PLEASE HELP!
this is due tomorrow and i really need help!!! this is for my final grade! thank you

Answer:

Bones aren't made of calcium metal. Bones are a collegun structure filled in with mostly calcium carbonate and some calcium phosphate

Answer:

Bones aren't made of calcium metal. Bones are a collegun structure filled in with mostly calcium carbonate and some calcium phosphate

Explanation:

I hope this helps

Answer:

Its the first one

Explanation:

4 mol is the highest of the Bunch and 4.0L is the lowest making the first answer the correct one

Answer:

Heat Energy needed (Q) = 68250 J

Energy lost (Q') = 10500 J

Explanation:

Applying,

Q = cm(t₂-t₁)............. Equation 1

Where Q = heat  energy needed, c = specific heat capacity of water, m = mass of water, t₁ = initial temperature, t₂ = final temperature.

From the question,

Given: m = 250 g = 0.25 kg, t₁ = 20.0°C, t₂ = 85.0°C

Constant: c = 4200 J/kg°C

Substitute these values into equation 1

Q = 0.25(4200)(85-20)

Q = 68250 J.

Similarly, heat lost

Q' = cm(t₁-t₂)................. Equation 2

Where Q = heat lost

Given: t₁ = 85°C, t₂ = 75°C

Substitute into equation 2

Q' = 4200(0.25)(85-75)

Q' = 10500 J

Answer: The pH of the solution is 13.

Explanation:

pOH is defined as the negative logarithm of hydroxide ion concentration present in the solution.

[tex]pOH=-\log [OH^-][/tex]

We are given:

Concentration of [tex]Ca(OH)_2=0.05mol/dm^3=0.5mol/L[/tex]          (Conversion factor: [tex]1L = 1dm^3[/tex] )

1 mole of calcium hydroxide produces 1 mole of calcium ions and 2 moles of hydroxide ions

Concentration of [tex]OH^-=(2\times 0.05)=0.1mol/L[/tex]

Putting values in above equation, we get:

[tex]pOH=-\log (0.1)\\\\pOH=1[/tex]

We know:

[tex]pH+pOH=14\\\\pH=14-1\\\\pH=13[/tex]

Hence, the pH of the solution is 13.

Answer:

ver explicacion

Explanation:

La investigación cualitativa tiene que ver con la investigación que implica la recopilación de datos no numéricos, mientras que la investigación cuantitativa tiene que ver con la recopilación de datos numéricos.

La investigación científica a menudo tiene que ver con la observación y la realización de inferencias. Este aspecto de la investigación científica es cualitativo.

Al mismo tiempo, es posible que también se requieran gráficos, tablas y cuadros para la presentación de datos en ciertos tipos de investigación científica. Esta es ahora una investigación cuantitativa.

Por tanto, la investigación científica es tanto cualitativa como cuantitativa

Acids increase the [tex]H^+[/tex] concentration in solution. Therefore, the correct option is D.

One of their essential characteristics is the ability of all acids to increase the concentration of H+ ions (protons) in a solution. Acids are chemicals that when dissolved in water add protons to the solution. As a result of this proton donation, the amount of [tex]H^+[/tex]ions in the solution increases, thereby lowering the pH. It is important to remember that not all acids contain[tex]H_3O^+[/tex] ions directly; Instead, [tex]H^+[/tex] ions can react with water molecules to generate [tex]H_3O^+[/tex] ions (hydronium ions).

Therefore, the correct option is D.

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Answer:

0.7atm

Explanation:

3.5/5 because constant temperature

Answer:

Among the given reactions,

a. Ag+FeCl 3

b, Zn + CaO

C. Ba+Na 2 CO 3

d . Cr+KNO3

which reaction is likely to take place based on the reactivity series?

Explanation:

The metal reactivity series is:

Li > K> Ba >Ca>Na > Mn > Zn > Cr> Fe> Cd Ni > H > Sb > Cu > Ag > Pd > Hg > Pt

The highly reactive metal will displace the less reactive metal from its compound during a displacement reaction.

a. Ag+FeCl 3

Ag is less reactive than Fe, so Ag cannot displace Fe from its compound.

