Hard water stains in sinks and showers can be caused by a buildup of solid calcium carbonate. These stains can be removed by bathroom cleaners containing acids such as aqueous hydrochloric acid, which reacts with the calcium carbonate to form carbon dioxide gas, aqueous calcium chloride and liquid water. a) Write a balanced equation for this reaction

Answer: 6 mol Li

Explanation:

The first step is to balance the equation.

2Li+Cl₂⇒2LiCl

We would need our conversions to find the amount of moles of Li needed to produces 6 mol LiCl.

[tex]6molLiCl*\frac{2molLi}{2molLiCl} =6molLi[/tex]

Answer:

The new temperature is 213.33 K

Explanation:

Charles's law indicates that the volume of gas at constant pressure is directly proportional to its temperature. This law indicates that if the temperature increases the volume increases and if the temperature decreases the volume decreases.

So, Charles's law is a law that says that when the amount of gas and pressure are kept constant, the ratio between volume and temperature will always have the same value:

[tex]\frac{V}{T}=k[/tex]

When you want to study two different states, an initial and a final one of a gas, the expression can be applied:

[tex]\frac{V1}{T1} =\frac{V2}{T2}[/tex]

In this case, you know:

Replacing:

[tex]\frac{15 L}{640 K} =\frac{5 L}{T2}[/tex]

Solving:

[tex]T2=\frac{5 L}{\frac{15 L}{640 K} }=\frac{5 L*640 K}{15 L}[/tex]

T2= 213.33 K

The new temperature is 213.33 K

Answer: 7.6 g of water are required to make 12.6 g of glucose

Explanation:

Moles is calculated by using the formula:

[tex]Moles=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

[tex]{\text {moles of glucose}}=\frac{12.6g}{180g/mol}=0.07moles[/tex]

The balanced chemical equation is:

[tex]6CO_2+6H_2O\rightarrow C_6H_{12}O_6+6O_2[/tex]

According to stoichiometry:

1 mole of glucose is produced by = 6 moles of water

Thus 0.07 moles of glucose is produced by =[tex]\frac{6}{1}\times 0.07=0.42[/tex] moles of water

Mass of water required =[tex]moles\times {\text {Molar mass}}=0.42mol\times 18g/mol=7.6g[/tex]

Thus 7.6 g of water are required to make 12.6 g of glucose

Answer:

0.136 L = 136 mL

Explanation:

18.0M = 18.0 mol/L

2.45 mol /(18.0 mol/L) = 0.136 L = 136 mL

Answer:

1) 0.4045nm

2) 0.0027096117g/cm³

Explanation:

1) Using the value of ionic radius of aluminum ion r=0.143 nm, the length of each edge of the unit cell can be calculated as what nm?

In the question above, using a face centered cubic structure, we have:

For a face centered site of the cube,

The diagonal = 4r

Where r =Atomic or ionic radius of Aluminum

Let the edge length of the cube be represented by X

Therefore, we have based on Pythagoras theorem,

X² + X² = (4r)²

2X² = 16r²

Divide both sides by 2

X² = 8r²

Find the square root of both sides

X = √8 × r

Since r = 0.143nm

The length of each edge of the unit cell can be calculated as

X = √8 × 0.143nm

X = 0.4044650788nm

Approximately = 0.4045nm

2) Using atomic weight value of aluminum 27.0, the density of aluminum can be calculated as what g/cm^3

Density of an object = Mass of the Object / Volume of the Object.

The object in this question = Cube

Step 1

Volume of a cube = (Length of the cube)³

In the question above, side length of the cube = 0.4045nm

When would convert 0.4045nm to centimeters

= 1 nm = 1 × 10^-7 cm

0.4045nm =

Cross multiply

= 4.045 × 10^-7 cm

Volume of the Aluminum cube =(4.045 × 10^-7cm)³

= 6.618439112 ×10^-20cm³

Step 2

The atomic weight value of aluminum is given as 27.0 in the question

A face centered cubic structure has 4 atoms per unit cell.

1 Atomic mass or weight value = 1.6605 × 10^-24 grams

Hence, the mass of Aluminum is calculated as:

(4 atoms /1 cell )× 1 unit × (27/ 1 atom of Aluminium) × (1.6605 × 10^-24g/ 1 Atomic mass value)

= 1.79334 ×10^-22g

Density = Mass/Volume

= 1.79334 ×10^ -22g /6.618439112 ×10^-20cm³

= 0.0027096117g/cm³

Answer:

Second graph is more reactive.

