7th grade science lol help​

Answer:

False

Explanation:

A liquid has a definite shape and takes on the volume of its container. A gas has both the shape and the volume of its container. The particles in a gas cannot be compressed into a smaller volume. Liquids tend to contract when heated.

Hope this helps

Answer:

Scientists know that today the Earth's magnetic field is powered by the solidification of the planet's liquid iron core. The cooling and crystallization of the core stirs up the surrounding liquid iron, creating powerful electric currents that generate a magnetic field stretching far out into space.

Given :

It takes 45.60 mL of a 0.225 M hydrochloric acid solution to react completely with 25.00 mL of calcium hydroxide in the given reaction.

2HCl(aq) + Ca(OH)2(aq) --> CaCl2(aq) + 2H2O(l)

To Find :

The molar concentration of the calcium hydroxide solution.

Solution :

From given equation 2 mole of hydrochloric acid react with 1 mole of calcium hydroxide.

So,

[tex]2M_1V_1 = M_2V_2\\\\2\times 0.225 \times 45.60 = M_2 \times 25 \\\\M_2 = \dfrac{20.52}{25}\\\\M_2 = 0.8208 \ M[/tex]

Therefore, molar concentration of the calcium hydroxide solution is 0.8208 M.

Answer:

Molar concentration of the calcium hydroxide solution = 0.2052 M

Explanation:

Volume of HCl = 45.60 mL  = 0.0456 L

Molar concentration of HCl = 0.225 M

Volume of Ca(OH)2 = 25.00 mL  = 0.025 L

No. of moles of HCl = (0.225 M)*(0.0456 L)   = 0.01026 mol

As we know

2 moles of HCl require 1 mole of Ca(OH)2, hence, .01026 moles of HCl will need 0.5*(0.01026) = 0.00513 moles of Ca(OH)2

Molar concentration of Ca(OH)2 = [(0.00513 mol)/(0.025 L)]   = 0.2052 M

Answer: true

Explanation:

Answer:

reactivity

Explanation:

for example atoms in group 7 react by gaining 1 electron to become stable but they do not have the same number of energy levels

Answer:

221.22K or -51°C

Explanation:

We will be using the Ideal Gas Law to calculate the temperature of the gas. It is a mathematical relationship that describes the behavior of ideal gas ample for any combo of varying pressure, volume, temperature, and # of moles (n). It is derived by combing Boyle's Law, Charles' Law, Gay-Lussac's & Avogadro's Law.

Note: As always, remember that temperature must be in Kelvin not Celsius when using this equation.

Ideal Gas Law: [tex]PV = nRT[/tex], where P = pressure, V = volume (in Liters), n = # of moles, R = the ideal gas constant, and T = temperature (in Kelvin).

Based on the problem, we are given the pressure, volume, and # of moles. We are asked to find the temperature. What about R you ask? Well, R is a constant that is the value of 1 mole of gas at STP. R has various values depending on the pressure units. In this case, our pressure is in atm so the R value = 0.0821.

Onto the math - all that needs to be done now is to plug and chug. Plug in the given values to find the temperature:

Set up: [tex](7.6 atm)(12L) = (5 mol)(0.0821 L*atm/(mol*K))(T)[/tex]

==> [tex]T = \frac{(7.6 atm)(12L)}{(5 mol)(0.0821 L*atm/(mol*K))}[/tex]

==> T = 221.17K

The answer is 221.17K. To convert into Celsius, subtract by 273.15 to get -50.99 or -51°C.

Answer:

A saturated solution is a mixture in which the maximum amount of a given solute has been dissolved into the solvent. ... At this point adding more solute will not change the concentration of the solution; adding more solute will simply result in more solid at the bottom of the solution.

Answer:

will not change

Explanation:

A saturated solution is a mixture in which the maximum amount of a given solute has been dissolved into the solvent. ... At this point adding more solute will not change the concentration of the solution; adding more solute will simply result in more solid at the bottom of the solution.

Explanation:

Na3PO4+ FeCl3 = 3NaCl + FePO4

Hope it will help :)❤

The net ionic equation is found to be balanced by both mass and charge. There are equal masses of each element on the product and reactant sides in a balanced net ionic equation.

A chemical equation which shows only those elements, compounds, and ions which are directly involved in the chemical reaction is defined as the net ionic equation. The net ionic equation give us information about the ions that exists in aqueous medium.