This reaction also does not occur.

b, Zn + CaO

Zn is less reactive than Ca, so it cannot displace Ca from its compound.

This reaction does not occur.

C. Ba+Na 2 CO 3

Ba is more reactive than Na, so Ba displaces Na from its compound.

This reaction is possible.

d . Cr+KNO3

Cr is less reactive than K, so it cannot displace K from its compound.

Hence, This reaction is not possible.

Answer:

option c) Ba+Na 2 CO 3 -> BaCO3 +2Na

Answer:

Answer: A 0.20 M solution of HCl with a volume of 15.0 mL is exactly neutralized by the 0.10 M solution of NaOH with 3 mL volume.

Explanation:

Given: [tex]M_{1}[/tex] = 0.20 M,      [tex]V_{1}[/tex] = 15.0 mL

[tex]M_{2}[/tex] = 0.10 M,            [tex]V_{2}[/tex] = ?

Formula used is as follows.

[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]

Substitute the values into above formula s follows.

[tex]M_{1}V_{1} = M_{2}V_{2}\\0.20 M ]times 15.0 mL = 0.10 M ]times V_{2}\\V_{2} = 30 mL[/tex]

Thus, we can conclude that a 0.20 M solution of HCl with a volume of 15.0 mL is exactly neutralized by the 0.10 M solution of NaOH with 3 mL volume.

Oxidation reaction

Hope this helps! :)

Answer:

Incorrect

Explanation:

X is the reactants

Y is the products

In an endothermic reaction where energy is absorbed, the enthalpy the products (Y) is always higher than the enthalpy of the reactants (X).

Enthalpy change (∆H) = products (Y) - Reactants (X)

For an endothermic reaction, the ∆H value should be positive.

Enthalpy change

The diagram sketched by the students shows the opposite. The diagram shows that the enthalpy of the products (Y) is lower than the enthalpy of the reactants (X). This will give a negative value of ∆H.

It represents an exothermic reaction rather than endothermic.

Therefore, the student is incorrect.

Answer:

D

Explanation:

Ionic bonds form when a metal and a nonmetal exchange electrons.

A) atoms with relatively similar electronegativities share electrons between them and form covalent bonds

B) the force that holds atoms together in a metallic substance is known as a metallic bond. such a solid consists of closely packed atoms....in short, the valence electrons in metals, unlike those of covalent bonds, are nonlocalized and capable of wandering relatively freely throughout the entire molecule

C) bonds formed between two nonmetals are mainly covalent bonds

.The characteristic that can be written in A only is that ionic bonds are "formed between an atom that tends to lose electrons and an atom that tends to gain electrons" option D.

Ionic or electrovalent bonds are bonds formed between oppositely charged ions which are formed by a gain or loss of electrons and these ions are held together by strong electrostatic forces of attraction.

Therefore, characteristic that can be written in A only is that ionic bonds are "formed between an atom that tends to lose electrons and an atom that tends to gain electrons" option D.

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A stent is a small mesh tube that holds open passages in the body, such as weak or narrow arteries.

Explanation:

To open an artery near the heart

just took the quiz

Answer:

Condensation is the process.

Answer:

[CO] = 0.2064M

[Cl2] = 0.0074M

[COCl2] = 0.3876M

Explanation:

Based on the reaction, Kc at 1000K is:

Kc = 255.0 = [COCl2] / [CO] [Cl2]

Where [] are concentrations at equilibrium

As the reaction is 1:1, the concentrations at equilibrium are:

[CO] = 0.5940M - X

[Cl2] = 0.3950M - X

[COCl2] = X

Where X is reaction coordinate

Replacing:

255.0 = [X] / [0.5940 - X] [0.3950 - X]

255.0 = X / 0.23463 - 0.989 X + X²

59.8307 - 252.195 X + 255 X² = X

59.8307 - 253.195 X + 255 X² = 0

Solving for X:

X = 0.605M. False solution because produce negative answers

X = 0.3876M. Right solution.

