middle school science help please

Answer:

Im pretty sure its hydrocarbon

Explanation:

Answer:

......................

nh42so4

Answer:C

Explanation:I took the test

Answer:

It is a south pole because the field lines enter the magnet at this end.

Explanation:

Answer:

2grams as per the question

Answer:

Oxygen is more electronegative than sulphur

Explanation:

Bond angle of a molecule is related to the electronegativity of the central atom. The more electronegative the central atom is, the greater the bond angle.

As electronegativity of the central atom increases, the magnitude of bond pair- bond pair repulsion increases leading to increase in bond angle.

Hence, oxygen, being more electronegative than sulphur asserts a greater bond pair- bond pair repulsion leading to a greater bond angle in water.

The following equilibrium will shift in the direction of the product:

Given

Reaction

4HCl + O₂ → 2H₂O + 2Cl₂

Cl₂  was removed

Required

Equilibrium changes

Solution

Reaction = - action

adding the products ⇒ Shifts in the direction of the reactants

reducing the products ⇒Shifts in the direction of the products

Cl₂ as a product, so if Cl₂ is taken or reduced, the reaction will try to maintain system equilibrium by moving to the right (product formation) ⇒ Shift in the direction of the product:

Answer: (a) [tex]\Delta S^{0}[/tex] = - 242.2J/K.mol

              (b) [tex]\Delta S^{0}[/tex] = 163.34J/K.mol

              (c) Yes

Explanation: Entropy is the measure of randomness or disorder of a system. Standard Entropy has the symbol [tex]S^{0}[/tex].

Mathematically, Entropy is defined as

[tex]\Delta S^{0}=\Sigma S^{0}(products)-\Sigma S^{0}(reagents)[/tex]

Each substance has its own entropy value.

(a) Combustion of Methane:

[tex]CH_{4}+2O_{2}[/tex] ⇒ [tex]CO_{2}+2H_{2}O[/tex]

Using standard entropy table, entropy will be:

[tex]\Sigma S^{0}(products)=214+2(69.91)[/tex] = 353.8

[tex]\Sigma S^{0}=186.264+2(205.138)[/tex] = 596.54

[tex]\Delta S^{0}=[/tex] 353.8 - 596.54

[tex]\Delta S^{0}=[/tex] - 242.2

Standard Entropy for combustion of methane is [tex]\Delta S^{0}=[/tex] - 242.2 J/K.mol.

(b) Hydrolysis of Water:

[tex]H_{2}O_{(l)}[/tex] ⇒ [tex]H_{2}_{(g)}+1/2O_{2}_{(g)}[/tex]

[tex]\Sigma S^{0}(products)=130.684+0.5(205.138)[/tex] = 233.253

[tex]\Sigma S^{0}(reagents)=69.91[/tex]

[tex]\Delta S^{0}=[/tex] 233.253 - 69.91

[tex]\Delta S^{0}=[/tex] +163.34

Standard Entropy for hydrolysis of water is [tex]\Delta S^{0}=[/tex] + 163.34 J/K.mol

(c) Yes, the results prove the general rule: Reactions Entropies are positive for net formation of gas and negative for net reduction of gas. This happens because, as entropy is the measure of disorder, the entropy for gases are greater than for liquids and solids. So, when there is formation of a gas, Entropy increases and when there isn't, entropy decreases.

Answer:

Giant covalent are characterized by having high melting and boiling points as well as being solid at room temperature. Hence, option C is correct.

A covalent bond shares one or more pairs of electrons between two atoms.

Giant covalent structure:

Polythene: long chains of atoms that are able to rotate along the bonding axis.

Graphite: layers of (hexagonal) carbon sheets; each individual sheet are rigid (allows no rotation.)

Silicon dioxide: three-dimensional (tetrahedral) network of carbon and oxygen atoms; the entire network is very rigid (allows no rotation.)

Diamond: three-dimensional (tetrahedral) network of carbon atoms and is very rigid.

Hence, giant covalent are characterized by having high melting and boiling points as well as being solid at room temperature.

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Answer:

Explanation:

Kelvin is preferred for solving problems related to Charles' Law because , it is the Absolute temperature scale.

To convert Celsius to  Kelvin scale, you add 273 to the temperature in the centigrade/Celsius scale.

Answer:

1

1

1

1

Explanation:

the equation is balancing

Answer:

1Mg + 1Cl2 = 1MgCl2

Explanation:

Hi! When balancing an equation, you want to make sure that there are equal amounts of each element on both sides. When looking at the equation that you provided in the question, look and count how many of each element are on each side. I can see that there is 1 Mg ion on the left and 1 Mg ion on the right. There are also 2 Cl ions on the left and 2 Cl ions on the right. Because they are already equal, the coefficients in front of each compound will be 1. If the amounts were different on each side, that is when you would need to add different coefficients.

Hope this helps! Let me know if you have any other questions about this!

Answer:

1s22s22p63s23p63d104s24p1.

Explanation:

Gallium, Ga has 31 protons and 31 electrons.

Answer:

Ar 3d10 4s2 4p1

Explanation:

hope this serves you well!!

Answer:

Lithium nitrate

Explanation:

Lithium nitrate is an inorganic compound with the formula LiNO3. It is the lithium salt of nitric acid (an alkali metal nitrate).

