What is the formula of the compound Pentasilicon trioxide ?

Answer:

Scientific method.

Explanation:

Scientific method is the way taken to acquire scientific knowledge. It includes experiments, statistical analysis of existing data, and all kinds of observations of the world around us, while theoretical research is based on deriving certain theories about the world from basic principles, in a mathematical or logical way. The scientific method applies to both types of research, and emphasizes that scientific research is objective, that it can be verified by other scientists, and that knowledge is not acquired without context, but in a way that leads to a greater understanding of previous research and the world. we live in. To contribute to this, researchers are expected to clearly record both their findings and the methods they use to arrive at the results.

Answer:

1 ) Δs ( entropy change for hot block ) = - Q / th  ( -ve shows heat lost to cold block )

Δs ( entropy change for cold block ) = Q / tc

∴ Total Δs = ΔSc + ΔSh

                 = Q/tc - Q/th

2) ΔSdecomposition = Δh / Temp = ( 181.6 * 10^3 / 773 ) = 234.928 J/k

Explanation:

1) To show that heat flows spontaneously from high temperature to low temperature

example :

Pick two(2) solid metal blocks with varying temperatures ( i.e. one solid block is hot and the other solid block is cold )

Place both blocks for time (t ) in an insulated system to reduce heat loss or gain to or from the environment

Check the temperature of both blocks after time ( t ) it will be observed that both blocks will have same temperature after time t ( first law of thermodynamics )

Δs ( entropy change for hot block ) = - Q / th  ( -ve shows heat lost to cold block )

Δs ( entropy change for cold block ) = Q / tc

∴ Total Δs = ΔSc + ΔSh

                 = Q/tc - Q/th

2) Entropy change for Decomposition of mercuric oxide

2HgO (s) → 2Hg(l) + O₂ (g)

Δs = positive

there is transition from solid to liquid and the melting point of mercury ( the point at which reaction will take place ) = 500⁰C

hence ΔSdecomposition = S⁻ Hg  -  S⁻ HgO =

Δh of reaction = 181.6 KJ

Temp = 500 + 273 = 773 k

hence ΔSdecomposition = Δh / Temp = ( 181.6 * 10^3 / 773 ) = 234.928 J/k

Answer:

To transfer leftover solids to the filtration funnel and wash out crystals after recrystallization, ice cold methanol should be used (the mother liquor used for recrystallization).

Explanation:

Hope this helped

Answer:

Calcium

Explanation:

Zinc cannot displace Ca because calcium is above it in the reactivity series

Answer:

B. False

Explanation:

Water does NOT react too copper. Copper does not react with water because the oxygen in water is locked into a compound with one part oxygen and two parts hydrogen. Copper oxide is a compound from the two elements copper and oxygen. Everything else listed does but since water is on this list it is false.

Answer:

A fluid is a medium that has a defined mass and volume, but no fixed shape, at a constant temperature and pressure. This may include gases, liquids, plasmas, and to some extent plastic solids. A fluid can flow and deform, preventing it from carrying loads in a static equilibrium.  A fluid is always compressible and internal frictional forces always occur due to the viscosity of the fluid.

molarity = moles of solute / volume of solution

moles of solute = molarity × volume of solution

moles of solute = 0.245 mol/L × 0.1500 L

moles of solute = 0.03675 mol

moles of solute = 0.0368 mol

-----------------------------------------------------------

Step 1: Calculate the molar mass of solute.

molar mass of solute = (40.08 g/mol × 1) + (35.45 g/mol × 2)

molar mass of solute = 110.98 g/mol

Step 2: Calculate the mass of solute.

mass of solute = moles of solute × molar mass of solute

mass of solute = 0.03675 mol × 110.98 g/mol

mass of solute = 4.08 g

Note: The volume of solution must be expressed in liters (L).

Answer:

[tex]\boxed {\sf \bold {0.0368 \ mol \ CaCl_2}}}}[/tex]

[tex]\boxed {\sf \bold {4.08 \ g \ CaCl_2}}}}}[/tex]

Explanation:

Molarity is a measure of concentration in moles per liter.

[tex]molarity= \frac {moles \ of \ solute}{liters \ of \ solution}[/tex]

In this solution, there are 150.0 milliliters of solution and the molarity is 0.245 M CaCl₂ or 0.245 mol CaCl₂ per liter.

First, convert the milliliters to liters. There are 1000 milliliters in 1 liter.

Now, substitute the known values (molarity and liters of solution) into the formula. The moles of solution are unknown, so we can use x.

[tex]0.245 \ mol \ CaCl_2 /L= \frac{ x}{0.150 \ L}[/tex]

We are solving for x, so we must isolate this variable. It is being divided by 0.150 L. The inverse of divisions is multiplication, so we multiply both sides by 0.150 L.

[tex]0.150 \ L *0.245 \ mol \ CaCl_2 /L= \frac{ x}{0.150 \ L} * 0.150 L[/tex]

[tex]0.150 \ L *0.245 \ mol \ CaCl_2 /L=x[/tex]

The units of liters cancel.

