30.
Ionic compounds have very strong bonds and the compounds are often
in crystal structures.
True or false?

The limiting reactant is Cl₂ (chlorine).

Explanation:

We have the following chemical reaction:

2 Al (s) + 3 Cl₂ (g) → 2 AlCl₃ (s)

And we start with 2.7 g of Al and 3.12 g of Cl₂.

First we calculate the number of moles of each reactant.

number of moles = mass / molar weight

number of moles of Al = 2.7 / 27 = 0.1 moles

number of moles of Cl₂ = 3.12 / 71 = 0.044 moles

From the chemical reaction we see that 2 moles of Al are reacting with 3 moles of Cl₂ so 0.1 moles of Al are reacting with 0.15 moles of Cl₂ which is a quantity higher than our available one of 0.044 moles of Cl₂. The limiting reactant is Cl₂.

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Answer:

5$

Explanation:

Given data:

Number of tablets = 50

Cost = 25.00$

Number of tablets = 10

Cost = ?

Solution:

we will solve this problem through cross multiplication.

25/50 = x/ 10

x = 25/50×10

x = 0.5 × 10

x = 5

To find the cost of ten tabs of Clarithromycin 500mg, set up a proportion based on given information and solve for the cost.

To find the cost of ten tabs of Clarithromycin 500mg, we need to set up a proportion based on the given information.

If 50 tabs cost $25.00, then we can set up the proportion:

50 tabs / $25.00 = 10 tabs / x

Cross-multiplying, we get:

50x = 10 × $25.00

50x = $250.00

Dividing both sides by 50, we find that x = $5.00.

Therefore, ten tabs of Clarithromycin 500mg would cost $5.00.

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Answer:

P₂ = 0.7 atm.

Explanation:

Given data;

Initial Volume = 310 mL

Initial Pressure = 0.995 atm

Final volume = 440 mL

Final pressure = ?

Solution;

P₁V₁ = P₂V₂

P₂ = P₁V₁/V₂

P₂ =  0.995 atm . 310 mL / 440 mL

P₂ =  308.45 atm. mL /440 mL

P₂ = 0.7 atm.

9.33 units of NaCl

I did not say molecules because sodium chloride is not a molecule, it is an ionic compound.

Explanation:

To find the number of moles of NaCl we use the Avogadro's number to devise the following reasoning:

if          1 mole of NaCl contains 6.022 × 10²³ units of NaCl

then     X mole of NaCl contains 5.62 × 10²⁴ units of NaCl

X = (1 ×  5.62 × 10²⁴) / 6.022 × 10²³

X = 0.933 × 10

X = 9.33  units of NaCl

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Answer:

A hypothesis is an educated guess.

Answer:

The hypothesis is a educated guess that you take before starting an experiment.

Explanation:

If I do blank then blank will happen. If I drink water then I won't feel thirsty. It is something that makes you take a guess about what will happen.

Answer:

40%

Explanation:

Calculate the percent of the mass that is carbon:

[tex]\% mass = \frac{80}{200} \times 100 = 40\%[/tex]

The percent composition by mass of carbon in the compound is 40%.

To determine the percent composition by mass of carbon in the compound, one must calculate the ratio of the mass of carbon to the total mass of the sample, and then multiply by 100 to get the percentage.

The mass of carbon in the sample is given as 80.0 g. The total mass of the sample is the sum of the masses of carbon, hydrogen, and oxygen, which is 200.0 g (since the sample itself is 200.0 g).

The formula to calculate the percent composition by mass is:

[tex]\[ \text{Percent composition by mass} = \left( \frac{\text{mass of carbon}}{\text{total mass of the sample}} \right) \times 100 \] Substituting the given values into the formula: \[ \text{Percent composition by mass of carbon} = \left( \frac{80.0 \text{ g}}{200.0 \text{ g}} \right) \times 100 \] \[ \text{Percent composition by mass of carbon} = \left( \frac{2}{5} \right) \times 100 \] \[ \text{Percent composition by mass of carbon} = 0.4 \times 100 \][/tex]

                         [tex]\[ \text{Percent composition by mass of carbon} = 40\% \][/tex]

Therefore, the percent composition by mass of carbon in the compound is 40%.

Answer:

A

Explanation:

That's the best answer out of all of them.

Answer:the answer is a it makes the most sense and i tried looking at all of it and a actually made the most sense but umm yea its a

Answer:

Explanation:

The decrease of the freezing point is a colligative property, which means that it depends on the number of particles dissolved (solute particles).

The equation for the decrease of the freezing point is:

Where:

For all the given solutions the molality and Kf are the same. So, the difference is given by the van't Hoff factor.

The ideal van't Hoff factor is assumed to be equal to the number of ions into which a solute dissociates in solutions (for ionic solutes) and equal to 1 for covalent molecules.