Replacing:

[CO] = 0.5940M - 0.3876M

[Cl2] = 0.3950M - 0.3876M

[COCl2] = 0.3876M

[CO] = 0.2064M

[Cl2] = 0.0074M

[COCl2] = 0.3876M

The concentration at equilibrium of CO is 0.2064 M, [tex]\rm Cl_2[/tex] is 0.0074 M, and [tex]\rm COCl_2[/tex] is 0.3876 M.

The initial concentration of CO = 0.5940 M

[tex]\rm Cl_2[/tex] = 0.3950 M

At equilibrium,

Let the concentration of formed [tex]\rm COCl_2[/tex] = x

Concentration of CO = 0.5940 - x M

Concentration of [tex]\rm Cl_2[/tex] = 0.3950 - x M

[tex]\rm K_c[/tex] = 255

[tex]\rm K_c[/tex] = [tex]\rm \dfrac{[COCl_2]}{[CO]\;[Cl_2]}[/tex]

255 = [tex]\rm \dfrac{x}{[0.5940-x]\;[0.3950-x]}[/tex]

(151.47 - 255x) (100.727-255x) = x

15,256 - 65,025 [tex]\rm x^2[/tex] = x

0 =  65,025 [tex]\rm x^2[/tex] +x - 15,256

x = [tex]\rm\dfrac{-b\;\pm\;\sqrt{b^2\;-\;4ac} }{2a}[/tex]

a = 65,025

b = 1

c = -15,256

x = 0.38 M

Thus, the concentration at equilibrium of CO is 0.2064 M, [tex]\rm Cl_2[/tex] is 0.0074 M, and [tex]\rm COCl_2[/tex] is 0.3876 M.

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Answer:

its answer is nitric acid...

Answer:

Dependent variable

Explanation:

In every experiment, there must be a dependent variable and an independent variable.

The independent variable is that variable that you have to manipulate in order to receive a response. E.g, in the experiment described in the question, the amount of sunlight a sunflower plant receives is the independent variable.

The dependent variable is the number of seeds produced. It is the response obtained by carefully manipulating the amount of sunlight

Answer: The statement the  [tex]n^{th}[/tex] shell holds a minimum number of [tex]2n^{2}[/tex] electrons is true.

Explanation:

The alphabet 'n' denotes the principal quantum number whose value can be equal to 1, 2, 3, and so on but can never be zero.

Basically, 'n' is the number of shell of an atom and total number of orbitals present in a shell is [tex]n^{2}[/tex].

Each orbital can hold up to a maximum of wo electrons. Hence, the [tex]n^{th}[/tex] shell can hold a minimum number of [tex]2n^{2}[/tex] electrons.

Thus, we ca conclude that the statement the  [tex]n^{th}[/tex] shell holds a minimum number of [tex]2n^{2}[/tex] electrons is true.

Answer:

aluminum chloride> potassium bromide> butanoic acid> sugar

Explanation:

Conductivity has to do with the ability of a solid to dissolve in solution leading to the formation of mobile ions which are the charge carriers in solution.

Strong electrolytes produce more ions in solution hence they have a higher conductivity.

Aluminum chloride produces four particles in solution hence it has the highest conductivity followed by potassium bromide which produces two particles in solution. Butanoic acid is a weak electrolyte which dissociates only to a small extent while sugar is a nonelectrolyte, it does not dissociate at all in solution.

The points on the y-intercepts are (0,y) whereas the point on the x-intercept are (x,0). Here the y-intercept of the function f(x) = -x + 2 is 2.

When the line touches the y-axis, we can say that these are y-intercepts. The y-intercept can be found out when x = 0. This represents the point at which the graph crosses through the y-axis. The y-intercept can also be referred as y-value.

In order to find the intercepts of any function, we must find the coordinates of the point where the function intersects the x and y axis. This can also be done by equating the independent or dependent variable value as 0 and then finding out the other value.

