Which two families of elements are soft and silvery and have low densities? Choose two.

Give a handwritten explanation and response. Estimate the expected melting temperature of cadmium (Cd), vanadium, and other elements based on the patterns you have found.

What does melting point mean?

The temperature at which a pure substance's solid and liquid states can coexist in equilibrium is known as the melting point. A solid's temperature will rise when heat is added to it until its melting point is reached.

How do melting and boiling points differ?

The melting point

The temperature that a quality of output into a liquid under normal air pressure is known as the melting point. The temperature at which a liquid's vapor pressure equals the pressure around it, turning the liquid into vapor (and vice versa).

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Answer

Explanation:

Magnesium Oxide has a formula of MgO.

Magnesium has a molar mass of 24.30g/mol and Oxygen has a molar mass of 15.99g/mol.

From this, we can say we are assuming a 1 mole sample of magnesium oxide, as the stoichiometric coefficients will always be the same, as will the ratio of oxygen to magnesium.

From this,

\(15.99g/mol *1 mol MgO = 15.99 gOxygen\\24.30g/mol *1molMgO=24.30gMagnesium\\Oxygen mass percent = 15.99/(15.99+24.30) = .396\)

The Magnesium equation will be the same but a different numerator. Notice, if there were different coefficients on the elements, you would have to multiply by the stoich coefficient.

The formula \(S = k ln(W)\) relates the disorder or randomness of a system to its temperature

Entropy is a measure of the disorder or randomness of a system. It can be defined using Boltzmann's constant \((k),\) which relates the energy of a system to its temperature.

The formula for entropy \((S)\) using Boltzmann's constant is:

\(S = k ln(W)\)

where W is the number of microstates that correspond to a given macrostate. In other words, W is the number of ways that a system can be arranged while still maintaining the same macroscopic properties, such as temperature, volume, and pressure.

Boltzmann's constant is a fundamental physical constant that relates the average kinetic energy of particles in a system to its temperature. It is defined as \(k = R/N_A,\) where R is the gas constant and \(N_A\) is Avogadro's number.

The natural logarithm of W \((ln(W))\) is a measure of the multiplicity of a system, or the number of possible arrangements of its particles. The higher the multiplicity, the more ways the system can be arranged, and the more disorder or randomness it has.

Therefore, through Boltzmann's constant and the number of possible arrangements of the system.

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Answer:

Explanation: When the Moon passes between Sun and Earth, the lunar shadow is seen as a solar eclipse on Earth. When Earth passes directly between Sun and Moon, its shadow creates a lunar eclipse. Lunar eclipses can only happen when the Moon is opposite the Sun in the sky, a monthly occurrence we know as a full Moon. Hope this helps and u have a good day <3

Here are the skeletal structures for the cyclopropane isomers with the molecular formula C5H10:

Isomer 1: N-butylcyclopropane

CH3-CH2-CH2-CH2-CH2

|

C

/

C---C

Isomer 2: Isobutylcyclopropane

CH3-CH(CH3)-CH2-CH2-CH3

|

C

/

C---C

Isomer 3: Neopentylcyclopropane

(CH3)3C-CH2-CH2-CH2-CH3

|

C

/

C---C

These structures represent the three possible isomers of cyclopropane with the given molecular formula. Each isomer has a different arrangement of atoms while maintaining the cyclopropane ring structure.

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Answer:

B: The colors of light emitted from heated atoms had very specific energies.

Explanation:

dont know if its the same question i had on edg but i think its B. Sorry if i didnt understand the question :)

Answer:

b

Explanation:

The volume of the sample after the reaction takes place is 8.42 L.

To determine the volume of the sample after the reaction takes place, we need to apply the concept of stoichiometry and use the mole ratios from the balanced chemical equation.