Then, you must just need to use the dissociation equation for each solute:

Hence, the solution that will experience the lowest freezing point reduction is HOCH₂CH₂OH because it has the lowest van't Hoff factor, and that will be the solution with the highest freezing point.

Upon reacting 6 moles of copper(II) chloride with aluminum, 4 moles of aluminum chloride are produced according to the stoichiometry of the balanced equation.

When 6 moles of copper(II) chloride (CuCl₂) react with aluminum (Al), the balanced chemical equation is:

2Al + 3CuCl₂ → 2AlCl₃ + 3Cu

To find the number of moles of aluminum chloride (AlCl₃) produced, we use stoichiometry. The ratio of AlCl₃ to CuCl₂ in the balanced equation is 2:3.

Therefore, for every 3 moles of CuCl₂, 2 moles of AlCl₃ are formed. Given 6 moles of CuCl₂, we can set up a proportion:

(2 moles AlCl₃ / 3 moles CuCl₂) = (x moles AlCl₃ / 6 moles CuCl₂)

Solving for x gives us:

x = (2 moles AlCl₃ / 3 moles CuCl₂) x 6 moles CuCl₂ = 4 moles AlCl₃

So, 6 moles of CuCl₂ react to produce 4 moles of aluminum chloride.

The complete question is:

Aluminum reacts with copper(II)  chloride to make aluminum chloride and copper(a)2Al+3CuCl₂→2AlCl₃+3Cu. Given 6 moles of CuCl₂, how many moles of AICI, were made?​

Answer:

c = 4016.64 j/g.°C

Explanation:

Given data:

Mass of substance = 2.50 g

Calories release = 12 cal (12 ×4184 = 50208 j)

Initial temperature = 25°C

Final temperature = 20°C

Specific heat of substance = ?

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Solution:

Q = m.c. ΔT

ΔT  = T2 - T1

ΔT  = 20°C - 25°C

ΔT  = -5°C

50208 j = 2.50 g . c. -5°C

50208 j = -12.5 g.°C .c

50208 j /-12.5 g.°C =  c

c = 4016.64 j/g.°C

The specific heat of the substance is calculated using the formula [tex]Q = mc \Delta T[/tex], with given values of mass, heat, and temperature change. The result is a specific heat of 0.96 cal/g°C.

The specific heat is defined as the amount of heat per unit mass required to raise the temperature by one degree Celsius. The formula to calculate specific heat (c) when the heat (Q) is lost or gained is:

[tex]Q = mc \Delta T[/tex]

Where Q is heat in calories, m is mass in grams, c is specific heat in cal/g°C, and [tex]\Delta T[/tex] is the temperature change in Celsius.

Using the student's data:

Mass (m) = 2.50 g

Heat (Q) = -12 cal (negative because heat is released)

Temperature change ([tex]\Delta T[/tex]) = 20°C - 25°C = -5°C

Now, solving for c:

-12 cal = (2.50 g) c(-5°C)

c = -12 cal / (2.50 g imes -5°C)

c = 0.96 cal/g°C

Therefore, the specific heat of the substance is 0.96 cal/g°C.

Answer:

The density is : 0,75 g/cm3

Explanation:

We use the formula

density= mass/volume = 480 g/ 640cm3= 0, 75 g/cm3

Answer:

It demonstrates that it a physical change because you can't see nothing happening but something happening

Sry if it doesn't make sense

The given question is incomplete. The complete question is:

A chemistry teacher carried out several demonstrations, and students recorded their observations. For one of the demonstrations, a student concluded that a physical change took place, but not a chemical change. Which of the following observations could the student have made of the results of the demonstration?

a) Two colorless solutions were combined, and the resulting solution was pink.

b)  When a solid was added to a liquid, sparks were produced.

c) One piece of solid substance was changed into small pieces.

d) When two solutions were combined, a precipitate formed.

Answer: One piece of solid substance was changed into small pieces.

Explanation:

Physical change is defined as the change in which shape and size of a substance changes, There is no change in the composition of the substance as no new substance is forming. It is usually an reversible reaction.

Chemical change is defined as the change in which a change is the chemical composition takes place resulting in the formation of new substance. It is usually an irreversible reaction.

Indicators showing chemical changes are :

Color change

Characteristic odor

Formation of bubbles

Formation of precipitate

Thus the given change is a physical change as only the physical state i.e. size of solid substance was changed into small pieces.

Answer:

see attachment

Explanation:

Answer:

Iron can not form iron(i) selenide however it can form iron(ii) selenide.

Explanation:

The possible oxidation states of iron are +2 and +3.

Iron can form iron (ii) selenide.

The formula of iron (ii) selenide is FeSe.

In iron (ii) selenide the oxidation state of iron is +2.

The ratio of both atoms are 1:1.

Its molecular weight is 134.82 g/mol.

