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1 mark question

Answer:

Artificial selection, also called "selective breeding” is where humans select for desirable traits in agricultural products or animals, rather than leaving the species.

Answer:

Explanation:

Endo and Exo thermic are defined by what changes take place in the environment of the reaction.

If the temperature goes up, the reaction is giving up heat. It is Exothermic.

If the temperature goes down, the reaction requires heat. It is Endothermic.

In this case, the temperature went down. The reaction is Endothermic.

Answer:

Volume occupied is approx.  

38 ⋅ ML

Explanation:

Density  ρ = Mass  Volume  And thus  Volume  = Mass  ρ = 1.592 ⋅ l b × 454 ⋅ g ⋅ l b − 1 19.3 ⋅ g ⋅ m L − 1   =   ? ? ⋅ m L

Answer:

Magnesium is Mg.

Phosphorus is P.

Answer:

vigorous

Explanation:

As you go down group one of the periodic table, the reactions become and more vigorous.

Answer:

I think the answer is A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Physical properties include color, density, hardness, and melting and boiling points. A chemical property describes the ability of a substance to undergo a specific chemical change.

Explanation:

I hope this helps.

Answer:

Physical change is the same substance, while a chemical change is a new substance.

Answer:

A horizontal row in the periodic table, which signifies the totoal number of electron shells in an element's atom.

Explanation:

Hope this helpss)):

The periodic table is composed of metals and nonmetals arranged in groups and periods.

The periodic table is an arrangement of elements in groups and periods based on their properties. The properties of elements repeat at regular intervals hence the term, "periodic".

The answers to the questions are;

7)  Element Families on the Periodic Table have similar properties. There are 18 families.

8) Alkali Metals are good conductors of heat and electricity.

9) There are a total of 38 elements that are grouped as Transition Metals.

10)  As opposed to metals, non-metals can be very opaque. They have no metallic luster and do not reflect light.

11)  All Lanthanide Series elements occur naturally except for promethium.

12)  All Actinide Series elements are radioactive and most are synthetic.

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Answer:

    2H2    +   1 O2   ------>    2H2O

m = 12.7g                              m = ?

Get the number of moles for Hydrogen gas (H2) by dividing the mass by the molar mass (1.01g/mol as listed in the periodic table for its atomic mass)

12.7/1.01 = 12.57 mol of H2

Now use the mole to mole ratio of Hydrogen gas (H2) and water (H2O).

From the balanced equation, we can see that 2 mol of H2 gives us 2 mol of H2O. Since both of the ratios are equal (2:2), the moles we have for hydrogen gas is the same as the moles we get for water.

12.57 mol of H2O

Now that we have the amount of mol for H2O produced in this reaction, we can convert it to grams by multiplying the moles by the molar mass.

Molar mass of H2O = (1.01 x 2) + (16) = 18.02g/mol

12.57 x 18.02 = 226.5g (rounded)

Therefore 226.5g of water will be produced in this reaction

According to law of conservation of mass and stoichiometry, 114.3 g of water are produced if 12.7 grams of hydrogen reacted with an unknown amount of oxygen.

According to law of conservation of mass, it is evident that mass is neither created nor destroyed rather it is restored at the end of a chemical reaction .

Law of conservation of mass and energy are related as mass and energy are directly proportional which is indicated by the equation E=mc².Concept of conservation of mass is widely used in field of chemistry, fluid dynamics.

2 H₂ + O₂[tex]\rightarrow[/tex] 2 H₂O,according to this equation,4 g hydrogen reacts with 32 g oxygen to give 36 g water, thus 12.7 g of hydrogen will produce 12.7×36/4=114.3 g water and hence for this amount of water to be formed  12.7 g of hydrogen reacts with 101.6 g of oxygen which is obtained as 114.3-12.7=101.6 g

Thus, 114.3 g of water is produced.

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Answer: photosphere.

Explanation:

The part of the Sun commonly called its surface is the photosphere. The word photosphere means "light sphere" – which is apt because this is the layer that emits the most visible light. It’s what we see from Earth with our eyes.

To solve such this we must know the concept of acid and base reaction. Therefore, the concentration of acid decides the concentration of hydrogen gas evolved.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

When creating mixture the amount of hydrogen gas is directly related to the concentration of the acid mixture, the higher the concentration level The more hydrogen gas would be produced.