Given that 0.1800 mol of CO and 9.000×10^2 mol of O2 are present initially, we can calculate the limiting reactant by comparing the moles of CO and O2. The balanced equation shows that 2 moles of CO react with 1 mole of O2 to produce 2 moles of CO2. Therefore, the ratio of moles of CO to O2 is 2:1. Since there is an excess of O2, CO is the limiting reactant.Using the stoichiometry of the reaction, we can determine the number of moles of CO2 produced. Since the ratio of CO to CO2 is 2:2, the number of moles of CO2 formed is also 0.1800 mol.

Next, we apply the ideal gas law, assuming constant temperature and pressure, to calculate the volume of the sample after the reaction. Using the formula V = nRT/P, where V is the volume, n is the number of moles, R is the ideal gas constant, T is the temperature, and P is the pressure, we can rearrange the equation to solve for V. Since the temperature and pressure are constant, we can treat R, T, and P as constants.

By substituting the values into the equation, we have:

V1 = (0.1800 + 9.000×10^2) × (0.0821 × T) / P

V1 = (0.1800 + 9.000×10^2) × (0.0821 × T) / P

After the reaction, the number of moles of CO2 is 0.1800 mol. Therefore, the volume of the sample after the reaction is:

V2 = 0.1800 × (0.0821 × T) / P

Substituting the given values into the equation, we can solve for V2:

V2 = 0.1800 × (0.0821 × T) / P

Calculating the value of V2, we find that the volume of the sample after the reaction takes place is 8.42 L.

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Answer: A

Explanation: A

The portion of energy from the Sun that reaches the Earth​ is known as

electromagnetic spectrum.

Energy transfer from objects in space such as the Sun usually reach the

earth through the process known as radiation. The energy is referred to as

electromagnetic energy.

Components of the electromagnetic spectrum are:

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Answer: The statement that theatoms are made up of protons, neutrons, and electrons is not a part of Dalton's atomic theory. Therefore, option c is correct.

Explanation:

The  number of moles of CaCO3 and number of moles of CO2 produced by one tablet is 0.00974 mol.

Based on the given information, we can use stoichiometry to calculate the number of moles of CaCO3 in one tablet and the number of moles of CO2 produced.

To calculate the number of moles of CaCO3 in one tablet, we need to know the balanced chemical equation for the reaction between hydrochloric acid (HCl) and calcium carbonate (CaCO3):

CaCO3 + 2HCl → CaCl2 + CO2 + H2O

From the equation, we can see that 1 mole of CaCO3 produces 1 mole of CO2.

Therefore, the number of moles of CaCO3 in one tablet is equal to the number of moles of CO2 produced by the tablet.

The given information states that one tablet reacted with excess hydrochloric acid to produce 0.24 dm3 of carbon dioxide at r.t.p. We can convert the volume of CO2 to moles using the ideal gas law:

PV = nRT

where;

P is the pressure (which is 1 atm at r.t.p.),

V is the volume (0.24 dm3),

n is the number of moles of gas,

R is the gas constant, and

T is the temperature (which is 273 K at r.t.p.).

Rearranging the equation and solving for n, we get:

n = PV/RT = (1 atm)(0.24 dm3)/(0.08206 L·atm/mol·K)(273 K)

n = 0.00974 mol

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Answer:

See explanation

Explanation:

We know that photosynthesis involves the combination of carbon dioxide and water in the presence of sunlight to yield glucose.

If the atmosphere is rich in carbon dioxide such as  in a green house where air is filled with carbon dioxide, the rate of photosynthesis is increased.

As the rate of photosynthesis is increased, the growth of plants is also increased.

Hence, in a greenhouse where the air contains more carbon dioxide, the rate of plant growth increases.

Answer:

Chemistry provides an excellent foundation for careers in a variety of professions and occupations in academia, government, and industry, and in diverse fields such as environmental sciences, pharmaceuticals, medicine, materials, energy, oceanography, education, health, aerospace, law, and education.

Explanation:

Answer: Hi friend! Sorry if I'm incorrect but Chemistry can prepare you for many careers. Specifically in the scientific area.

Explanation:

If you're studying to get a Chemistry major. I think chemistry shows a way of objectifying and trying to find reasons in order to solve real world application problems. When you think about it chemistry is a guide to showing you current events, such as environment and technological advances.