Explanation:

I just did the lesson myself, chose the first graph, and obviously got it wrong.

Therefore I can tell you with 100% certainty that the correct answer is graph #2 in this case.  Hope this helps.

Answer:

487 moles of CO2 is needed

Explanation:

What we need to use here is the ideal gas equation.

Mathematically;

PV = nRT

Since we are calculating the number of moles, we can rewrite the equation to be;

n = PV/RT

from the question, we identify the following;

P is the pressure at 150 atm

V is the volume at 80L

T is the temperature which is 27+273 = 300K

R is the molar gas constant which is 0.0821 L atm K^-1 mol^-1

Substituting these values, we have;

n = (150 * 80)/(0.0821 * 300) = 487.2 which is approximately 487 moles

Answer:

Ve explicación abajo

Explanation:

Responderemos esta pregunta en dos partes.

PAra la primera parte, usaremos la expresión de gases ideales la cual es:

PV = nRT (1)

Donde:

P: Presión (atm)

V: Volumen (L)

n: moles

R: constante universal de gases (0.082 L atm/ mol K)

T: Temperatura (K)

En este caso, tenemos un recipiente que se llena completamente de oxígeno (O₂) hasta 3 L. Este sería su volumen. a la presión de 740 mmHg, esta es la presión y debemos convertirla a atmosfera, y la temperatura de 10 °C que debe ser convertida a Kelvin. Con esos datos se puede calcular primero los moles de oxigeno y luego los gramos.

Transformando las unidades de presión y temperatura tenemos:

P = 740 mmHg * 1 atm / 760 mmHg = 0.974 atm

T = 10 + 273 = 283 K

Con estos datos, usaremos la expresión (1) para calcular los moles:

n = PV / RT

n = 0.974 * 3 / 0.082 * 283

n = 0.1259 moles

Con estos moles, se pueden calcular los gramos usando el peso molecular del oxigeno que es 16 g/mol. (Como tenemos 2 atomos, serían 32 g/mol):

m = n * PM

m = 0.1259 * 32

m = 4.0288 g

Ahora que tenemos la masa se puede calcular la densidad con la siguiente expresión:

d = m/V

Usando el volumen en mililitros (3 * 1000 = 3000 mL) y la masa obtenida, calculamos entonces la densidad.

d = 4.0288 / 3000

d = 0.00134 g/mL

Para la segunda y ultima parte del ejercicio, usaremos la ley de boyle donde se mantiene el volumen constante (en este caso 3 L) y solo se altera presión y temperatura. De esta forma calcularemos la temperatura necesaria para que la presión se reduzca a la mitad:

P₁/T₁ = P₂/T₂

Y queremos saber es la temperatura para que la presión sea la mitad de la presión inicial, por tanto:

P₂ = 1/2P₁

Sabiendo que la temperatura es de 10 °C (283 K) tenemos entonces:

P₁/T₁ = P₁/2T₂     Se cancelan las presiones y nos queda

1/T₁ = 1/2T₂

2T₂ = T₁

T₂ = 1/2T₁

Reemplazando la temperatura:

T₂ = 283 / 2

T₂ = 141.5 K

Answer: D

Explanation:

the atom of the metal loses one electron which becomes delocalised and is attragted by the positive nucleus leading to formation of metallic bond.

E. They form because electrons can move freely between atoms

Top guy is incorrect↑

#Platofam

Answer:

C6H6

Explanation:

Just use the table method to find the ratio of C to H and then compare the RMM with that of the empirical formula.

Answer:

C6H6

Explanation:

We divide each percentage by the relative atomic mass of the element:

Carbon:  92.31 / 12.011 = 7.68

Hydrogen:  7.69 / 1.008 = 7.63

So the ratio of carbon to hydrogen is 1:1.

Empirical formula is CH  - which has a  MM of 13.019

The RMM is 78 so the molecular formula = 78/13.019 = 6 * CH

So it is C6H6  (Benzene).

Answer:

-0.398

Explanation:

pOH is a measure of hydroxide ion (OH-) concentration in a solution. A basic solution If a solution has pOH less than 7 then it is a basic solution and if  pOH is greater than 7 then it is an acidic solution. Neutral solutions have pOH equal to 7.