It is toxic compound.

Its melting point is 965°C.

Its density is 4.72 g/cm³.

Iron can also form iron (iii) selenide.

The formula of iron (iii) selenide is Fe₂Se₃.

In  iron (iii) selenide the oxidation state of iron is +3.

The ration of both atoms are 2:3.

It also known as ferric selenide.

Its molecular weight is 348.57 g/mol.

Answer:

The electron took two jumps to return to its ground state.

Explanation:

If the electron is in nth state then it first goes to (n-1)th to 2nd state and emits one photon of this energy gap. Then, it goes to ground state and emits another photon of different energy. It can emit [tex]\left \{ {{n-1} \atop {2}} \right.[/tex] types of different photons. Fourth option is incorrect because in that case it emits one photon and absorbs one photon to go back to that state and also both photons are of same energy.

Answer:

V₂  = 626.52 mL

Explanation:

Given data:

Initial volume = 268 mL

Initial temperature = 151 K

Final temperature = 353 K

Final volume = ?

Solution:

V₁ / T₁ = V₂ / T₂

V₂  = V₁  T₂/ T₁

V₂  = 268 mL× 353 K /  151 K

V₂  = 94604 mL.K / 151 K

V₂  = 626.52 mL

We want materials for the compressor that can withstand the high temperatures and pressures of refrigerants.

The most popular of these is air, and compressors are mechanical devices that are used to raise pressure in a range of compressible fluids or gases.

A compressor is a mechanical device that lowers a gas's volume while raising its pressure.

One particular kind of gas compressor is an air compressor. Pumps and compressors have characteristics in that both raise the pressure on a fluid and can move it via a pipe.

The air is forced into the storage tank by the vacuum and out of the chamber. The compressor shuts off once the storage tank reaches its maximum air pressure. The duty cycle refers to this procedure.

Therefore, Volume is decreased inside the compressor, causing an increase in pressure and Temperature.

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B

While nuclear energy does not pollute the environment, it poses the risk of radiation which is harmful to organisms because it causes lethal mutations.

Explanation:

Nuclear fission, for example, releases neutrons and other particles (at very high speeds) that can ionize materials including DNA. This will induce mutations of DNA most of which are usually lethal to organisms. Gamma and X- rays are also produced by fusion reactions and  if exposed to organisms also cause mutations on DNA through double stranded breaks. Therefore, the risk of an accident of a nuclear reactor can have immense ramifications on the ecosystems.

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Answer:

The correct answer is water.

Explanation:

During cellular respiration glucose molecules undergo complete oxidation to from energy in form of adenosine mono phosphate or ATP and metabolic waste products in form of Carbon monoxide(CO2) and water(H2O).

    According to the given question Callie expect seeds to give off water(H2O) as a waste product from performing cellular respiration.

molar concentration of Na⁺ ions = 3 M

molar concentration of CO₃⁻ ions = 1.5 M

First the water will solvate the sodium carbonate (Na₂CO₃).

Second the 80 mL of water added will dilute the first solution.

Explanation:

When you dissolve the Na₂CO₃ in water, the following solvation process takes place:

Na₂CO₃ (s) + H₂O (l) → 2 Na⁺ (aq) + CO₃⁻ (aq)

To find the final concentration of Na₂CO₃ solution we use the following formula:

concentration (1) × volume (1) = concentration (2) × volume (2)

concentration (2) = concentration (1) × volume (1) / volume (2)

concentration of Na₂CO₃ solution = 2.5 M × 120 mL / 200 mL

concentration of Na₂CO₃ solution = 1.5 M

molar concentration = number of moles / volume (L)

number of moles = molar concentration × volume (L)

number of moles of Na₂CO₃ = 1.5 M × 0.2 L = 0.3 moles

Knowing the solvation process we devise the following reasoning:

if         1 mole of Na₂CO₃ produces 2 moles of Na⁺ ions and 1 mole of CO₃⁻ ions

then   0.3 moles of Na₂CO₃ produces X moles of Na⁺ ions and Y mole of CO₃⁻ ions

X = (0.3 × 2) / 1 = 0.6 moles of  Na⁺ ions

Y = (0.3 × 1) / 1 = 0.3 moles of CO₃⁻  ions

molar concentration = number of moles / volume (L)

molar concentration of Na⁺ ions = 0.6 / 0.2 = 3 M

molar concentration of CO₃⁻ ions = 0.3 / 0.2 = 1.5 M

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Answer:

Your answer would be particles

Explanation:

The atom consist of subatomic particles like electrons protons and neutrons.

Answer:

A chemical test for starch is to add iodine solution (yellow/brown) and look for a colour change. In the presence of starch, iodine turns a blue/black colour

Explanation:

There is a golden role of solubility, polar solute dissolve in polar solvent and non polar solute dissolve in non polar solvent. Therefore, to identify the starch solution, we need to do iodine test.