Explanation:

To calculate the percent yield, we need to compare the actual yield to the theoretical yield. The theoretical yield is the amount of product that would be obtained if the reaction went to completion based on the stoichiometry of the balanced equation.

First, let's determine the molar mass of CaCO3 (limestone) and CaO (quicklime):

- Molar mass of CaCO3 = 40.08 g/mol (molar mass of Ca) + 12.01 g/mol (molar mass of C) + (3 * 16.00 g/mol) (molar mass of O) = 100.09 g/mol

- Molar mass of CaO = 40.08 g/mol (molar mass of Ca) + 16.00 g/mol (molar mass of O) = 56.08 g/mol

Next, we can calculate the theoretical yield of CaO:

The molar ratio between CaCO3 and CaO is 1:1 according to the balanced equation. Therefore, the mass of CaO produced is the same as the mass of CaCO3 used.

The theoretical yield of CaO is 3.3 × 10^3 g.

Now we can calculate the percent yield:

Percent Yield = (Actual Yield / Theoretical Yield) * 100

Percent Yield = (1 × 10^3 g / 3.3 × 10^3 g) * 100

Percent Yield = 30.30%

Therefore, the percent yield of CaO in this reaction is 30.30%.

The first solution provided by meguelratatouille came close to the correct answer, but erred in assuming that equal moles implies equal mass. The following discussion corrects this mistake.

To determine the percent yield, we must compare the actual yield to the theoretical yield.

Theoretical Yield

From the balanced chemical equation we have:

CaCO3(s) --> CaO(s) + CO2(g)

It is necessary to know the molar mass of CaCO3 and CaO to determine the amount of CaO produced from a given amount of CaCO3:

Molar mass CaCO3 = 100.09 g/mol

Molar mass CaO = 56.08 g/mol

Then, to find the total mass of CaO produced by 3.3 x 10^3 g of CaCO3 reactant, we calculate:

3.3 x 10^3 g CaCO3  
x 1 mol CaCO3 / (100.09 g/mol CaCO3)
x 1 mol CaO / (1 mol CaCO3)
x 56.08 g CaO / (1 mol CaO)
-----------------------------------
1848 g CaO

which we report as 1.8 x 10^3 g CaO after applying significant figures.

Actual Yield

Finally, the percent yield is given by dividing the actual yield by the theoretical yield we just computed:

(1 x 10^3 g) / (1.8 x 10^3 g) x 100% = 55.6% = 56%

The statement the catastrophe of polychroinated biphenyls (PCBs) gases released from a Union Carbide pesticide factory caused thousands of deaths and disabling conditions in Bhopal, India is TRUE.

Polychlorinated biphenyls (PCBs) are a group of man-made chemicals that were widely used in industry during the twentieth century. PCBs were used in a variety of industrial applications, such as as coolant fluids in transformers, capacitors, and other electrical equipment, as well as in hydraulic systems, heat transfer systems, and lubricants.

In addition, PCBs have been linked to a number of human health problems, including cancer, immune system dysfunction, neurobehavioral and developmental problems, reproductive and endocrine disorders, and other illnesses. Therefore, it is critical that all sources of PCBs be identified and safely eliminated or reduced to minimize people's exposure to this hazardous chemical.

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Answer:

magnesium carbonate reacts with aqueous acids to release carbon dioxide and water

MgCO3 + 2 HCl → MgCl2 + CO2 + H2O.

How to -

Step 1: Reaction

- Leave the dilute hydrochloric acid in a beaker.

- Add Magnesium carbonate slowly until it is in excess or until no more gas seem to be getting liberated.

Step 2: Filtration

- Filter with filter paper and funnel.

- Filter off the excess magnesium carbonate as magnesium chloride will be in aqueous form (liquid) and will come out with the filtrate. The residue is the excess magnesium carbonate.

Step 3: Crystallization to obtain solid crystals from the filtrate.

