Please help I will mark brainiest . When a student reacted 200. grams of aluminum chloride with calcium, she
produced 39.8 g of Al. What was her % yield?

Answer:

1.23 x 10²⁴ formula units K₂S

Explanation:

To find the amount of formula units in potassium sulfide, you need to (1) convert grams to moles (via the molar mass) and then (2) convert moles to formula units (via Avogadro's number). The conversions/ratios need to be arranged in a particular way that allows for the cancellation of units. Units are cancelled when then are located both in the numerator and denominator somewhere in the math. The final answer should have 3 sig figs because the given value (225 grams) has 3 sig figs.

Avogadro's number:

6.02 x 10²³ formula units = 1 mole

Molar Mass of K₂S:

110.26 g/mol

225 g K₂S           1 mole              6.02 x 10²³ units
----------------  x  -----------------  x  ----------------------------  = 1.23 x 10²⁴ formula units
                           110.26 g                    1 mole

Answer: all mass takes up space. everything has mass. Theres a unit of mass called a slug thats not the bug!

Explanation:

The major effect of stratospheric ozone layer depletion is an increase in the incidence of non-melanoma skin cancer.

This is because the ozone layer plays a crucial role in absorbing harmful ultraviolet (UV) radiation from the sun. When the ozone layer is depleted, more UV radiation reaches the earth's surface, increasing the risk of skin cancer.

A constant drop of roughly 4% in the total amount of ozone in the Earth's atmosphere and a significantly bigger seasonal decrease in stratospheric ozone (the ozone layer) around the planet's poles are the two connected phenomena that make up ozone depletion, which have been detected since the late 1970s. The ozone hole is a term used to describe the latter event. Along with these stratospheric events, there are also polar tropospheric ozone depletion events that occur in the spring.

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The rate determining step is; \(Ce^{4+} (aq) + Mn^{2+} (aq) ----- > Ce{3+} (aq) + Mn^{3+} (aq)\). option A

We know that in any sequence of reactions, the rate determining step is the slowest step of the reaction. In this case, the rate determining step would be the step that is first order in the cerium IV and first order in the Mn II.

When we look at the sequence of the reactions, we can see that the rate determining step has been described above and it is quite easy to spot in the sequence as shown. This is the step that would have the orders predicted above.

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Answer:

beacuse it can form again after melted or destroied

Answer:

just use a calculator

Explanation:

duh

The given problems are related to isotopes for 1 st solution it is ¹²O isotope with 8 protons and electrons and for ³He there are 1 neutron ,2 electron and mass number is 3.

Isotopes are defined as substances having same number of protons but different number of neutrons.Number of protons is characteristic for determining position of elements in the periodic table.

Since,all isotopes have the same number of protons and hence have same position.They have similar chemical properties as they have same number of electrons.

They find applications in the field of nuclear medicine and oil and gas research . There are 2 types of isotopes : stable and unstable

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The balanced chemical equation is:

0.5C7H16 + O2 → 0.5CO2 + H2O

For balancing the chemical equation C7H16 + O2 → CO2 + H2O, we can use linear algebraic techniques. We need to determine the coefficients that balance the number of atoms on both sides of the equation.

Let's denote the coefficients for C7H16, O2, CO2, and H2O as a, b, c, and d, respectively.

The balanced chemical equation can be written as:

aC7H16 + bO2 → cCO2 + dH2O

To balance the carbon (C) atoms, we have:

7a = c (Equation 1)

To balance the hydrogen (H) atoms, we have:

16a = 2d (Equation 2)

To balance the oxygen (O) atoms, we have:

2b = 2c + d (Equation 3)

We have three equations (Equations 1, 2, and 3) and four unknowns (a, b, c, d). To solve this system of equations, we can write it in matrix form and find the solution using linear algebraic techniques.

The augmented matrix for the system of equations is:

[ 7 0 -1 0 | 0 ]

[ 0 0 0 -2 | 0 ]

[ 0 -2 2 -1 | 0 ]

By performing row operations to row-reduce the augmented matrix, we can obtain the solution:

[ 1 0 -0.5 0 ]

[ 0 1 -1 -0.5 ]

[ 0 0 0 0 ]

The solution to the system of equations is:

a = 0.5

b = 1

c = 0.5

d = 1

Putting the values of a,b,c, and d we get the balanced chemical equation as:

0.5C7H16 + O2 → 0.5CO2 + H2O

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A hockey player attempts to make goal by sliding the puck across  frictionless ice,  forces acting on the hockey puck as soon at it breaks contact with the stick is gravity.

Frictionless surface​ is surface with no resistance between a surface or substance and something that is moving along or through it.

As soon as hockey puck breaks contact with the stick,  only force acting on the puck is the force of gravity. As the ice is assumed to be frictionless, there is no frictional force acting on puck.

Normal force, which is the force exerted by ice on the puck perpendicular to surface of the ice, cancels out the force of gravity in vertical direction, but it does not affect the motion of puck in the horizontal direction. And finally, there is no contact force acting on puck as it is no longer in contact with the stick.