Here the given function is:

f(x) = -x + 2

When we put x = 0, then

f(x) = -0 + 2 = 2

Thus the y-intercept is 2.

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Answer:

In the case of an exothermic reaction, the reactants are at a higher energy level as compared to the products, as shown below in the energy diagram. In other words, the products are more stable than the reactants. Overall Δ H ΔH ΔH for the reaction is negative, i.e., energy is released in the form of heat.

Explanation:

A plane mirror is a flat piece of glass that reflects an image that is identical (or nearly identical) to the object in front of it.

Answer:

The total energy, i.e. sum of kinetic and potential energy, is constant.

i.e. E = KE + PE

Initially, PE = 0 and KE = 1/2 mv^2

At maximum height, velocity=0, thus, KE = 0 and PE = mgh

Since, total energy is constant (KE converts to PE when the ball is rising),

therefore, KE = PE 

or, 1/2 mv^2 = mgh

or, h = v^2 /2g = 13^2 / (2x9.8) = 8.622 m

Hope this helps.

Answer:

Sodium is very reactive in nature. When exposed in air, it automatically forms Na2O. When it is put in water it reacts vigorously and starts burning on water. Due to the above reasons Sodium is called an active metal

Explanation: hope this helps pls mark as brainliest ty

Answer:

the solution becomes less concentrated... meaning there is a decrease in acidity ...hence the pH slightly increases as lesser ph

means more acidity

Answer:

The lithosphere is the most outer solid portion of

he most outer solid portion ofthe planet Earth.

crust is the outermost layer of earth.

Respuesta:

Cr₂S₃O₁₂

Explicación:

Primer paso: Dividir el porcentaje en masa de cada elemento por su masa atómica

Cr: 26,53/52 = 0,510

S: 24,52/32 = 0,766

O: 48,96/16 = 3,06

Segundo paso: Dividir todos los números por el más pequeño (0,510)

Cr: 0,510/0,510 = 1

S: 0,766/0,510 = 1,5

O: 3,06/0,510 = 6

Tercer paso: Multiplicar todos los números por algún número que haga que todos sean enteros (2)

Cr: 1 × 2 = 2

S: 1,5 × 2 = 3

O: 6 × 2 = 12

La fórmula empírica es Cr₂S₃O₁₂.

Answer: The empirical formula of the compound becomes [tex]Cr_2S_3O_{12}[/tex]

Explanation:

The empirical formula is the chemical formula of the simplest ratio of the number of atoms of each element present in a compound.

Let the mass of the compound be 100 g

Given values:

% of Cr = 26.53%

% of S = 24.52%

% of O = 48.96%

Mass of Cr = 26.53 g

Mass of S = 24.52 g

Mass of O = 48.96 g

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

To formulate the empirical formula, we need to follow some steps:

Molar mass of Cr = 52 g/mol

Molar mass of S = 32 g/mol

Molar mass of O = 16 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of Cr}=\frac{26.53g}{52g/mol}=0.510 mol[/tex]

[tex]\text{Moles of S}=\frac{24.52g}{32g/mol}=0.766 mol[/tex]

[tex]\text{Moles of O}=\frac{48.96g}{16g/mol}=3.06 mol[/tex]

Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 0.510 moles

[tex]\text{Mole fraction of Cr}=\frac{0.510}{0.510}=1[/tex]

[tex]\text{Mole fraction of S}=\frac{0.766}{0.510}=1.5[/tex]

[tex]\text{Mole fraction of O}=\frac{3.06}{0.510}=6[/tex]

Multiplying the mole fraction of all the elements by 2, in order to make it as a whole number

[tex]\text{Mole fraction of Cr}=(2\times 1)=2[/tex]

[tex]\text{Mole fraction of S}=(2\times 1.5)=3[/tex]

[tex]\text{Mole fraction of O}=(2\times 6)=12[/tex]

The ratio of Cr : S : O = 2 : 3 : 12

Hence, the empirical formula of the compound becomes [tex]Cr_2S_3O_{12}[/tex]

Answer:

a.endothermic reaction