Which of the following provides a characteristic of
MgO(s) with a correct explanation?
Choose 1 answer:
А
It is hard because its ions are held together by strong
electrostatic attractions.
B
It is malleable because its atoms can easily move past
one another without disrupting the bonding.
It is a poor conductor of electricity because its
electrons are tightly held within covalent bonds and
lone pairs.
It has a high melting point because its molecules
interact through strong intermolecular forces.

Answer:

the volume of the titrant used

Explanation:

Acid-base titrations are usually depicted on special graphs referred to as titration curve. A titration curve is a graph that contains a plot of the volume of the titrant as the independent variable and the pH of the system as the dependent variable.

Hence, a titration curve is a graphical plot showing the pH of the analyte solution plotted against the volume of the titrant as the reaction is in progress. The titration curve is drawn by plotting data obtained during a titration, that is, volume of the titrant added (plotted on the x-axis) and pH of the system (plotted on the y-axis).

Answer:

C₃H1₂ +

Explanation:

just took the exam

Answer:

Lithium chloride (LiCl), carbon dioxide, and water

Explanation:

Li₂CO₃ + HCl ⇒ LiCl + CO₂ + H₂O

When lithium carbonate reacts with hydrochloric acid, lithium chloride, water, and bubbles of carbon dioxide gas are given off. This is the result of a double displacement reaction followed by a decomposition reaction.

Hope that helps.

Answer: D. Scientific investigation aims to design and implement an experiment to learn new information, whereas technological development aims to design a product to solve a problem.

Explanation:

Answer:

Temperature of the water

Explanation:

In every study, there must be independent and dependent variables. An independent variable is the variable that is changed in order to obtain a response. In this case, the temperature of the water is being changed, the response in this experiment is the respiration rate of the goldfish.

Thus the respiration rate of the goldfish is the dependent variable because it is controlled by the temperature of the water and changes accordingly.

Summarily, the independent variable is the temperature of the water while the dependent variable is the respiration rate of the goldfish.

Answer:

Each energy sublevel contains a different number of electrons. For example, sublevel D can contain up to 10 electrons

Explanation:

The atoms are surrounded by propellers that within each propeller there is a certain number of electrons, these electrons jump from orbit to orbit according to the amount of energy they have. The four levels that make up the electronic cloud that surrounds an atom are: s p d f.

When these electrons change orbit or level they release energy in the form of light, which is known as a photon.

Answer:

Explanation:

In all calorimetric experiment , the calorimeter must be isolated from the surrounding . Otherwise the heat change in the experiment can not be determined with precision .

The reaction is endothermic . Hence, there is lowering of temperature due to absorption of heat in the reaction equal to ΔH°. The value of ΔH° can be calculated by measuring fall in the temperature of the content . The fall in the temperature will be less when heat is allowed to come from the surrounding . Less fall of temperature will result in less ΔH° to be calculated .

Hence in the given experiment , if the student neglects to put lid on the cup , the experiment will give less value of ΔH°.

The solution is in the pictures because the picture is large, so I cut it and also put numbers on it to know it in sequence .

I hope I helped you^_^

Answer:

a) Monomers: monomers are unit molecules, that can react together with other monomers, to form a long chain molecule called a polymer. Th polymer formed can also be in a three dimensional network. The process of this conversion of monomers to polymers is called polymerization.

b) Repeating unit: A repeating unit is a unit of the polymer formed, whose repetition would produce a long complete polymer chain. A polymer is made up of these repeating links of molecules that form a long chain of molecules.

c) Condensation polymerization: This is a form of condensation reaction, that involves the combination of molecules into polymers with the loss of small molecules such as water or methanol as by products.

d) Cross-linked polymer: This is a polymer formed from a type of bonding of molecules. The bonding is usually in the form of covalent bonds or ionic bonds and the polymers can be either synthetic polymers or natural polymers.  The cross-links leads to an alteration in the physical properties of the polymer.

The definition of following terms are :

a) Monomers:

The monomers are unit atoms, that can respond in conjunction with other monomers, to create a long chain molecule called a polymer.