Therefore, the concentration of acid decides the concentration of hydrogen gas evolved.

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Answer:

D.

Explanation:

A concentrated solution is one that has a lot of solute (the substance being dissolved) in the solvent (the substance doing the dissolving). When a solution is concentrated, it means it has a high ratio of solute to solvent, so the answer is D.

Hope this helps.

Answer:

5. 0.02 seconds

6. (a) 0.0167 seconds

(b) Period in Lebanon is 0.02 seconds and in the U.S 0.0167 seconds. That means that the U.S. has the faster period.

Explanation:

Answer:

SO2

Explanation:

that's my answer

Sana mKatolong

Answer: Global warming causes sea-level rise as oceans expand, and makes storm patterns more energetic. Consequently it will affect most of the world's coastlines through inundation and increased erosion.

Explanation:

The equilibrium constant of the reaction is 0.042.

The reaction equation is given as;

PCl5(g) ⇄ PCl3(g) + Cl2 (g)

Recall that this equation shows the decomposition of phosphorus pentachloride.

We have the following equilibrium concentrations;

[PCI5]= 0.0095 M

[PCI3] = 0.020

[CI2] = 0.020 M

The equilibrium constant, K is obtained from;

K =  [PCI3]  [CI2]/[PCI5]

K = [0.020]^2/[0.0095]

K = 0.042

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find the distance between

the following points:

a) AC0₂0) and B(5, 2)

Answer:

The strongest intermolecular force in sulfur dioxide is dipole-dipole forces.

Explanation:

The interparticle force in [tex]SO_{2}[/tex] (sulfur dioxide) is the dipole-dipole interaction.

Dipole-dipole interaction is a type of intermolecular force that occurs between polar molecules. Polar molecules have a permanent dipole moment, which means they have a partial positive charge on one end and a partial negative charge on the other end. This creates an electrostatic attraction between the partial charges of neighboring molecules. The stronger the dipole moment of a molecule, the stronger its dipole-dipole interaction will be with other polar molecules.

Dipole-dipole interactions are responsible for a variety of physical properties of substances, including their boiling and melting points. Substances with strong dipole-dipole interactions tend to have higher boiling and melting points than substances with weaker interactions. In addition, the strength of dipole-dipole interactions can affect solubility, as polar substances tend to dissolve better in other polar substances due to their ability to form dipole-dipole interactions.

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This question is providing the masses of carbon dioxide and oxygen gases at 10.0 atm as 66 g and 16 g respectively, and is asking for the partial pressure of the former which turns out to be 7.50 atm after doing the math.

Thus, we can start solving this problem with the Dalton's law approach, in order to make a relationship for the total pressure, partial pressure and mole fraction, which means we must first determine the mole fraction of carbon dioxide gas in the mixture as shown below:

[tex]x_{CO_2}=\frac{n_{CO_2}}{n_{CO_2}+n_{O_2}}[/tex]

Next, we calculate the moles of both gases by dividing the grams over the molar masses:

[tex]n_{CO_2}=\frac{66g}{44.01g/mol} =1.50mol\\\\n_{O_2}=\frac{16g}{32g/mol} =0.5mol[/tex]

Then, the mole fraction of carbon dioxide as the required one by plugging in the previously calculated moles:

[tex]x_{CO_2}=\frac{1.5}{1.5+0.5}=0.75[/tex]

Finally, we use the definition of the Dalton's law to calculate the partial pressure of carbon dioxide gas in the binary mixture:

[tex]P_{CO_2}=x_{CO_2}P\\\\P_{CO_2}=0.75*10.0atm\\\\P_{CO_2}=7.50 atm[/tex]

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Answer:

-1.76202

Explanation: Because the operation is subtraction, you would count the number of digits after the decimal point. Then you would perform the operation and round your answer to the SMALLER number of digits after the decimal point.

Answer:

Both

Explanation:

if you pull a mountain a part that would be great consequences and if a volcano breaks there will be fire .

Answer:

a subshell is a subdivision of electron shells that are separated by electron orbitals.

Explanation:

(subshells are labeled s,p,d, and f in an electron configuration)

Answer:

the force that you applied caused the notebook to move.the force applied on the notebook by the table causes it to stop moving. this is because after sometime the book uses up the force and later the force you applied is less than that of the force by the table.