A net ionic equation does not consider the spectator ions. The ions which do not participate in chemical reactions and are seen on both sides of the reactions are called spectator ions.

The complete ionic equation for the given reaction is:

3Na⁺ (aq) + PO₄³⁻ (aq) + Fe³⁺ (aq) + 3Cl⁻ (aq) → 3Na⁺ (aq) + 3Cl⁻ (aq) + FePO₄ (s)

The net ionic equation is:

PO₄³⁻ (aq) + Fe³⁺ (aq) → FePO₄ (s)

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Answer:

[tex]Sn(CO_3)_2[/tex] and [tex]NaNO_3[/tex].

Explanation:

Hello there!

In this case, according to the described chemical reaction between sodium carbonate and tin nitrate, we can write the undergoing chemical reaction:

[tex]2Na_2CO_3+Sn(NO_3)_4\rightarrow Sn(CO_3)_2+4NaNO_3[/tex]

Thus, we notice that the products are strontium carbonate and sodium nitrate, whose formulas are [tex]Sn(CO_3)_2[/tex] and [tex]NaNO_3[/tex] respectively.

Best regards!

Answer: The percentage of potassium iodide in the sample is 2.63 %.

Explanation:

The chemical equation for the reaction of iodide ions with bromine gas follows:

[tex]I^-+3Br_2+3H_2O\rightarrow 6Br^-+IO_3^-+6H^+[/tex]                (i)

The chemical equation for the reaction of iodate ions with barium ions follows:

[tex]Ba^{2+}+2IO_3^-\rightarrow Ba(IO_3)_2[/tex]                 ......(ii)

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

Given mass of barium iodate = 0.0596 g

Molar mass of barium iodate = 487.13 g/mol

Using equation 1:

[tex]\text{Moles of barium iodate}=\frac{0.0596 g}{487.13 g/mol}\\\\\text{Moles of barium iodate}=1.22\times 10^{-4} moles[/tex]

By Stoichiometry of the reaction (ii):

1 mole of barium iodate is produced by 2 moles of iodate ions

So, [tex]1.22\times 10^{-4} moles[/tex] of barium iodate will be produced by [tex]\frac{2}{1}\times 1.22\times 10^{-4} =2.44\times 10^{-4}moles[/tex] of iodate ions

By the stoichiometry of the reaction (i):

1 mole of iodate ions are produced by 1 moles of iodine ions

So, [tex]2.44\times 10^{-4} moles[/tex] of iodate ions will be produced by [tex]\frac{1}{1}\times 2.44\times 10^{-4} =2.44\times 10^{-4}moles[/tex] of iodine ions

Moles of potassium iodide = Moles of iodide ions = [tex]2.44\times 10^{-4}[/tex]

Since, the molar mass of potassium iodide = 166 g/mol

Using equation 1:

[tex]\text{Mass of potassium iodide}=2.44\times 10^{-4}mol\times 166 g/mol\\\\\text{Mass of potassium iodide}=0.0405 g[/tex]

To calculate the percentage by mass of a substance, the equation used is:

[tex]\text{Percent by mass}=\frac{\text{Mass of a substance}}{\text{Mass of solution}}\times 100[/tex]

Mass of a solution = 1.54 g

Mass of potassium iodide = 0.0405 g

Using above equation:

[tex]\text{Percent potassium iodide}=\frac{0.0405 g}{1.54g}\times 100\\\\\text{Percent potassium iodide}=2.63\%[/tex]

Hence, the percentage of potassium iodide in the sample is 2.63 %.

Expressing the results of potassium iodide in percentage = 2.63%

The chemical reaction of iodine ions with Bromine gas can be expressed as :

I⁻  + 3Br₂  + 3H₂O  -- > 6Br⁻ + IO₃ + 6H⁺ ----- ( 1 )

Chemical reaction between iodate ions with barium ions  can be expressed as :  Ba²⁺  + 2IO⁻₃ ------> Ba ( IO₃ )₂   --------- ( 2 )