The polymer shaped can too be in a three dimensional arrange.

b) Repeating unit:

A rehashing unit may be a unit of the polymer shaped, whose reiteration would produce a long total polymer chain.

A polymer is made up of these rehashing joins of atoms that shape a long chain of molecules.

c) Condensation polymerization:

This is often a frame of condensation response, that includes the combination of particles into polymers with the misfortune of little particles such as water or methanol as by products.

d) Cross-linked polymer:

This can be a polymer shaped from a sort of holding of particles.

The cross-links leads to an modification within the physical properties.

Definition is a rhetorical style that uses various techniques to impress upon the reader the meaning of a term, idea, or concept.

Definition may be used for an entire essay but is often used as a rhetorical style within an essay that may mix rhetorical styles.

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Answer:

0.057 M

Explanation:

Step 1: Given data

Solubility product constant (Ksp) for HgBr₂: 2.8 × 10⁻⁴

Concentration of mercury (II) ion: 0.085 M

Step 2: Write the reaction for the solution of HgBr₂

HgBr₂(s) ⇄ Hg²⁺(aq) + 2 Br⁻

Step 3: Calculate the bromide concentration needed for a precipitate to occur

The Ksp is:

Ksp = 2.8 × 10⁻⁴ = [Hg²⁺] × [Br⁻]²

[Br⁻] = √(2.8 × 10⁻⁴/0.085) = 0.057 M

Answer:

1) The quantum number l can have values from

2 to 0

2)The total number of orbitals possible at the n = 3 energy level is 3'2=9

3) If the value of l = 3 ... The quantum number ml can have values from 3 to -3

The quantum number l determines the shape of the orbital.  In this case, if the value of n is 3, then the quantum number l can have values from 0 to (3-1), which is 2.

The total number of orbitals possible at the n = 3 energy level can be determined using the formula 2l + 1. So, for l = 0, there is 1 orbital. For l = 1, there are 3 orbitals. And for l = 2, there are 5 orbitals. Therefore, the total number of orbitals possible at the n = 3 energy level is 1 + 3 + 5 = 9.

On the other hand, the quantum number ml represents the magnetic quantum number. It specifies the orientation of the orbital in space. The value of ml ranges from -l to +l. So, if the value of l is 3, then the quantum number ml can have values from -3 to +3.

The total number of orbitals possible at the l = 3 sublevel can be determined using the formula 2ml + 1. So, for ml = -3, there is 1 orbital. For ml = -2, there is 3 orbitals. For ml = -1, there is 5 orbitals. For ml = 0, there is 7 orbitals. For ml = 1, there is 5 orbitals. For ml = 2, there is 3 orbitals. And for ml = 3, there is 1 orbital.

Therefore, the total number of orbitals possible at the l = 3 sublevel is 1 + 3 + 5 + 7 + 5 + 3 + 1 = 25.

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Answer:

While balancing a chemical equation, we change the coefficient  to balance the number of atoms on each side of the equation

Explanation:

While balancing a chemical equation, we change the coefficient to balance the number of atoms on each side of the equation.

To summarize in chemistry terms, a chemical equation depicts the initial chemicals, or reactants, on the left-hand side and the final compounds, or products, just on right-hand side, divided by an arrow. In the chemical equation, the number of atoms in each element as well as the total charge are the same on opposite of the equation's sides.

Chemical equations are used in chemistry to depict chemical processes by writing the reactants and products in terms of their corresponding chemical formulas. While balancing a chemical equation, we change the coefficient to balance the number of atoms on each side of the equation.

Therefore, while balancing a chemical equation, we change the coefficient to balance the number of atoms on each side of the equation.

