A sample of 22K gold contains the following: 22 g gold, 1.0 g silver, and 1.0 g copper. What is the percent gold in the sample? Group of answer choices

Answer:

a

Explanation:

Answer:

a

Explanation:

B.

Both use kinetic energy to produce electricity is a similarity between power plants that use water as an energy source and those that use wind as an energy source.

Explanation:

Kinetic energy Is the intrinsic energy that an object or substance possesses due to its motion. All power plants that use water as an energy source utilize the kinetic energy of water to produce electricity. For example, hydro-power plants use the kinetic energy of water flowing due to gravity. Tidal power plants utilize the kinetic energy of water flowing due to tidal changes and geothermal powerplants utilize the energy of steam-water ejecting underground through fissures.

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Air bags are used as protective equipment in vehicles in which nitrate mixtures are filled with low density because, to inflate the gas , it needs higher volume.

In the event of a collision, airbags inflatable cushions installed in vehicles protect the occupants from being hit by the interior of the vehicle or by outside objects like other vehicles or trees.

As soon as a crash occurs, sensors begin to measure the impact force. The sensors transmit a signal to the inflators to swiftly fill the bags with gas if the accident is severe enough.

As long as they don't deploy in the course of a collision, airbags typically don't require maintenance. The stitch density will be lower for the inflation of the nitrogen gas inside the airbag, so lower density flexible fabric, such as nylon 6,6, is used.

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Answer:

The nucleus of a sulfur atom contains 16 protons.

The nucleus of a chlorine atom contains 17 protons.

Explanation:

Atoms are arranged in the Periodic Table according to the number of protons in their nuclei — their atomic numbers.

A proton is an integral particle —  you can't have half a proton.

S and Cl are adjacent in the Periodic Table, so it is impossible to find an element that will fit between them.

Final answer:

The reaction is a decomposition reaction where sodium azide decomposes into sodium and nitrogen gas.

Explanation:

The type of reaction represented is a decomposition reaction. This is a chemical reaction where a single compound breaks down into two or more elements or simpler compounds. Sodium azide (NaN3) decomposes into sodium metal (Na) and nitrogen gas (N2). One mole of sodium azide (NaN3) has a molar mass of approximately 65 g/mol.

Therefore, if 23.4 g of sodium azide is used, the moles of nitrogen gas produced can be calculated using the molar mass and the stoichiometry of the reaction. At standard temperature and pressure (STP), one mole of any gas occupies approximately 22.4 liters. By using the stoichiometry of the balanced equation, one can determine the volume of nitrogen gas produced at STP from a given amount of sodium azide.

Answer:

                   Option-A (XY)

Explanation:

                    In this problem one should focus on the number of valence electrons present in each atom. Remember that in lewis structure the dots on an atom always show the valence shell electrons. In given statement;

The,

                   X has one valence electron. It means that it can loose this single electron to attain the noble gas configuration i.e.

                                          X°  →  X⁺  +  1e⁻

Similarly,

                 Y have seven valence shell electrons. Therefore, in order to complete the octet this atom will gain one electron i.e.

                                          ::Y:°  +  1 e⁻  →  Y⁻

Hence, we can conclude that X got stabilized by losing one electron and Y got stabilized by gaining one electron therefore, only one of each is required to form an ionic compound i.e.

Answer: Comparisons .

Answer:

c

Explanation:

the answer is comparisons

Answer:

heterogeneous catalyst

Explanation:

The reaction equation:

                        MnO₂[tex]_{s}[/tex]

         H₂O₂[tex]_{l}[/tex]         →             2H₂[tex]_{g}[/tex]     +   2O₂[tex]_{g}[/tex]

A catalyst is any species that speeds up the rate of chemical reactions. It does not get used up in the reaction but helps facilitate the rate by which two species combines.

In this reaction, MnO₂ is the catalyst used in this reaction.

The catalyst still remains at the end of the reaction.

  Now, we know that from the subscript, the reactant is in liquid phase, the products are in gaseous phase and the catalyst is in solid phase.

A catalyst in a reaction in a different phase with the reactants is called a heterogeneous catalyst.

Answer:

The answer is B. A heterogeneous catalyst is being used in the reaction.

Explanation:

Answer:

[tex]\frac{[SO3][NO]}{[SO2][NO2]}[/tex]

Option D is the right answer.

Explanation:

When the rate of the forward reaction equals the rate of the reverse reaction, the chemical reaction is in equilibrium. The equilibrium constant (Kc) is used to determine whether reaction is in the equilibrium or not.

Example:

aA+bB⇋cC+dD      

Equilibrium constant (Kc)  for this reaction will be

Kc = [tex]\frac{[C]^c [D]^d}{[A]^a [B]^b}[/tex]

In this equation, [A] and [B] are equilibrium reactant concentrations. [C] and [D] are equilibrium product concentration and a, b, c, and d are the stoichiometric coefficients of the balanced reaction.