Step 1 : Calculate the number of Barium iodate moles

mass of Barium iodate = 0.0596 g

molar mass of Barium iodate = 487.13 g/mol

from equation ( 1 )

moles of Barium iodate = ( 0.0596 ) / ( 487.13 ) = 1.22 * 10⁻⁴ moles

also from equation ( 1 ) the moles of potassium iodide = moles of iodide ions

= 2.44 * 10⁻⁴

molar mass of potassium iodide = 166 g/mol

Next step : Determine the mass of potassium iodide

moles of potassium * molar mass

= 2.44 * 10⁻⁴  * 166 g/mol  = 0.0405 g

Final step : Determine the percentage of potassium iodide in the solution

Percentage = ( mass of potassium iodide / mass of solution ) * 100

                   = ( 0.0405 / 1.54 ) * 100

                   = 2.63%

Hence we can conclude that potassium iodide in percentage = 2.63%

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Answer:

The answers to your questions are given below.

Explanation:

__ NaBr + CaF₂ —> __ NaF + CaBr₂

The above equation can be balance as follow:

NaBr + CaF₂ —> NaF + CaBr₂

There are 2 atoms of F on the left side and 1 atom on the right side. It can be balance by writing 2 before NaF as shown below:

NaBr + CaF₂ —> 2NaF + CaBr₂

There are 2 atoms of Na on the right side and 1 atom on the left side. It can be balance by writing 2 before NaBr as shown below:

2NaBr + CaF₂ —> 2NaF + CaBr₂

Now, the equation is balanced.

Atom >>>> Reactant >>>> Product

Na >>>>>> 2 >>>>>>>>>>> 2

Br >>>>>>> 2 >>>>>>>>>>> 2

Ca >>>>>> 1 >>>>>>>>>>>> 1

F >>>>>>> 2 >>>>>>>>>>>> 2

Answers:

1. firstly Start numbering from that carbon atom which would be nearest to chlorine .

2. then if u observed properly , both chlorine is attached are attached to 2nd carbon atom.

3.but in first one chlorine is on the left side

whereas in the second one chlorine right side.

p.s:

1. well, were u have number carbon three in above pic take it as C1 than C2( if u observed it is were Cl is attached to C2 ) than C3 ,C4.

2. Then similarly in second molecules where u have number C3 in above pic take it as C1 than C2 (if u observed , again Cl is attached to C2 but this time it is one on opposite sides.

now imagine if u kept first molecules on second one.

matching C1 C2 C3 C4 of first molecules with

C1 C2 C3 C4 of second molecule .

u will observed that in both of them Cl is on C2 but they in exactly opposite position

Explanation:

Enantiomers are a pair of molecules that exist in two forms that are mirror images of one another but cannot be superimposed one upon the other.

Answer:

-1,300 kJ

I don't want to explain it brainly AAAAA

The standard enthalpy of the reaction is the enthalpy change which occurs in a system when a matter is transformed by a chemical reaction under standard conditions. Here the enthalpy of the overall chemical reaction is  -1,300 kJ. The correct option is B.

In any general chemical reaction, the reactants undergo chemical changes to form products. The change in enthalpy is represented as ΔrH and is termed as the reaction enthalpy. It can be calculated by subtracting the sum of enthalpies of all the reactants from that of the products.

ΔrH  = ∑ aiH products - ∑ bi H reactants

Here we should reverse the first reaction and also multiply its ΔH by (- 1):

P₄O₆(s) → P₄(s) + 3O₂(g), ΔH₁' = 1640.1 kJ.

The second reaction is also reversed and also multiply its ΔH by (- 1):

P₄(s) + 5O₂(g) → P₄O₁₀(s), ΔH₂' = - 2940.1 kJ.

If we add the two reactions after modification, we get:

P₄O₆(s) → P₄O₁₀(s).

Therefore,  ΔH = ΔH₁' + ΔH₂' = 1640.1 kJ + (- 2940.1 kJ) = - 1300 kJ.

Thus the correct option is B.

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Answer:

B the weight of the passengers

Answer:

Molecular formula => C₅H₅O₅

Explanation:

From the question given above, the following data were obtained:

Empirical formula = CHO

molar mass of compound = 145 g/mol

Molecular formula =?