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Answer:

1. Zinc sulfide : about the same solubility, no common ion is found.

2. Silver chloride : less solubility due to the presence of chloride ions provided by the 0.10 M hydrochloric acid.

3. Lead iodide  : about the same solubility, no common ion is found.

4. Silver hydroxide : about the same solubility, no common ion is found.

Explanation:

Hello,

In this case, we first must remember that adding a common ion (which is related with the dissolving solid) decreases the solubility of the insoluble solid due to the fact Le Chatelier's principle states the reaction will shift leftwards (reactants) to reestablish equilibrium, therefore, we have:

1. Zinc sulfide : about the same solubility, no common ion is found.

2. Silver chloride : less solubility due to the presence of chloride ions provided by the 0.10 M hydrochloric acid.

3. Lead iodide  : about the same solubility, no common ion is found.

4. Silver hydroxide : about the same solubility, no common ion is found.

Best regards.

Density measures how tightly packed particles are.

If particles are tightly packed together, they will be more dense.

If they are loosely together, they will be less dense.

However, a common mistake is thinking that if something

is more dense it means that it's heavier.

However, that's not the case.

It has to do with how particles are packed in an object.

The graph is not given in the question, so, the required graph is attached below:

Answer:

According to the graph, the relationship between the density of the sugar solution and the concentration of the sugar solution is directly proportional to each other as they both are increasing exponentially.

The graph shows that, the density of sugar solution will increase with the increase in concentration of sugar in the solution.

The concentration of H₂SO₄ is 0.78 M

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

H₂SO₄ + 2KOH —> K₂SO₄ + 2H₂O

From the balanced equation above,

Mole ratio of the acid, H₂SO₄ (nₐ) = 1

Mole ratio of the base, KOH (n₆) = 2

Finally, we shall determine the concentration of H₂SO₄. This can be obtained as follow:

Volume of base, KOH (V₆) = 72 mL

Concentration of base, KOH (C₆) = 9 M

Volume acid, H₂SO₄ (Vₐ) = 415 mL

Mole ratio of the acid, H₂SO₄ (nₐ) = 1

Mole ratio of the base, KOH (n₆) = 2

CₐVₐ / C₆V₆ = nₐ/n₆

Cₐ × 415 / 9 × 72 = 1/2

Cₐ × 415 / 648 = 1/2

Cross multiply

Cₐ × 415 × 2 = 648

Cₐ × 830 = 648

Divide both side by 830

Cₐ = 648 / 830

Therefore, the concentration of H₂SO₄ is 0.78 M

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Answer:

THE MASS OF NITROGEN GAS IN THIS CONDITIONS IS 0.0589 g

Explanation:

In an ideal condition

PV = nRT or PV = MRT/ MM where:

M = mass = unknown

MM =molar mass = 28 g/mol

P = pressure = 2 atm

V = volume = 25 mL = 0.025 L

R = gas constant = 0.082 L atm/mol K

T = temperature = 290 K

n = number of moles

The gas in the question is nitrogen gas

Molar mass of nitrogen gas = 14 * 2 = 28 g/mol

Then equating the variables and solving for M, we have

M = PV MM/ RT

M = 2 * 0.025 * 28 / 0.082 * 290

M = 1.4 / 23.78

M = 0.0589 g

The mass of the nitrogen gas at ideal conditions of 2 atm, 25 mL volume and 290 K temperature is 0.0589 g

Answer:

1.84 × 10⁻³

Explanation:

Step 1: Write the balanced equation

2 NOBr(g) ⇄ 2 NO(g) + Br₂(g)

Step 2: Calculate the initial concentration of NOBr

0.143 moles of NOBr(g) are introduced into a 1.00 liter container. The molarity is:

M = 0.143 mol / 1.00 L = 0.143 M

Step 3: Make an ICE chart

         2 NOBr(g) ⇄ 2 NO(g) + Br₂(g)

I             0.143               0           0

C              -2x               +2x        +x

E          0.143-2x            2x          x

Step 4: Find the value of x

The equilibrium concentration of NOBr(g) was 0.108 M. Then,

0.143-2x = 0.108

x = 0.0175

Step 5: Calculate the concentrations at equilibrium

[NOBr] = 0.108 M

[NO] = 2x = 0.0350 M

[Br₂] = x = 0.0175 M

Step 6: Calculate the equilibrium constant (Kc)

Kc = [0.0350]² × [0.0175] / [0.108]²

Kc = 1.84 × 10⁻³

ANSWER

I need great answers

EXPLANATION

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Answer:

1.49e24

Explanation:

Standars temperature and pressure are 273.15K and 1atm, respectively.

