:

Magma becomes rock after the heating process has settled.

Explanation:

Magma is a kind of lava or in other words "Hot melted rock". When rock get really hot it transforms from rock it's solidified state and becomes magma. When magma is hot it can stay that way for a while or until it cools down. When magma does cool down it starts the solidifying state start to come out. If you let the magma cool it will become rock again. This process will happen over and over and it never stops. Every time magma gets cool it hardens, every time it gets hot it melts or and becomes magma. So in conclusion magma only turns back when it has been heated up and liquify.

The rock cycle explains the formation and breaking of the three forms of the rocks through various modes. The magma becomes rocks and magma again through the heating and cooling process.

Magma has been the semi-hot liquid that is present in the mantle in the lithosphere of the earth. They have very high temperatures and can push through the crust in the form of volcanic eruptions.

The magma changes its form from semi-liquid to rocks and back to magma again through the rock cycle. The hot molten magma pushes through the crust, cools, and then forms rocks. These rocks after many years start melting at higher temperature or get deep down the mantle where it converts to semi-liquid again.

Therefore, the rock cycle converts the magma.

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Answer:

Similarity: Rocks within the mantle contain more magnesium and iron than the ones in the crust.

Difference: Rocks in the deep mantle are under intense heat and pressure. In this case, they are semi-solid rocks that flow slowly. On the other hand, the part of the mantle that is nearest to the surface consists of rigid rocks. It has a lower temperature than the rocks in the deep mantle.

Explanation:

Rocks within the mantle contain more magnesium and iron than the ones in the crust.

Rocks in the deep mantle are under intense heat and pressure. In this case, they are semi-solid rocks that flow slowly.

On the other hand, the part of the mantle that is nearest to the surface consists of rigid rocks. It has a lower temperature than the rocks in the deep mantle.

According to geologists, a rock is a naturally occurring material made up of crystalline crystals of various minerals that have fused together to form a solid mass.

Therefore, Rocks within the mantle contain more magnesium and iron than the ones in the crust.

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Answer:

An ion is an atom or molecule that has a different number of electrons than protons, so it has a charge.

Explanation:

Trust me please

Answer:

A)

Explanation:

Entre todos esas materias el hidrógeno es el más fuerte

Answer:

0.045 moles

Explanation:

Given data:

Moles of CO = ?

Volume of gas = 1 L

Temperature and pressure = standard

Solution:

The given problem will be solve by using general gas equation,

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

n = PV/RT

n = 1 atm× 1L / 0.0821 atm.L/mol.K × 273 K

n = 1 atm.L / 22.41 atm.L/mol

n = 0.045 mol

Answer:

ye

Explanation:

ye

Answer: not to be rude but who is Miley partridge? If she is a friend then u r a kind hearted person

Explanation:

Answer: aluminium, mercury , platinum and copper.

Explanation:

A single replacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution. Thus one element should be different from another element.

A general single displacement reaction can be represented as :

[tex]XY+Z\rightarrow XZ+Y[/tex]

Thus the metals which are more reactive than magnesium will react with magnesium sulphate solution.

The metals which are more reactive than magnesium are aluminium, mercury , platinum and copper.

Answer:

I think Ne electron configuration

Answer:

D 2-7-2

Explanation:

I got it wrong and then they showed me the right answer

Answer:

Conduction is the transfer of thermal energy through direct contact. Convection is the transfer of thermal energy through the movement of a liquid or gas. Radiation is the transfer of thermal energy through thermal emission.

ill guess c

Explanation:

g

God is GOOD AND arr you sure that is written properly

Answer:

The students should create a project in which they each look at a unique trait that each have (for example, detached ear lobes) and look at their parents to see if they too have this trait. To take it a step further, look at their grandparents for this trait, and ask them about their parents and if they have this trait, this could tell them whether the trait has always, been apparent within the family, if it skipped a generation, or the genetics of one parents were more dominant then the other.