[tex]0.150 *0.245 \ mol \ CaCl_2 =x[/tex]

[tex]0.03675 \ mol \ CaCl_2[/tex]

The original measurements have 3 significant figures, so our answer must have the same.

We should round to the ten thousandths place. The 5 to the right of this place tells us to round the 7 up to an 8.

[tex]\bold {0.0368 \ mol \ CaCl_2}[/tex]

We can convert mass to moles using the molar mass. These values are found on the Periodic Table. They are the same as the atomic masses, but the units are grams per mole (g/mol) instead of atomic mass units.

The solute is calcium chloride: CaCl₂. Look up the molar masses of the individual elements.

Notice that chlorine has a subscript of 2. We must multiply the molar mass by 2.

Add calcium's molar mass.

Use the molar mass as a ratio.

[tex]\frac {110.98 \ g\ CaCL_2}{ 1 \ mol \ CaCl_2}[/tex]

Multiply the moles of calcium chloride we calculated above.

[tex]0.0368 \ mol \ CaCl_2 *\frac {110.98 \ g\ CaCL_2}{ 1 \ mol \ CaCl_2}[/tex]

The units of moles of calcium chloride cancel.

[tex]0.0368 *\frac {110.98 \ g\ CaCL_2}{ 1 }[/tex]

[tex]4.084064 \ g\ CaCl_2[/tex]

Round to 3 significant figures again. For this number, it is the hundredths place. The 4 in the thousandths place tells us to leave the 8.

[tex]\bold {4.08 \ g \ CaCl_2}[/tex]

Answer:

d is the answer have a good one

Answer:

The air inside the Tyre causes pressure because the particles bump into each other and cause pressure the more they bump into each other or their container the higher the pressure is.

hope it is helpful for you

Answer:

I think

(d) All compounds contain the same elements in the same properties

Explanation:

The electron density number as well as the sublevel letter are used to describe valence electrons in an atom. The third total energy and subbasement p, for example, is denoted by 3p. The electron configuration of oxygen, for example, is 1s^2 2s^2 2p^4, which means the first two electrons will couple up in the 1s orbital, while the following two protons will pair up in the 2s orbital.

The sample atom is Carbon with electron configuration; 1s² 2s² 2p².

The principal energy level of an electron refers to the shellp in which the electron is located relative to the atom's nucleus. In this case only 2 energy levels exist in a carbon atom; which are energy level 1 and 2

The sublevels exist within a principal energy and the electron configuration of an atom is described with consideration of energy sublevels. The sublevels in a carbon atom are;

The orbitals in this configuration are: 1s 2s 2px 2py 2pz in which case; each orbital can accommodate 2 electrons each.

Ultimately, the location of an element on the periodic table with respect to group and period are used to determine the valency and no. of energy levels in the atom of that Element.

Read more:

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1) The order of decreasing priority would allow determining E/Z or R/S is "dbca".

2)  The order of decreasing priority would allow determining E/Z or R/S is "acbd".

Absolute configuration can be described as to the spatial arrangement of atoms within a chiral molecular entity. Absolute configuration in organic molecules, where carbon is bonded to four different substituents.

The absolute configuration has used a set of rules to describe the relative positions around the chiral center atom. The most common labeling method is the descriptors R or S where R and S refer to Rectus and Sinister.

The group with the highest atomic number will get the highest priority and the group with the lowest atomic number substituents will get the lowest priority. Therefore, the order of priority is -CH₂Br > -CH₂OH > -CH₂NH₂ > -CH₃.

Therefore, the order of priority for the second part is -F > -CHO > -CH₂OH > -CH₃.

Learn more about absolute configuration, here:

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the answer is silicon!!

Answer:

because the have stronger electrostatic force

Answer:

condensing water

Explanation:

Entropy refers to the level of disorderliness in a system. The entropy of liquids is greater than that of solids. The entropy of gases is greater than that of liquids.

A process of physical change involving a change of state from solid to liquid or liquid to gas is accompanied by increase in entropy.

However, a change of state involving a change from liquid to solid or gas to liquid is accompanied by decrease in entropy.

Hence, steam condensing to water leads to decrease and not increase in entropy of the system.

Answer:

B

Explanation:

Spontaneous in chemical reactions means without any external input.

Occurring without added energy. Hence, option B is correct.

A spontaneous reaction is a reaction that supports the formation of products under the conditions under which the reaction is happening.

Spontaneous Reaction- a reaction that favours the formation of products at the conditions under which the reaction is occurring.

A non-spontaneous reaction can be made spontaneous if it is inside a controlled environment, this is what happens in nuclear power plants that create atomic fusion and fission in chambers that are controlled to control different particles to create nuclear active rays.

Hence, option B is correct.

Learn more about the spontaneous reaction here:

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Answer:

2.9 × 10²⁴ atoms Cu; 3.3 × 10²¹ atoms C; 1.44 × 10²⁵ atoms Hg; 9.63 × 10²² atoms Na

Explanation:

To convert moles to atoms, we need a conversion factor: Avogadro's number. There are 6.02 × 10²³ atoms in 1 mole of atoms.