Using ideal gas law, we can find moles of an ideal gas if we know its pressure, temperature and volume as follows:

PV = nRT

PV / RT = n

Where P is pressure (1atm), V is volume (55.3L), R is gas constant (0.082atmL/molK), T is temperature (273.15K) and n moles of the ideal gas.

Replacing:

PV / RT = n

1atm*55.3L / 0.082atmL/molK*273.15K = n

2.47 moles = n

Now, the question is about the number of molecules in the jar. By definition, 1 mole = 6.022x10²³ molecules.

As we have 2.47 moles:

2.47 mol × (6.022x10²³ molecules / 1 mole) =

1.49x10²⁴ molecules that are in the jar

In scientific notation:

Answer:

Answer is A.

Explanation:

The indivisibility of an atom was proved wrong: an atom can be further subdivided into protons, neutrons and electrons. According to Dalton, the atoms of same element are similar in all respects. However, atoms of some elements vary in their masses and densities. These atoms of different masses are called isotopes. :)

Answer:

Weight 0.4326 g of sodium bicarbonate and 0.5141 g of sodium carbonate, dissolve it in distilled water and then bring the solution to a final volume of 50.0 mL using distilled water.

Explanation:

The pH of a buffered solution can be calculated using the Henderson-Hasselbalch equation:

[tex] pH = pKa + log(\frac{[Na_{2}CO_{3}]}{[NaHCO_{3}]}) [/tex]  

We have that pH = 10.3 and the Ka is 4.7x10⁻¹¹, so:

[tex] 10.3 = -log(4.7 \cdot 10^{-11}) + log(\frac{[Na_{2}CO_{3}]}{[NaHCO_{3}]}) [/tex]  

[tex] \frac{[Na_{2}CO_{3}]}{[NaHCO_{3}]} = 0.94 [/tex]  (1)

Also, we know that:

[tex] [Na_{2}CO_{3}] + [NaHCO_{3}] = 0.20 M [/tex]    (2)

From equation (2) we have:

[tex] [Na_{2}CO_{3}] = 0.20 - [NaHCO_{3}] [/tex]   (3)

By entering (3) into (1):

[tex] \frac{0.20 - [NaHCO_{3}]}{[NaHCO_{3}]} = 0.94 [/tex]

[tex] 0.94*[NaHCO_{3}] + [NaHCO_{3}] = 0.20 [/tex]

[tex] [NaHCO_{3}] = 0.103 M [/tex]  

Hence, the [Na_{2}CO_{3}] is:

[tex] [Na_{2}CO_{3}] = 0.20 - [NaHCO_{3}] = 0.20 M - 0.103 M = 0.097 M [/tex]  

Now, having the concentrations and knowing the volume of the buffer solution we can find the mass of the sodium carbonate and the sodium bicarbonate, as follows:

[tex]m_{Na_{2}CO_{3}} = C*V*M = 0.097 mol/L*0.050 L*105.99 g/mol = 0.5141 g[/tex]

[tex]m_{NaHCO_{3}} = C*V*M = 0.103 mol/L*0.050 L*84.007 g/mol = 0.4326 g[/tex]

Therefore, to prepare 50.0 mL of a 0.20 M solution that is buffered to a pH of 10.3 we need to weight 0.4326 g of sodium bicarbonate and 0.5141 g of sodium carbonate, dissolve it in distilled water and then bring the solution to a final volume of 50.0 mL using distilled water.      

I hope it helps you!