The molecular formula of the compound can be obtained as follow:

Molecular formula = Empirical formula × n

Molecular formula = [CHO]ₙ

[CHO]ₙ = 145

[12 + 1 + 16]n = 145

29n = 145

Divide both side by 29

n = 145 / 29

n = 5

Molecular formula = [CHO]ₙ

Molecular formula = [CHO]₅

Molecular formula => C₅H₅O₅

Answer:

SEE EXPLANATION

Explanation:

We must first obtain the molar mass of CHCl3 as follows;

CHCl3 = ( 12.01 * 1 )+ (1.008 * 1 ) + ( 35.45 * 3 ) => 119.37 g/mol

Then we obtain the percentage by mass of each element

For Carbon =  ( atomic mass C / molar mass CHCl3 ) * 100

C  =  (12.01 / 119.37 ) * 100

C = ( 0.1006 * 100 )

C =  10.06 %

For Hydrogen :

H = ( atomic mass H / molar mass CHCl3 ) * 100

H = ( 1.008 / 119.37 ) * 100

H = 0.008444 * 100

H = 0.8444 %

For Chlorine :

Cl  ( molar mass Cl3 / molar mass CHCl3 ):

Cl =  ( 3 * 35.5 / 119.37 ) * 100

Cl =  ( 106.5 / 119.37 ) * 100

Cl = 0.8921 * 100

Cl = 89.92%

Answer:

The KE increases.

Explanation:

KE=1/2(mv²)

So, as the velocity increases, kinetic energy also increases.

Answer:

238000 N

Explanation:

Use F=ma

Mass= 17000 kg

Accel.= 14 m/s²

Answer:

True

Explanation:

I learned about it a few years ago

Answer:

It's too far away

Explanation:

According to classical mechanics, gravitational pull is inversely proportional to the distance squared; as the distance increases, the gravitational pull decreases at a faster and faster rate. Since Alpha Centauri A is a few lightyears (Tens of trillions of kilometers away), without even needing to calculate the force of gravity, it is very miniscule.

Answer:

9.24

Explanation:

-logofH

Answer:

The value of n is 6

Explanation:

The half-reactions of the problem are:

Cr(s) → Cr³⁺ + 3e⁻

Pb²⁺ + 2e⁻→ Pb(s)

To balance the electrons we must multiply the half-reactions as follows:

2 * (Cr(s) → Cr³⁺ + 3e⁻)

3 * (Pb²⁺ + 2e⁻→ Pb(s))

2Cr(s) → 2Cr³⁺ + 6e⁻

3Pb²⁺ + 6e⁻→ 3Pb(s)

In Nernst equation, the value of n are the electrons used to balance the reaction, as in this problem, the electrons are 6:

Answer:

4 M

Explanation:

To answer this problem we can use the following formula:

Where the subscript 1 refers to the volume and concentration before diluting, and 2 refers to volume and concentration after diluting.

Meaning that in this case we can write:

We can now solve for C₁:

Answer:

The sky looks different in each nighttime section of the artifact because the artifact sections represent different seasons. ... Different constellations are visible on different nights throughout the year because of the earth's orbit. The Earth orbits around the sun. A full orbit is 365 days or one year.

Explanation:

Answer:

D. Mutation

Explanation:

Mutation is any change or alteration that occurs to the nucleotide sequence of a gene induced during DNA replication or by mutation-causing substances called MUTAGENS.

Mutation can be in the form of addition, removal, or substitution of nitrogenous bases in a DNA molecule. For example, in an original DNA sequence as follows: GAT ATC TGA, the following mutation can occur:

Addition: GAT ATC CTG A

Removal: GAT ATT GA

Substitution: GAT CTC TGA

Answer:

A. mushroom

Explanation:

Answer:

0.01804 M KMnO4 Solution.

Explanation:

3 Percent(w/w) H2O2 Are Sold In Drug Stores As A Disinfectant. ... H2O2 In A Bottle Of Peroxide Solution Was Done By Diluting 1.50 ML To 100 ML With Water, Acidifying With Dilute H2SO4 And Titrating With A 0.01804 M KMnO4 Solution.

Answer:

Explanation:

b

The rate of the reaction determines the product formation and depends on various factors. The increase in pressure will change the concentration of reactants. Thus, option B is correct.

The rate of the reaction is the speed at which the chemical reaction moves in a direction to yield products. The reaction rate is influenced by the surface area of the substance, temperature, and concentration.

The pressure directly affects the concentration which in turn affects the reaction rate. The increased pressure raises the concentration and more collisions will occur between the particles resulting in a fast rate of reaction.

Therefore, the increase in pressure increases the concentration and reaction rate.

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