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

To find pOH of 2.5 M NaOH, solve [tex]pOH=-\log \left [ 2.5 \right ][/tex] = -0.398

Answer:

Explanation:

The Kudzu is a plant that was introduced to the United States from Japan in the year 1876. In the United States it was introduced as an ornamental plant but with a reason which was to prevent soil erosion. Kudzu was disseminated as being high-protein content used to steer feed as well as a spreading plant to counteract soil erosion.

Answer:

Kudzu was introduced as an ornamental plant.

+

Kudzu was introduced as a way of preventing soil erosion.

So, A and D!

Answer:

C4H8. butene

Answer:

true

no explanation

Answer:

520mL

Explanation:

Data obtained from the question include:

Molarity of stock solution (M1) = 12M

Volume of stock solution (V1) = 130mL

Molarity of diluted solution (M2) = 3M

Volume of diluted (V2) =..?

The volume of the diluted solution can be obtained as follow:

M1V1 = M2V2

12 x 130 = 3 x V2

Divide both side by 3

V2 = 12 x 130 / 3

V2 = 520mL.

Therefore, 520mL of the diluted solution can be prepared.

Explanation:

Molarity = M = mol/1 liter

in sol 250 mL there are KNO3 2.02 mol

in sol 1000 mL there are KNO3 = 2.02/250 × 1000

= 8.08 mol/liter

Answer:

0.74M

Explanation:

Step 1 :

Data obtained from the question.

Initial concentration (C1) = 3M

Initial volume (V2) = 185mL

Final volume (V2) = 750mL

Final concentration (C2) =..?

Step 2:

Determination of the new concentration of the solution.

The new concentration of the solution can be obtained by using the dilution formula as shown below:

C1V1 = C2V2

3 x 185 = C2 x 750

Divide both side by 750

C2 = 3 x 185 / 750

C2 = 0.74M

Therefore, the new concentration of the solution is 0.74M

Answer:

Explanation:

Two possible changes are

Answer:

1) A

2) D

3) A

4) B

5) D

6) C

7) B

8) A

9) C

10) C

Explanation:

Sublimation refers to the direct change of a substance from solid to gas without passing through a liquid stage. Hence if camphor changes directly from solid to gas, camphor is a sublime substance.

Gases have a higher rate of diffusion than liquids because liquids have greater intermolecular forces while the intermolecular forces in a gas is negligible.

When a substance is heated, a point comes in which heat is supplied but the temperature of the body does not change. This is the point of phase change and the heat supplied at this point may be referred to as latent heat of fusion or vaporization depending on the particular process going on.

While it is true that evaporation occurs at all temperatures and the kinetic energy of molecules is directly proportional to the temperature of a body but the later statement does not explain the former. Rather evaporation occurs because some particles at the surface of the liquid are more energetic and escape due to unbalanced attractive forces acting on them.

Due to decrease in temperature, it takes a longer time to cook food at high altitudes but a lesser time to boil water at higher altitudes.

Gases are easily compressible by applying pressure because gases occupy negligible volume compared to the volume of the container. There is a significant inter particle space between gas particles.

The solid state contains the strongest degree of intermolecular forces. However, the reason offered, though correct, is not the correct explanation of the assertion stated.

This is the Tyndall effect. Colloidal particles scatter light rays and the path of the light becomes visible in the colloidal solution.

Salt solution is homogeneous. A homogeneous solution contains only one phase throughout. If it has a different composition, the solution is heterogeneous. Hence the explanation is false.

A true solution will not exhibit Tyndall effect because the particles are less than colloidal size. A true solution cannot be a heterogenous mixture hence the reason is false.

Answer:

the scientist who studied the movement of pollen grains grains suspended in water through a microscope is Robert Hooke

Answer:

THE pH OF THE SOLUTION IS 1.28

Explanation:

Step 1: Calculate the mass concentration of HCl

398 mg in 210 mL

1 L = 10^3 mL

1 g = 10^3 mg

398 *10^-3 g in 210 *10^-3 L

398 *10^-3 in 0.210 L

mass concentration = (0.398 * 1/ 0.210) g/dm3

= 1.895 g/dm3

Step 2: calculate the molar concentration

Molar mass of HCl = ( 1 + 35.5) = 36.5 g/mol

Molar concentration = mass concentration / RMM

Molar conc. = 1.895 / 36.5

Molar conc. = 0.0519 mol/dm3

So therefore, the molar concentartion of the solution is equal to the concentration of HCl.