In our reaction,

SO2(g) + NO2(g) = S03(g) + NO(g)

Kc or Keq will be

Keq = [tex]\frac{[SO3][NO]}{[SO2][NO2]}[/tex]

This equation is balanced without any stoichiometric coefficients.

​

A rock with a striped pattern is classified as a metamorphic rock because its characteristics indicate that it has been transformed under high heat and pressure, realigning its mineral structure.

When classifying a rock with stripes, it suggests a transformation under high heat and pressure which typically results in the reorientation of minerals within the rock. This description fits the formation process of metamorphic rocks. Therefore, any rock with a striped pattern is likely a metamorphic rock, as igneous rocks form from the cooling of magma or lava and would not have stripes, and sedimentary rocks are characterized by layers formed from deposited sediment and can sometimes contain fossils.

Final answer:

The rock in question should be classified as metamorphic due to its striped look, which is a result of high heat and pressure reorienting minerals within the rock, characteristic of metamorphism.

Explanation:

You would classify this rock as metamorphic because it has a striped look, which is indicative of the foliation process that occurs when a pre-existing rock is transformed due to high heat and pressure. This reorientation of minerals within the rock often gives it a layered or striped appearance, a characteristic feature of metamorphic rocks. Sedimentary rocks, while they also have layers, are formed from particles of pre-existing rocks or organic material that have been compacted and cemented together.

These can sometimes contain fossils, but it is the presence of distinct stripes from the reorientation of minerals that suggests a metamorphic origin in the case you've mentioned. Igneous rocks with large crystals are formed from magma that solidifies slowly beneath the Earth's surface, but these do not have the striped appearance associated with metamorphic rocks.

Answer: 1 mole Kr

Explanation: solution

83.80g Kr x 1mole Kr / 84 g Kr

= 0.997 or approximately 1 mole Kr

Answer:

1. 1.34g

2. 1.19g

3. 0.49g

Explanation:Please see attachment for explanation

The density of the unknown liquid is calculated by subtracting the weight of the empty beaker from the weight of the beaker with the liquid to obtain the weight of the liquid. This is then divided by the volume of the liquid (given as 10ml) to calculate the density, which is 0.77568 g/ml.

The subject of this question is density, a concept in chemistry frequently utilized in high school. To calculate the density of the unknown liquid, we subtract the weight of the empty beaker from the weight of the beaker with the liquid. This gives us the weight of the liquid alone, which equals 40.1825 grams - 32.4257 grams = 7.7568 grams. The volume of the liquid is given as 10 ml. Hence, the density (D) is calculated by dividing the mass (M) of the substance by its volume (V), i.e., D = M / V = 7.7568 grams / 10 ml = 0.77568 g/ml.

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Answer:

A) metallic elements in the same group

Explanation:

X and Y are are group one elements called Alkali metals that react with water to displace hydrogen gas.They have large electrode potential thus they are oxidized to form a metal ion while the water is reduced to hydroxide ions and hydrogen gas.The solution formed is a basic solution and the reaction is exothermic.Note that the reaction of Alkali metals with water is violently and explosively.

The unknowns, X and Y elements are most likelyto be metallic elements belonging to same group. Thus, option A is correct.

The metals are elements in the periodic table that have the tendency to lose electrons and form positive ions. The periodic table has been the arrangement of elements in group and periods.

The elements belonging to same group have similar chemical properties, as they have same number of valence electrons.

The given reaction results in the formation of same byproducts with equivalent ion formation.

The ions for the reaction has a positive charge with the loss of electrons from the atom.

Since, X and Y loses electrons and have similar chemical properties, the elements are likely to be metallic elements belonging to same group. Thus, option A is correct.

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Answer: 94.07%

Explanation:

Percentage yield can be calculated by the formula

%yield = Experimental yield/Theoretical yield x100

Experimental yield = 7.93g

Theoretical yield = 8.43

%yield = Experimental yield/Theoretical yield x100

%yield = 7.93/8.43 x 100 = 94.07%

Answer:

                     a)  2.53 × 10²³ molecules of O₂

                     b)  31.90 g of KCl

Explanation:

                  The balance chemical equation for given decomposition reaction is as follow;

                                   2 KClO₃ → 2 KCl + 3 O₂

Step 1: Calculate Moles for given amount of KClO₃;

                    Moles  =  Mass / M.Mass

                    Moles  =  34.35 g / 122.55 g/mol

                    Moles  =  0.280 moles of KClO₃

Step 2: Find out  moles of O₂ produced;