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Answer:

3

Explanation:

the half life of a radioactive isotope is the amount of time one half of the isotope takes to decay

after 5 minutes the mass will be 24

after 10 minutes the mass will be 12

after 15 minutes the mass will be 6

after 20 minutes the mass will be 3

The kinetic energy is 0.5177 × 10⁻²¹ J more at 50°C compared to 25°C.

The average kinetic energy of a molecule is directly proportional to the absolute temperature of a gas.

KE = ( 3/2 ) ( R / Nₐ ) T

Where T is the temperature of the molecule, R is the gas constant, and Nₐ is Avogadro's number.

Now, R = 8.314 J/mol.K

Avogadro's number, Nₐ = 6.022 × 10²³ atoms/ mol

The average kinetic energy at 50° C is:

T = 50° C = 323 K

KE₁ = ( 3/2 ) × ( R / Nₐ ) × T₁

KE₁ = ( 3 × 8.314 × 323 ) / ( 2 × 6.022 × 10²³ )

KE₁ = 668.90 × 10⁻²³ J

KE₁ = 6.6890 × 10⁻²¹ J

The average kinetic energy at 25°C is:

KE₂ = ( 3/2 ) × ( R / Nₐ ) × T₂

KE₂ = ( 3 × 8.314 × 298 ) / ( 2 × 6.022 × 10²³ )

KE₂ = 617.13 × 10⁻²³ J

KE₂ = 6.1713 × 10⁻²¹ J

Now,

The average kinetic energy of the molecules at 50° C compared to 25° C is:

KE = KE₁ - KE₂

KE = 6.6890 × 10⁻²¹ - 6.1713 × 10⁻²¹

KE = 0.5177 × 10⁻²¹ J

Hence, the average kinetic energy is 0.5177 × 10⁻²¹ J more at 50° C compared to 25° C.

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Answer:

Friction is the force that opposes the motion of a solid object over another. There are mainly four types of friction: static friction, sliding friction, rolling friction, and fluid friction.

Answer:

0.342 moles

145 moles

0.0239 moles

0.498 moles

Explanation:

To solve this you only need to follow this rule:

N = n x Na. For solving this questions, you just need to divide this values for Avogadro's Coasting, and it's done. Hope it helped!

Adaptability is the evidence which is used as an indicator of ecosystem health. An ecosystem's health is described metaphorically as being in good shape.

An ecosystem's health is described metaphorically as being in good shape. The health of an ecosystem can fluctuate due to a variety of factors, including fire, flooding, flooding, extinctions, invading species.

There is no set standard for what constitutes a healthy ecosystem; rather, the apparent health state of an ecosystem can change based on the health indicators used to analyse it and the social ambitions that are motivating the evaluation. Adaptability is the evidence which is used as an indicator of ecosystem health.

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There are approximately 6.63 x 10^23 atoms in the sample of nickel.

To determine the number of atoms in a sample of nickel, we need to use Avogadro's number, which states that one mole of any substance contains 6.022 x 10^23 particles (atoms, molecules, or ions).

Given that the sample contains 0.110 mol of nickel, we can multiply this value by Avogadro's number to find the number of atoms. Performing the calculation:

0.110 mol * (6.022 x 10^23 atoms/mol) ≈ 6.63 x 10^23 atoms

Therefore, there are approximately 6.63 x 10^23 atoms in the sample of nickel.

Avogadro's number allows us to establish a relationship between the number of moles and the number of atoms in a sample of a substance. It provides a fundamental constant for understanding the scale of the microscopic world and enables calculations involving the quantities of atoms or molecules. In this case, by multiplying the number of moles by Avogadro's number, we obtain the number of atoms present in the sample of nickel.

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Answer:

21

Explanation:

2 + 2 = 21

The major product of electrophilic addition of HBr to an alkene is an alkyl halide, specifically, a bromoalkane.

Electrophilic addition occurs when an electrophile (such as HBr) reacts with a nucleophile (such as an alkene). The reaction involves the breaking of the alkene's double bond and the formation of new single bonds with the electrophile's atoms. In the case of HBr, the hydrogen atom bonds with the less substituted carbon of the alkene (according to Markovnikov's rule), and the bromine atom bonds with the more substituted carbon, resulting in a bromoalkane.

When HBr is added to an alkene through electrophilic addition, the major product is a bromoalkane, where the bromine atom is bonded to the more substituted carbon of the alkene.

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B) False. The polymerization of hyaluronic acid is not decreased when arthritis is present. In fact, the opposite is true. Arthritis, particularly osteoarthritis, is associated with an increase in the polymerization of hyaluronic acid.

Hyaluronic acid is a naturally occurring substance found in the synovial fluid of joints. It plays a crucial role in maintaining joint health by providing lubrication and shock absorption. In healthy joints, hyaluronic acid exists as a high molecular weight polymer, forming a gel-like structure that helps to cushion and protect the joint.