Solutions are a homogeneous mixture of two or more substances. A solution is a homogeneous mixture of solvent and solute molecules. Solvent is a substance that is in large amount in solution. solute is the substance which is in small amount in a solution. There are two types of mixture that is homogeneous and heterogeneous. Solution is a homogeneous solution.

To know which one is starch solution amongst BaSO[tex]_4[/tex] and  MgO. Add iodine solution (yellow/brown) as a chemical test for starch and watch for a color change. The color of iodine changes to a blue/black color when starch is present.

Therefore, to identify the starch solution, we need to do iodine test.

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Explanation:

Since density is calculated with mass divided by volume, changing either of these variables will affect the density, not necessarily both of them. If only the volume is increased or only the mass is decreased, the density will decrease. If only the volume is decreased or only the mass in increased, the density will increase.

Example:

Original density is 50g/ml. Mass is 50g and volume is 1ml.

Increase mass only:

mass = 100g

Density = 100g/ml   <= Density is increased

Decrease mass only:

mass = 25g

Density = 25g/ml   <= Density is decreased

Increase volume only:

volume = 2ml

Density = 50g/2ml = 25g/ml   <= Density is decreased

Decrease volume:

volume = 0.5ml

Density = 50g/0.5ml = 100g/ml   <= Density is increased

Answer:

The given reaction is combustion reaction heat is also produced.

Explanation:

Chemical equation:

CH₄ + 2O₂  → CO₂ + 2H₂O

The given reaction is combustion of methane. When methane burn it produced water and carbon dioxide. Heat is also produced.

The given reaction followed the law of conservation of mass.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

Explanation:

This law was given by french chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

CH₄ + 2O₂  → CO₂ + 2H₂O

There are equal number of carbon hydrogen and oxygen atoms present on both side of equation. So it follow the law of conservation of mass.

Answer:

238,02891 grams

Explanation:

1g/mole

The mass in grams of 0.500 mol of uranium whose molar mass is 238.05 g/mol is 119.025g.

Mass of any substance will be calculated by using their moles by using the below formula as:

n = W/M, where

W = required mass = ?

M = molar mass of uranium = 238.05g/mol

n = moles of uranium = 0.5 moles

On putting values we get

W = (0.5)(238.05) = 119.025g

Hence required mass of uranium is 119.025g.

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Answer:

Add  limewater  

Explanation:

Ca(OH)₂ is about 1000 times more soluble than Mg(OH)₂

If you add limewater to the seawater, the magnesium ions will precipitate out as magnesium hydroxide.

Mg²⁺(aq) + 2OH⁻(aq) ⟶ Mg(OH)₂(s)

Answer:

C

Explanation:

All that is needed to do is combine like terms. The sign in front of each term stays with it. Like +9y-3y=6y, 7x would isolate itself since it has not other term to follow. And -6+4=-2. This would all lead to C. 7x+6y-2.

The expression simplifies to 7x + 6y - 2 by combining like terms, making answer choice C the equivalent expression.

The expression 7x + 9y - 6 - 3y + 4 can be simplified by combining like terms. First, combine the 'y' terms (9y - 3y) to get 6y. Then, combine the constant terms (-6 + 4) to get -2. After combining these terms, the expression simplifies to 7x + 6y - 2, which is answer choice C.

Density is the ratio of mass to volume. When one of these variables changes (mass or volume), density changes as well, due to them being directly or inversely proportional. Example: an inflated balloon floats because its volume increases (while mass stays constant), thus its density decreases.

The relationship between mass, volume, and density is defined by the formula: density = mass/volume. This means that density is the ratio of mass to volume.

When you change one of these values (mass, volume or density), the others change too, because they are directly or inversely proportional. For example, if you increase the mass of an object while keeping the volume constant, its density will increase. Conversely, if you increase the volume of an object while keeping its mass constant, its density will decrease.

A good example can be found in balloon: when you inflate a balloon, its volume increases while its mass remains nearly constant, resulting in a decrease in its density. That's why the balloon floats in the air (the air around being denser than the balloon).

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Answer:

F = 50000 N

Explanation:

The acceleration is rate of change of velocity of an object with respect to time.

Formula:

a = Δv/Δt

a = acceleration

Δv = change in velocity

Δt = change in time

Units:

The unit of acceleration is m.s⁻².

Acceleration can also be determine through following formula,

F = m × a

a = F/m

Given data:

Mass of car = 1250 Kg

Acceleration = 40 m/s².

Force = ?

Solution:

F = m × a

F = 1250 Kg ×  40 m/s²

Kg.m/s² = N

F = 50000 N

Answer:

0.2mol

Explanation:

mol = mass/mr

mass = 4.6g

mr = 23

mol = 4.6/23

= 0.2mol