According to eq,

                  2 moles of KClO₃ produces  =  3 moles of O₂

So,

            0.280 moles of KClO₃ will produce  =  X moles of O₂

Solving for X,

                    X  =  0.280 mol × 3 mol / 2 mol

                     X =  0.42 moles of O₂

Step 3: Calculate No. of Molecules of O₂ as,

No. of Molecules  =  Moles × 6.022 × 10²³

No. of Molecules  =  0.42 mol × 6.022 × 10²³ molecules/mol

No. of Molecules  =  2.53 × 10²³ molecules of O₂

Step 1: Calculate Moles for given amount of KClO₃;

                    Moles  =  Mass / M.Mass

                    Moles  =  52.53 g / 122.55 g/mol

                    Moles  =  0.428 moles of KClO₃

Step 2: Find out  moles of KCl produced;

According to eq,

                  2 moles of KClO₃ produces  =  2 moles of KCl

So,

            0.428 moles of KClO₃ will produce  =  X moles of KCl

Solving for X,

                    X  =  0.428 mol × 2 mol / 2 mol

                     X =  0.428 moles of KCl

Step 3: Calculate Mass of KCl as;

                         Mass  =  Moles × M.Mass

                         Mass  =  0.428 mol × 74.55 g/mol

                         Mass  =  31.90 g of KCl

By calculating the number of moles of KClO3 and using the stoichiometric ratios in the balanced equation, we find that 34.35 grams of KClO3 will produce about 2.53 x 10^23 molecules of O2, and that 52.53 grams of KClO3 will form about 31.97 grams of KCl.

The first thing we should do is calculate the molar mass of KClO3 which is approximately 122.55 g/mol. Then, find the number of moles of KClO3 in each part of the question.

a. The number of moles in 34.35 grams of KClO3 is 34.35 g / 122.55 g/mol = 0.2803 mol. From our balanced equation we know we get 3 molecules of O2 for every 2 molecules of KClO3, so we get 0.2803 mol x (3/2) = 0.4205 mol of O2. In molecules, this is 0.4205 mol x Avogadro's number (6.022 x 10^23) = 2.53 x 10^23 molecules of O2.

b. For 52.53 grams of KClO3 we get a number of moles equal to 52.53 g / 122.55 g/mol = 0.4288 mol. Following the balanced equation, we get an equal amount of KCl, thus 0.4288 mol. In grams, this is 0.4288 mol x 74.55 g/mol (molar mass of KCl) = 31.97 grams of KCl.

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Answer:

2K + HgCl2 —> Hg + 2KCl

Explanation:

K + HgCl2 —> Hg + KCl

The above equation is not balanced

To balance the equation, do the following.

First, put 2 in front of KCl, the equation becomes,

K + HgCl2 —> Hg + 2KCl

Now we see that Cl is balanced but K is not. To balance K, put 2 in front of K as shown below:

2K + HgCl2 —> Hg + 2KCl

Now we can that the equation is balanced

As the ball falls towards the ground, its gravitational potential vitality is changed into active vitality. The dynamic vitality of an item is the vitality it has because of its movement.

Explanation:

As the ball falls towards the ground, its gravitational potential vitality is changed into active vitality. The motor vitality of an item is the vitality it has because of its movement. At the point when the ball has arrived at its absolute bottom, its potential vitality is zero, and its motor vitality is more noteworthy.

Since vitality can't be crushed, the ball's most prominent potential vitality is equivalent to its most prominent motor vitality. K.E. = J, which is, obviously, equivalent to its underlying potential vitality.

Final answer:

Dynamic equilibrium is characterized by a situation where the forward and reverse reactions occur at equal rates, leading to no net change in the concentrations of reactants and products, although both reactions are still taking place.

Explanation:

What is true of dynamic equilibrium? The answer is A: All the changes to a system cancel out. In a dynamic equilibrium, we have a situation where the rate of the forward reaction (e.g., A+B ightarrow C+D) is equal to the rate of the reverse reaction (C+D ightarrow A+B). This means that while reactions are still occurring in both directions, there is no net change in the concentrations of reactants and products - they remain constant over time. It is also important to note that the system must be closed, with no substances entering or leaving, and the amounts of reactants and products don't have to be equal, just constant post-equilibrium.

Answer:

that light is on the electromagnetic spectrum

Explanation:

this is because In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. Like all types of EM radiation, visible light propagates as waves. However, the energy imparted by the waves is absorbed at single locations the way particles are absorbed. The absorbed energy of the EM waves is called a photon, and represents the quanta of light.

Answer:

light is made of particles, called photons. Except their movement to earth, every photon vibrates in every direction (they vibrate in just one direction if light is polarized).

Explanation:

Answer:

Sodium (NA)

Explanation:

Answer:

rubidium: rb

Explanation:

Answer:

C D A B

Explanation:

Answer:

Acetic acid ([tex]CH_{3}COOH[/tex]) can release only one single H+ ion .