4.9 mol Cu × 6.02 × 10²³ atoms Cu/1 mol Cu = 2.9 × 10²⁴ atoms Cu

5.4 × 10⁻³ mol C × 6.02 × 10²³ atoms C/1 mol C = 3.3 × 10²¹ atoms C

24.0 mol Hg × 6.02 × 10²³ atoms Hg/1 mol Hg = 1.44 × 10²⁵ atoms Hg

0.160 mol Na × 6.02 × 10²³ atoms Na/1 mol Na = 9.63 × 10²² atoms Na

Answer:

Classify each of the following as either macroscopic, microscopic or particulate:

a. a red blood cell.

b. a sugar molecule.

c. baking powder.

Explanation:

a. A red blood cell is a microscopic particle.

It can be viewed under a microscope.

b. A sugar molecule is also a microscopic substance.

It can be viewed under a microscope.

c. Baking powder is macroscopic substance.

Answer: A balanced equation for the given reaction is [tex]NiO(s) + CO \rightarrow Ni(s) + CO_{2}(g)[/tex].

Explanation:

The reaction equation will be as follows.

[tex]NiO(s) + CO \rightarrow Ni(s) + CO_{2}(g)[/tex]

Number of atoms on the reactant side is as follows.

Number of atoms on the product side is as follows.

Since number of atoms on both the reactant and product sides are equal. Hence, the reaction equation is balanced.

Thus, we can conclude that a balanced equation for the given reaction is [tex]NiO(s) + CO \rightarrow Ni(s) + CO_{2}(g)[/tex].

Answer:

[tex]_{19} ^{40} K[/tex] → [tex]_{20} ^{40} Ca[/tex] + [tex]_{-1} ^{0} e[/tex] + ¯v

Explanation:

[tex]_{19} ^{40} K[/tex] is an unstable potassium isotope which has the capacity to undergo beta decay. During the decay process, it transforms to calcium atom with a release of beta particle and an antineutrino.

The required nuclear equation is:

                                              [tex]_{19} ^{40} K[/tex] → [tex]_{20} ^{40} Ca[/tex] + [tex]_{-1} ^{0} e[/tex] + ¯v

The calcium formed due to this process is a stable atom.

Answer:

The uncertainty principle is one of the most famous (and probably misunderstood) ideas in physics. It tells us that there is a fuzziness in nature, a fundamental limit to what we can know about the behavior of quantum particles and, therefore, the smallest scales of nature.

Answer:

Explained below.

Explanation:

In order to extract lead from lead oxide, we need to add carbon from coke to the lead oxide.

We will need;

A bunsen burner

A test tube

Charcoal

First step is to heat charcoal in an oxygen free environment. The safety measure here to ensure an oxygen free environment is to add some zinc metal powder into the test tube in order to remove any atmospheric oxygen inside the container.

Secondly, we will now put charcoal inside the test tube and turn on the bunsen burner to heat it until coke is formed.

Thirdly, we now introduce lead oxide into the coke inside the test tube and the carbon in the coke reacts with the lead oxide to produce lead and carbon dioxide.

Throughout all this process, since we required an oxygen free environment inside the test tube, whenever the test tube is opened, its neck must immediately be warmed by heat with the tube placed in a horizontal direction or very close to being in that horizontal direction so that any movement of air moves outwards from the tube.

it's 0.2cm different from the expected value, wich was 14.6cm

how many percent that are is calculated in the screenshot.

rounded it's 1.37%

The question is incomplete, the common question is;

What intermolecular attractive force is primarily responsible for the solubility of chlorine, Cl2, in water?

a. dipole - dipole

b. hydrogen bonding

c. dipole-induced dipole

d. ion-dipole

e. ion-induced dipole

Answer:

dipole-induced dipole

Explanation:

We have to remember that water is a polar molecule hence it possesses a dipole moment. Its dipole moment is responsible for the ability of water to dissolve many substances.

On the other hand, Cl2 is a nonpolar molecule bound together by only weak dispersion forces.

Recall that dispersion forces involve transient appearance of a dipole in a molecule.

Water molecules can induce a dipole in Cl2 thereby causing the both molecules to interact and Cl2 dissolves in water.

Answer:

39.0229 amu

Explanation:

Hello there!

In this case, according to given information, the idea here is to multiply the percent abundance by the mass number of each isotope and then add them all together as shown below:

[tex]=0.0967*38+0.7868*39+0.1134*40+0.0031*41\\\\=3.6746+30.6852+4.536+0.1271\\\\=39.0229amu[/tex]

Regards!

Answer:

option a

hope helps you

have a great day

The question is incomplete, the complete question is;

. A chemist determined by measurements that 0.015 moles of hydrogen chloride participate in a chemical reaction. Calculate the mass of hydrogen chloride that participates Round your answer to 2 significant digits. x S. ?

Answer:

0.54 g

Explanation:

Recall that;

Number of moles = mass/molar mass

Molar mass of HCl =36.5 g/mol

Mass= number of moles × molar mass

Mass= 0.015 moles × 36 g/mol

Mass= 0.54 g