Answer:

[tex]\boxed {\boxed {\sf A. \ 2082 \ mL}}[/tex]

Explanation:

We are asked to find the initial volume of a gas given a change in pressure. Since the temperature remains constant, we are only concerned with volume and pressure. We will use Boyle's Law, which states the volume of a gas is inversely proportional to the pressure. The formula for this law is:

[tex]P_1V_1= P_2V_2[/tex]

The pressure was initially 248.71 millimeters of mercury, but the volume is unknown.

[tex]248.71 \ mm \ Hg * V_1 = P_2V_2[/tex]

The pressure is increased to 911.6 millimeters of mercury and the volume is 568 milliliters.

[tex]248.71 \ mm \ Hg * V_1 = 911.6 \ mm \ Hg * 568 \ mL[/tex]

We are solving for the initial volume, so we must isolate the variable V₁. It is being multiplied by 248.71 millimeters of mercury. The inverse operation of multiplication is division, so we divide both sides by 248.71 mm Hg.

[tex]\frac {248.71 \ mm \ Hg * V_1 } {248.71 \ mm \ Hg}= \frac{911.6 \ mm \ Hg * 568 \ mL }{248.71 \ mm \ Hg}[/tex]

[tex]V_1 = \frac{911.6 \ mm \ Hg * 568 \ mL }{248.71 \ mm \ Hg}[/tex]

The units of millimeters of mercury (mm Hg) cancel.

[tex]V_1 = \frac{911.6 * 568 \ mL }{248.71 }[/tex]

[tex]V_1 = \frac {517788.8} {248.71 } \ mL[/tex]

[tex]V_1 = 2081.897793 \ mL[/tex]

Let's round to the nearest whole number. The 8 in the tenths place tells us to round the 1 up to a 2.

[tex]V_1= 2082 \ mL[/tex]

The gas initially occupied a volume of 2082 milliliters and choice A is correct.

Answer:

The formula is:

Sn(ClO3)2

Tin(II) Chlorate is also called stannous chlorate and is a white-colored solid. Hydrates are the addition of water molecules. Tin (II) chlorate decahydrate is represented by Sn(ClO₃)₂ . 10 H₂O.

Hydrates are the chemical compounds used to represent the water molecule (H₂O) in a compound. The water molecules are added to the compound formula as a crystalline structure.

The element tin is represented by the symbol Sn and chlorate is represented as (ClO₃)₂. The formula also has decahydrate which means it has ten molecules of water that can be represented by 10 H₂O.

The stock nomenclature is used to give the formula for the compound. The overall formula of the compound after adding the individual symbol will give, Sn(ClO₃)₂. 10 H₂O.

Therefore, Sn(ClO₃)₂ . 10 H₂O is a formula for tin (II) chlorate decahydrate.

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Answer:

The r.a.m. value is used to determine how many isotopes an element has.

Explanation:

The method used to separate copper sulfate and water mixture was evaporation.

Explanation:

So, from this, we can conclude that the method used to separate copper sulfate and water mixture was evaporation.

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Answer:

Just did this on my test the answer is evaportion.

Explanation:

Answer:

whats the ph  ofpoh=9.78

Explanation:

Answer:

A : At the end of the hour, isotope B has a greater decay constant λ than isotope A

Explanation:

Firstly, we need to understand that radioactive decay follows a first order rate law.

What this means is that we can calculate the radioactive decay constant using the following formula from the half-life

Mathematically;

[tex]t_{1/2}[/tex]  = 0.693/λ

where λ represents the radioactive decay constant.

Rearranging the equation, we can have

λ = 0.693/[tex]t_{1/2}[/tex]

Now, to have a fair level playing ground, it is best that the half-life of both isotopes are in the same unit of time(seconds)

For A, the half-life = 2.3 minutes which is same as 2.3 × 60 = 138 seconds

For B, the half-life is 24 seconds

Thus, at the end of the hour, the decay constant for isotope A will be;

λ = 0.693/138 = 0.0050 [tex]s^{-1}[/tex]

For isotope B, the decay constant will be;

λ = 0.693/24 = 0.028875  [tex]s^{-1}[/tex]

We can see that the decay constant of isotope B is higher than that of A at the end of the experiment