However, in arthritis, there is a degradation of the joint tissues, including the breakdown of hyaluronic acid molecules. This leads to a decrease in the concentration of high molecular weight hyaluronic acid and an increase in lower molecular weight fragments. This change in the molecular weight distribution of hyaluronic acid is associated with the loss of its beneficial properties, such as reduced lubrication and increased joint inflammation.

To address this imbalance, medical treatments for arthritis often involve the administration of exogenous hyaluronic acid injections. These injections aim to restore the proper polymerization of hyaluronic acid in the joint, improving joint lubrication and reducing inflammation.

In summary, the statement that the polymerization of hyaluronic acid is decreased when arthritis is present is false. Arthritis is associated with a decrease in high molecular weight hyaluronic acid and an increase in lower molecular weight fragments, which disrupts the polymerization and function of hyaluronic acid in the joint.

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According to the stoichiometry of the given chemical equation, 13.9939 grams of NaOH would be made with 8.0465 g of Na.

Stoichiometry is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.

Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample. It is useful in balancing chemical equations and making solutions of different concentrations.As according to the given chemical equation 46 g sodium gives 80 g sodium hydroxide, thus,  8.0465 g of sodium will give 8.0465×80/46=13.9939 grams.

Thus, 13.9939 grams of NaOH would be made with 8.0465 g of Na.

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The number of valence electron pairs in the outermost shell, as determined by the valence shell electron repulsion theory (VSEPR), determines the molecular shape.

By analyzing the repulsion between bond electron pairs in the outermost electron shell, a process known as the molecular shape can determine the shape of a molecule. Because most physical and chemical properties are influenced by molecular shape, it is crucial to study molecular shape or geometry.

The foundation of VSEPR is minimizing the strength of the electron-pair repulsion surrounding the central atom under consideration. The foundation of the VSEPR theory is the notion that the geometry (shape) of a molecule is primarily determined by the repulsion between the pairs of electrons surrounding a central atom.

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You should probably rephrase this:

According to Coulomb's Law, as the number of protons in an atom increases (or atomic number), the nuclear energy of atoms will increase, pulling electrons closer.

I think the order would be Be, Li, K but feel free to check online before you submit any work with this.

Due to an increase in the number of electrons, Group 17 elements become less volatile as they move down the group.

Simply put, an element is any substance that cannot be converted into another substance. Each of the approximately 150 elements has a unique form of atom. Atoms from at least two atom, and maybe more, are present in every item in the cosmos. Every known element is listed in the periodic table, and related elements are grouped together.

A fundamental object that is difficult to divide into smaller bits is known as an ingredient. An element is anything that cannot be broken by quasi reactions in chemistry and physics. One of humanity's most beneficial components to humanity is silicon.

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Answer:

77.5 grams of Na2O

Explanation:

Convert grams to mols.

1.06 x 10^2 grams x 1 mol NaOH/39.99

= 2.50 mols NaOH

Find the mole ratio of NaOH and Na2O

1:2

Convert mols NaOH to Na2O mols

2.50 mols NaOH x 1 mol Na2O/2 mols NaOH

= 1.25 mols Na2O

Convert to grams

1.25 mols Na2O x 61.98 grams Na2O/1 mol

= 77.5 grams Na2O required to produce 1.06 x 10^2 grams of NaOH

Answer:

Hi! I hope you're having a wonderful day, if not, I hope it gets better, much love and kindness! Be great!

Answer:

11.40x10-7

Explanation:

9.80+1.60x10-3-4

11.40x10-7

Answer:

The answer is

Explanation:

The density of a substance can be found by using the formula

\(d = \sqrt{ ({x1 - x2})^{2} + ({y1 - y2})^{2} } \\ \)

where

(x1 , y1) and (x2 , y2) are the points

From the question

mass of metal = 67.5 g

volume = 15 mL

The density of the metal is

\(density = \frac{67.5}{15} = \frac{9}{2} \\ \)

We have the final answer as

Hope this helps you

Answer:

(NH4)2SO4

Explanation:

2NH3(aq) + H2SO4 (aq) ---> (NH4)2SO4(aq)

Ammonia reacts with sulfuric acid to give the fertilizer ammonium sulfate.

The number of moles in container 2 is 33.3moles when the container has 27.32L of gas inside it

The number of moles of gas in container 2 can be calculated using the Ideal Gas Law:  

n = PV/RT  

where n is the number of moles of the gas with known volume,

P is the pressure (assumed to be 1 atm for ideal gases),

V is the volume (27.32 liters),

R is the ideal gas constant (0.0821 L·atm/mol·K) and

T is the temperature (assumed to be 273.15 K).  

Plugging in the values, we get:  

n = (1 atm)(27.32 L)/(0.0821 L·atm/mol·K)(273.15 K)

n = 33.3 mol  

Therefore, there are 33.3 moles of gas in container 2.

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