In other words, [HCl] = 0.0519 mol/dm3

This shows that at 1 L of this solution contains 0.0519 moles of HCl

Step 3: write the dissiociation equation of HCl in water

HCl(aq) + H2O(l) --------> H30^+ (aq) + Cl- (aq)

Since HCl is a strong acid, it will dissociate completely in water forming the above products.

So we can say that:

[H3O+] = [HCl] = 0.0519 moles/ dm3

Step 4: calculate the pH

pH = -log[H3O+]

pH = -log (0.0519)

pH = 1.28(3 significant decimal place)

The pH of the solution is 1.28

Answer:

The geographical occurrence or spatial distribution of earthly resources made them abundant at some place and lacks at other.

Explanation:

Low latitudes regions receive more energy and plenty of rainfall from the sun, while higher latitudes obtain less energy from the sun and little rainfall. Metallic minerals are easily available in regions with strong tectonic activity, and fossil fuels are found in sedimentary rocks. The plains deliver flat landscapes and rich soil which is ideal for growing crops, on the other hand, steep hills and dry areas are more difficult for the activity. Therefore climate and geography play a vital role in the uneven distribution of natural resources across the globe.

Answer:

4 H2 + 1 O2 = 2 H2O

Answer:

Hope it helps you!

Answer Microbial oxidation of sulfur is the oxidation of sulfur by microorganisms to produce energy. The oxidation of inorganic compounds is the strategy primarily used by chemolithotrophic microorganisms to obtain energy in order to build their structural components, survive, grow and reproduce.

Explanation:

the le answer to dis problem is neon. it has 10 protons

Explanation:

All of that visible trail of radiation, especially in the form of gamma rays—the extremely energetic cousins of ordinary light. Astronomers have known for three decades that brilliant flashes of these rays, called gamma-ray bursts, arrive daily from random directions in the sky. Recently astronomers have pinned down the location of the bursts and tentatively identified them as massive supernova explosions and neutron stars colliding both with themselves and black holes. But even now nobody knows much about what goes on when so much energy is flying around. Matter grows so hot that it interacts with radiation in unfamiliar ways, and photons of radiation can crash into each other and create new matter. The distinction between matter and energy grows blurry. Throw in the added factor of magnetism, and physicists can make only rough guesses about what happens in these hellish settings. Perhaps current theories simply aren’t adequate to explain them.

Answer:

When a Magnesium Ribbon is burnt, a powdery substance called magnesium oxide is formed.

Explanation:

There has obviously been a chemical change because several chemical properties of the magnesium have been modified:  the color, the texture and the mass.

The increase in mass is due to the fact that oxygen from the air has combined with the magnesium to make magnesium oxide, MgO.

The chemical equation, Mg + O2  MgO shows this reaction but it needs to be balanced to make 2Mg + O2  2MgO.  

Using stoichiometry, we can convert this eqation into an equation with moles:  

2 mol Mg + 1 mol O2  2 mol MgO.  

Next, we convert to grams using atomic masses obtained from the periodic table:

48g Mg + 32g O2  80g MgO

Lastly, we determine the same thing in the proportions we used.  In other words, we used only 0.15g of Mg (not 48g) so everything needs to be divided by 320.  So 80 / 320 = 0.25 g.  If we burn 0.15 g of Mg, we obtain 0.25 g of MgO.

Hope this helps!!!

This is my first answer.

Answer:

8J

Explanation:

From the question, the gravitational stored energy is 8J.

So Mgh=8J.

The kinetic energy is ?

When we use the law of conservation of energy, as the apple is moving and about to it the ground, it has 0m speed.

Which means that the potential energy at rest i.e when the apple is on the ground is zero. When the apple is getting to the ground, KE +PE is conserves.

At the top of the tree, the Apple has zero potential energy because velocity is zero at rest and on hitting the ground, the apple has kinetic energy.

So, the maximum Kinetic energy is 8J.

Answer:

Magnesium

Explanation:

Using the KLMN styled electronic configuration, the electronic configuration of sulphur with atomic number 16 is 2, 8,6

What this means is that it needs extra 2 electrons to fill into its M shell to attain the octet configuration.

Now let’s look at Magnesium, with atomic number 12, the electronic configuration it has is 2,8,2.

This means it has 2 extra electrons to give away so as to attain its own stability.

The sulphur atom will gladly accept the two electrons which the magnesium atom wants to give away. This makes it the perfect element to be reacted with sulphur to make it attain its octet configuration