- Pour filtrate solution into evaporating dish/basin

- Provide heat using Bunsen burner

- Pour solution into an evaporating basin and heat over a water bath

- Stop heating when crystals start to form

allow water to evaporate until pure crystals remain.

- Dry crystals using absorbent paper or warm oven.

Precautions

- Use personal protective equipment such as gloves, a lab coat and wear eye protection, especially when heating.

- Avoid inhaling unnecessary gases during the whole process.

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Answer:

A) Ca(s) + C(s) + 3/2 O₂(g) → CaCO₃(s)

Explanation:

Standard enthalpy of formation of a chemical is defined as the change in enthalpy durin the formation of 1 mole of the substance from its constituent elements in their standard states.

The consituent elements of calcium carbonate, CaCO₃, in their standard states (States you will find this pure elements in nature), are:

Ca(s), C(s) and O₂(g)

That means, the equation that represents standard enthalpy of CaCO₃ is:

Is the equation that has ΔH° = -1207kJ/mol

When a particle of charge qq and mass mm moves in uniform electric and magnetic fields, its motion is described by the Lorentz force equation: F⃗ =q(E⃗ +v⃗ ×B⃗ )F→=q(E→+v→×B→), where F⃗ F→ is the net force on the particle, E⃗ E→ is the electric field, B⃗ B→ is the magnetic field, and v⃗ v→ is the velocity of the particle.

In this case, the electric field is e⃗ =e0k^e→=e0k^ and the magnetic field is b⃗ =b0k^b→=b0k^, so we can write the Lorentz force equation as F⃗ =q(e0k^+v0i^×b0k^)F→=q(e0k^+v0i^×b0k^). The particle's velocity at t=0 is given as v⃗ 0=v0i^v→0=v0i^, so we can substitute this value into the equation to get F⃗ =q(e0k^+v0j^b0)F→=q(e0k^+v0j^b0). This equation describes the motion of the particle in the given electric and magnetic fields. A particle with charge qq and mass mm moves in uniform electric (e⃗ =e0k^) and magnetic (b⃗ =b0k^) fields. At time tt=0, its initial velocity is v⃗ 0=v0i^.

Due to the electric field, the particle experiences a force F⃗ e=qqe⃗ , causing it to accelerate in the direction of the field. The magnetic force, F⃗ b=qq(v⃗ ×b⃗ ), acts perpendicular to both the velocity and magnetic field vectors. Since both field vectors are parallel (k^ direction), the magnetic force has no impact on the particle's motion. Therefore, the particle's trajectory will be influenced solely by the electric field.

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The atomic mass can be defined as the mass of neutrons and protons in the atom. The atomic mass of the oxygen isotope is 18 amu.

An atom is the smallest particle comprised of three subatomic units, namely electrons, protons, and neutrons.

The number of electrons in the atoms determines the atomic number, while the number of protons and neutrons determines the atomic mass.

The atomic mass can be given as:

\(\rm Atomic\;mass=Neutrons+Protons\)

The oxygen isotope has been comprised of 10 neutrons and 8 protons. The atomic mass of the isotope is given as:

\(\rm Atomic \;mass=10+8\;amu\\Atomic\;mass=18\;amu\)

The atomic mass of the oxygen isotope is 18 amu. Thus, option C is correct.

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Answer:

18 amu

Explanation:

atomic mass = #protons + #neutrons = 8 + 10 = 18 am

I think the answer is A. I know it's Planet X.

The atomic ratio of carbon to oxygen in carbon monoxide (CO) is 1:1, and the atomic ratio of carbon to oxygen in carbon dioxide (CO₂) is 2:1.

Firstly, we can analyze the decomposition of carbon monoxide (CO) and carbon dioxide (CO₂) to determine the atomic ratios involved.

Let's denote the atomic ratio of carbon to oxygen in carbon monoxide as x, and the atomic ratio of carbon to oxygen in carbon dioxide as y.