Answer:

i do believe it is C. Chemical energy in food is transformed into mechanical energy as our body rides a bicycle down the street. but if i am wrong plz don't come at me but i believe that is right

Explanation:

Answer:

i do believe it is C. Chemical energy in food is transformed into mechanical energy as our body rides a bicycle down the street. but if i am wrong plz don't come at me but i believe that is right

Explanation:

The concentration of iron used in the titration : 0.009 M

Given

Reaction

Cr₂O₇²⁻ + 6Fe²⁺ + 14H⁺ ⇒ 2Cr³⁺ + 6Fe³⁺ + 7H₂O

0.0093 mol/L potassium  dichromate

200 cm³ of dilute acid, 25cm³   was used in the titration.

Required

the concentration of iron

Solution

Titration formula

C₁V₁n₁=C₂V₂n₂⇒ From equation : n₁=6n₂(1=Cr₂O₇, 2=Fe)

titration average : 33+32.05+32.15+32.1 / 4 = 32.325 cm³(ml)

25 cm³ of iron solution used in titration :

[tex]\tt V_1=32.325~ml\\\\V_2=25~ml\\\\C_1=0.0093~M\\\\\\\\C_1.V_1.n_2=C_2.V_2.n_1\\\\0.0093\times 32.325\times 6=C_2\times 25\times 1\\\\C_2=0.07215~M[/tex]

Dilution(25 ml from 200 ml iron solution)

[tex]\tt C_2.V_2=C_1.V_1\\\\0.007215\times 25=C_1\times 200\\\\C_1=0.009~M[/tex]

Answer: acidic

Explanation:

Answer:

3.77 x 10^-13 M

Explanation:

Answer:

See explanation and images attached

Explanation:

We know that the cis isomer has more heat of hydrogenation since it is less stable than the trans isomer. Since the hydrogenation of both compounds yields the same product and the hydroboration/oxidation both give a primary alcohol, they are geometric isomers and Y is the trans isomer (Image 2).

For the compound C8H12, the compound in question must be 1,5- cyclooctadiene since two moles of the same aldehyde was obtained after ozonolysis and reaction with two equivalents of hydrogen gives cyclooctane (Image 1).

Answer: Since k2 corresponds to 64 hours, the time for the milk to sour at 40 C is 64 h / 9.38 = 6.8 hours.

Explanation:

At temperature T1, the Arrhenius Equation is:

k1 = Ae^(-Ea/RT1).

An equivalent equation can be written at T2:

k2 = Ae^(-Ea/RT2).

If these equations are divided, then A cancels:

k1/k2 = e^(-Ea/RT1)/e^(-Ea/RT2)

Taking the natural log:

ln(k1/k2) = (Ea/RT2)-(Ea/RT1);

or:

ln(k1/k2) = (Ea/R)(1/T2 - 1/T1)

We can infer from the question that the milk sours 3 times as fast at the higher temperature (let's call it T1), so we can arbitrarily call k2 = 1 and k1 = 3.

a) Substitute:

ln(3) =  (Ea/R)(1/276.15 K - 1/293.15 K).

We get Ea/R = 5231.6. Multiply this by whatever value of R you choose to get Ea in your favorite energy unit. Remember the sig figs.

b) Again, let's let the lower temperature = T2, since we have defined k2 = 1:

ln(k1) = (5231.6)(1/276.15 K - 1/313.15);

ln(k1) = 2.24, so k1 = 9.38.

Since k2 corresponds to 64 hours, the time for the milk to sour at 40 C is 64 h / 9.38 = 6.8 hours.

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\[/tex]

From the question we have

[tex]volume = \frac{368}{19.5} \\ = 18.871794..[/tex]

We have the final answer as

Hope this helps you

Answer:

mercury

Explanation:

Answer:

large cracks suddenly form

Explanation:

the tectonic plates begin to move causing cracks. I think

Geologic Tools. Geologists use a lot of tools to aid their studies. Some of the most common tools used are compasses, rock hammers, hand lenses, and field books.

hope this helped <3

Answer:

wsp

Explanation:

is there a question or no? im confused.

Answer:

ethane

Explanation:

Ethane is an organic chemical compound with chemical formula C ₂H ₆. At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petrochemical by-product of petroleum refining

The statement that describes a physical change is a sculptor casts a statue in molten bronze and allows it to harden. The correct option is C.

"A physical change is one that simply affects the physical nature of the substance." Usually, increasing the temperature or applying pressure, both, will cause a physical change. In other words, physical changes are reversible.

All the other options like rusting of iron bolts on a bridge is a chemical change when iron reacts with oxygen in the air, it gets rust.

Similarly, silver cups exposed to air react with air is a chemical change, and option d, silver off magnesium that creates light, is also a chemical change.

Thus, the correct option is C. A sculptor casts a statue in molten bronze and allows it to harden.

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Answer:

5.The limiting reactant is completely used up in the reaction

Explanation:

The limiting reactant is completely used up in the reaction is the correct answer because a limiting reactant is a reactant in chemical reaction that is completely consumed or used up in the chemical reaction. Limiting reactant when it is completely used up limits the amount of products that will be formed. The reaction will be halted or will stop when the limiting reactant is totally used up.

The statement that is right as regards a limiting reactants in a reaction is 5:.The limiting reactant is completely used up in the reaction.

Therefore, option 5, is correct.

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OTHER OPTIONS THAT COMPLETE THIS QUESTION ARE:

The limiting reactant has a lower mass than other reactants.

2.The limiting reactant dictates the amount of product.

3.The limiting reactant is always the same for a given reaction.

4.There will be an excess of other reactants at the end of the reaction.