Which of the following is a physical change?

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.

Answer:

The molar concentration of the H₂SO₄ solution is 0.28 M

Explanation:

Molar concentration = number of moles / volume in litres

Number of moles = molar concentration × volume

From the equation of reaction, molar ratio of acid to base = 1 : 2

Using the formula; Na/Nb = CaVa/CbVb

Where Na is the number of moles of acid; Nb = number of moles of base; Ca = concentration of acid; Va = volume of acid; Cb = concentration of base; Vb = volume of base; Na/Nb = mole ratio of acid to base

Substituting the given values in the equation:

1/2 = Ca × 25.18 / 0.93 × 14.92

Ca = 0.93 × 14.92/ 25.18 × 2

Ca = 0.28M

Therefore, the molar concentration of the H₂SO₄ solution is 0.28 M

The reduction of the species defines the gain of electrons. The iron is most likely to be reduced when reacts with zinc. Thus option A is correct.

Oxidizing agents are the species that gain electrons and get reduced, their oxidation number gets reduced when the metal reacts.

In the reactivity, series zinc is placed before iron and hence is a reducing agent that gets oxidized. Down the series, the reducing ability decreases while the oxidizing increases.

Therefore, option A. iron will be reduced when reacts with zinc.

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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%

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:

I think

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

the answer is silicon!!

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:

Ka = 3.45x10⁻⁶

Explanation:

First we calculate [H⁺], using the given pH:

To solve this problem we can use the following formula describing a monoprotic weak acid:

We input the data that we already know:

And solve for Ka:

Answer:

Density and rigidity

Answer:

Danger

Explanation:

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:

Endothermic

Explanation:

Endothermic reaction is one in which the enthalpy increases. What this implies is that, it is a closed system which absorbs heat from its surroundings and thus after reaction become cooler than prior to the reaction.

In this case, the mixture of the two liquids feel colder to touch. Thus, it is an endothermic reaction from the definition earlier given.

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:

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:

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:

Li(s) + H2O(l) -----> LiOH(aq) + H2(g)

Ca(s) + 2H2O(l) ---------------> Ca(OH)2(aq) + H2(g)

Explanation:

Metals react with water to yield the metal hydroxide and hydrogen gas as shown in the answer above.

The reaction equations were balanced, the number of atoms of each element on both side of the reaction equation is exactly the same.

This is the way to write a balanced reaction equation for the species shown in the question.

Answer:

so 0.15 moles X 22.4 dm3/mole=3.36 dm3. Next we find the moles of hexane combusted, and then the moles of CO2. Finally, we find the volume of CO2 using the fact that at STP, 1 mole of gas = 22.4 dm3.

Answer:

#6  8.67x10²⁴ atoms

#7  

1. Atom

2. Formula unit

3. Molecule

4. Ion

Explanation:

#6 First we calculate how many carbon moles are there in 7.00 moles of C₂F₂, keeping in mind that there are 2 C moles per C₂F₂ mol:

As for carbon dioxide, there are 0.400 C moles in 0.400 moles of CO₂.

We calculate the total number of C moles:

Finally we calculate the number of atoms in 14.4 C moles, using Avogadro's number:

#7

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.

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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.

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:

hydrogen, oxygen, chlorine, ammonia

Explanation:

Air is a mixture of gases. When we say "clean" air here, we are referring to air that does not contain pollutant gases.

Some components of air such as water vapour, methane, CO2, and N2O are greenhouse gases. They are known to contribute towards global warming.

Some gases such as SO2 and NO2 contribute towards acid rain. The oxides of nitrogen are particularly involved in the formation of photochemical smog.

The halogens are known to lead to the depletion of the ozone layer and radon is a radioactive gas.

Hence, hydrogen, oxygen, chlorine, ammonia have no negative environmental impact hence they are found in clean air.

Answer:

LICK

Explanation:

Answer:

d is the answer have a good one

Answer:

0.796 M

Explanation:

Step 1: Given data

Gravimetric concentration (Cg): 4.78 g%g

Density of the solution (ρ): 1.00 g/mL

Step 2: Calculate the volumetric concentration of the solution (Cv)

We will use the following expression.

Cv = Cg × ρ

Cv = 4.78 g%g × 1.00 g/mL = 4.78 g%mL

Step 3: Calculate the molarity of the solution (M)

The volumetric concentration is 4.78 g%mL, that is, there are 4.78 g of acetic acid per 100 mL of solution. We can calculate the molarity using the following expression.

M = mass solute / molar mass solute × liters of solution

M = 4.78 g / 60.05 g/mol × 0.1 L = 0.796 M

Answer:

because the have stronger electrostatic force

Answer:

option a

hope helps you

have a great day

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!