According to the given data;

Decomposition of carbon monoxide (CO);

Oxygen produced = 3.36 g

Carbon produced = 2.52 g

We know that the atomic mass of carbon is 12 g/mol, and the atomic mass of oxygen is 16 g/mol. Using these values, we can calculate the number of moles for each element;

Number of moles of oxygen = mass / atomic mass = 3.36 g / 16 g/mol = 0.21 mol

Number of moles of carbon = mass / atomic mass = 2.52 g / 12 g/mol = 0.21 mol

Since the atomic ratio of carbon to oxygen in carbon monoxide is x, we can write the following equation;

0.21 mol C / (0.21 mol O) = x

Simplifying the equation, we have;

x = 1

Therefore, the atomic ratio of carbon to oxygen in carbon monoxide is 1:1.

Decomposition of carbon dioxide (CO₂);

Oxygen produced = 9.92 g

Carbon produced = 3.72 g

Following the same calculations as before;

Number of moles of oxygen = mass / atomic mass = 9.92 g / 16 g/mol = 0.62 mol

Number of moles of carbon = mass / atomic mass = 3.72 g / 12 g/mol = 0.31 mol

Since the atomic ratio of carbon to oxygen in carbon dioxide is y, we can write the following equation;

0.31 mol C / (0.62 mol O) = y

Simplifying the equation, we have;

y = 0.5

Therefore, the atomic ratio of carbon to oxygen in carbon dioxide is 1:0.5, which can be simplified to 2:1.

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--The given question is incomplete, the complete question is

"Missed this? watch kcv: atomic theory; read section 2.3. you can click on the review link to access the section in your text. carbon and oxygen form both carbon monoxide and carbon dioxide. when samples of these are decomposed, the carbon monoxide produces 3.36 g of oxygen and 2.52 g of carbon, while the carbon dioxide produces 9.92 g of oxygen and 3.72 g of carbon. Calculate the atomic ratio of carbon to oxygen in carbon monoxide, and carbon dioxide."--

Answer:

Explanation:

Through respiration, carbon dioxide (CO2) is exhaled for the exchange of oxygen (O2) from the air. At the cellular level, O2 is used to convert biochemical energy from nutrients into adenosine triphosphate (ATP) with the production of CO2.

Answer:

The earlier bog bodies that were discovered in the 1600s might have not been preserved properly due to a lack of knowledge on how to preserve them or a lack of awareness of their significance. It is also possible that they might have decayed and decomposed over time and not survived till the present day. However, the bog bodies found after the late 1800s were preserved and studied extensively due to the increasing awareness and understanding of their historical and archaeological significance.

Explanation:

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The daughter nuclide when Ni-78 undergoes beta decay - option D. Ni-78 as beta decay cause a change in atomic number only.

Beta decay is the radioactive decay that emits a beta particle from an atomic nucleus. This causes not just beta particle but some gamma radiation as well. It is represented by \(\beta ^{-}\) and notation is ₋₁β⁰

Thus, the correct answer would be: option D. Ni-78 as beta decay cause a change in atomic number only.

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The first radioiodine isotopes to be used to treat thyrotoxicosis were iodine-130 and iodine-131 in 1941, and thyroid cancer was added to their list of uses in 1943.

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Answer:

The energy required is 8660.96 J.

Explanation:

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is the amount of heat that a body absorbs or releases without any changes in its physical state (phase change). This heat is given by the expression:

Q = c * m * ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case, you know:

Replacing:

Q= 4.18 \(\frac{J}{g*C}\) *74 g* 28 C

Solving:

Q= 8660.96 J

The energy required is 8660.96 J.

6H2 + P4 → 4PH3, is a balanced chemical reaction. The sum of the coefficients is 11.

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Answer

acidic

Explanation

The pH scale ranges from 0 to 14, with 7 being neutral. pHs less than 7 are acidic while pHs greater than 7 are alkaline (basic).

Hence, coffee has a pH of about 5 which means it is considered to be in the acidic range.

Answer:

B

Explanation:

This is the First Law of Thermodynamics which states that energy cannot be created or destroyed.