Therefore we can say that acetic acid has only one pKa value.

Amino acids have one -COOH( carboxylic group) group and one -NH​​​​​​2​ (amino group) group which can both release one single H+ ion.

Explanation:

Acetic acid ([tex]CH_{3}COOH[/tex]) can release only one single H+ ion .

Therefore we can say that acetic acid has only one pKa value.

Amino acids have one -COOH( carboxylic group) group and one -NH​​​​​​2​ (amino group) group which can both release one single H+ ion.

In amino acids  -[tex]NH_{2}[/tex] group becomes [tex]-NH_{3}^{+}[/tex] in the presence of acids.

in the presence of bases  [tex]-COOH[/tex] becomes [tex]-COO^{-}[/tex]

Therefore two pKa values can be observed amino acids.

Final answer:

Acetic acid has only one pKa value because it is a monoprotic acid with a single proton to donate, creating one acid dissociation constant. Amino acids have at least two ionizable groups (amino and carboxyl groups), each capable of donating a proton under different conditions, resulting in two distinct pKa values for amino acids.

Explanation:

The question asks: Why does acetic acid have only one pKa value and our amino acids have two? Acetic acid, which is a monoprotic weak acid, contains only a single acidic proton. As such, it can donate only one proton to the solution, leading to a single acid dissociation constant or pKa value. This is contrasted with amino acids, which generally possess at least two ionizable groups (the amino group and the carboxyl group). Each of these groups can donate a proton under different pH conditions, resulting in two distinct pKa values. The differences in pKa values are influenced by the structure of the ionizable group and its relative ability to stabilize the resulting conjugate base. For example, the carboxyl group of an amino acid has a pKa around 2, reflecting its readiness to donate a proton and form a carboxylate anion, which is stabilized through resonance. The amino group typically has a pKa around 9, indicating its ability to accept a proton and form an ammonium ion. The microenvironment surrounding these ionizable groups, especially in proteins, can further affect their pKa values, leading to a variability depending on factors such as whether the amino acid is exposed to solvent or buried within a protein structure.

Answer: B

.

Explanation:

Answer:

A - Because the model makes concepts easier to understand.

Explanation:

A visual representation can be a great help in figuring something out. Besides, the other answers don't make much sense.

Hope this helps! (and sorry it's late ^^'' )

Explanation:

There are some properties to demonstrate that this was a chemical change and not a physical change

[tex]1.985 \times 10^{24} \text { atoms }[/tex] is the calculated number of atoms in 75.8 g of Na

Explanation:

In order to go from mass of sodium to atoms of sodium, we have to do two things:

Step 1:

To calculate the number of atoms in a Na sample, divide its weight in grams by the amu atomic mass from the periodic table

We know the Molar mass of Na = 22.989770 g / mole

Given weight of Na in grams = 75.8 g

        [tex]75.8 g \times \frac{1 \mathrm{mole}}{22.989770 \mathrm{g}}=3.297 \mathrm{mole}[/tex]

Step 2:

Multiply the obtained result by Avogadro's number ([tex]6.02 \times 10^{23}[/tex])

       [tex]3.297 \text { mole } \times \frac{6.02 \times 10^{23} \text { atoms }}{1 \text { mole }}=19.85 \times 10^{23} \text { atoms }=1.985 \times 10^{23} \text { atoms }[/tex]

Answer:

78.4L

Explanation:

1 mole of any gas is found to occupy 22.4L at stp. This also indicates that 1mole of oxygen occupy 22.4L.

Therefore,

3.50 moles of oxygen Will occupy = 3.5x22.4 = 78.4L

At Standard Temperature and Pressure (STP), one mole of an ideal gas occupies around 22.4 liters. Accordingly, 3.50 moles of oxygen would occupy a volume of 78.4 liters.

The question is inquiring about the volume an ideal gas, in this case oxygen, would occupy at Standard Temperature and Pressure (STP) given its quantity in moles. It's well established in chemistry that at STP, which is defined as a temperature of 273.15 K and a pressure of 1 atm, one mole of any ideal gas occupies approximately 22.4 liters. This is often known as the standard molar volume. Therefore, to calculate the volume that 3.50 moles of oxygen would occupy, multiply the number of moles (3.50) by the volume of one mole (22.4 L/mole) which results in a volume of 78.4 liters.

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Answer:

Because there is a lesser if not absent atmospheric pressure on Mars relative to earth

Explanation:

On earth the liquid water will experience atmospheric downward pressure due to the earth's atmosphere which will require it to evaporate at a vapour pressure that is greater than the atmospheric pressure. This is not the case for Mars which lacks an atmosphere due to its weak gravitional pull, water will therefore evaporate easily on mars than on earth