12. Penny can knit 4 rows of a sweater in 5
minutes. How many hours will it take her
to knit 300 rows?

Explanation:

Both new moon and lunar eclipse occur when the moon is in the same plane the sun and the earth. However, both are different because of the relative position of the moon in its orbit – relative to earth. In a new moon, the moon is in between the earth and the sun, while in a lunar eclipse, the earth us in between the moon and the sun.

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Answer:

A new moon and lunar eclipse occur when the moon is in the same plane as the earth and the sun. The moon is between the earth and the sun on a new moon. The earth is between the moon and the sun on a lunar eclipse.

Explanation:

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: Comparisons .

Answer:

c

Explanation:

the answer is comparisons

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 compound

Explanation:

A substance composed of two or more pure substances mixed together in variable proportions, with variable composition throughout, is called a heterogeneous mixture. These mixtures can have components that retain their individual chemical identities, which can often be physically separated.

When two or more pure substances are mixed together in variable proportions, without any chemical bonding between them, the resulting substance is known as a mixture. These mixtures where the composition is not consistent throughout are called heterogeneous mixtures. Examples include sand and water, or oil and water. Unlike a compound, where elements are in fixed proportions and chemically bonded, the substances in a mixture retain their individual chemical properties and can often be physically separated.

Mixtures stand in contrast to compounds, which are substances composed of two or more elements in fixed proportions and can only be separated into their constituent elements by chemical methods.

The concept of composition variables, such as the number of moles of each component, is crucial for describing the properties of mixtures. Air, with its variable amounts of nitrogen and oxygen, is an example of a mixture with each component retaining its characteristic properties.

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

Answer:

1. Viscosity describes how "thick" a liquid is. This is based on its resistance to flow. Viscosity is measured in 'poise' (written P)

2. Fluids can be described as having great, or little viscosity.

3. Tar, Glycerol, Sulfric Acids

4. Mercury, Blood, Dilute polyethylene oxides

(Can't answer #5-9 because I don't know what lab you are doing.)

Final answer:

Antacid tablets neutralizing stomach acid represents a chemical property, as it describes the substance's ability to undergo a chemical change and form different substances.

Explanation:

The statement among the given options that describes a chemical property is 'Antacid tablet’s neutralize stomach acid.' This statement describes the ability of a substance to undergo a specific chemical change. A chemical property involves a substance's ability to convert into a different substance, which is what antacid tablets do when they interact with stomach acid to produce salt and water, neutralizing the acid.

In contrast, the other statements describe physical properties: Iodine sublimating from a solid to a gas is a physical change because it changes state but does not become a new substance; helium being the lightest monatomic element describes its physical characteristic; and water freezing at 0°C is a physical change because it changes the state from liquid to solid without altering the chemical composition.

Answer: If you were asking for it to be balanced then its 10 C7H602 + 70 O2 = 70 CO2 + 301 H20

Explanation: i hope this helped you

Au₂S₃

Explanation:

Given compounds:

Gold(I) oxide = Au₂O

Gold(I)sulfide  = Au₂S

Gold(III) oxide = Au₂O₃

Gold(III)sulfide = Au₂S₃

Problem: compound with the least mass of Gold.

  To solve this problem, we simply find the mass percentage of gold in the given compounds.

Molar mass of Au₂O = 2(197) + 16  = 410g/mole

Molar mass of Au₂S = 2(197) + 32  = 426g/mole

Molar mass of Au₂O₃ = 2(197) + 3(16) = 442g/mole

Molar mass of Au₂S₃ = 2(197) + 3(32) = 490g/mole

The molar mass of gold in all the compound is 394g/mole

Mass percentage of gold in Au₂O  = [tex]\frac{394}{410}[/tex]  x  100 = 96.1%

Mass percentage of gold in Au₂S = [tex]\frac{394}{426}[/tex] x  100 = 92.5%

Mass percentage of gold in Au₂O₃ = [tex]\frac{394}{442}[/tex] x 100 = 89.1%

Mass percentage of gold in  Au₂S₃ = [tex]\frac{394}{490}[/tex] x 100 = 80.4%

Au₂S₃ is the least mass of gold in it

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Answer:

Explanation:

Given compounds:

Gold(I) oxide = Au₂O

Gold(I)sulfide  = Au₂S

Gold(III) oxide = Au₂O₃

Gold(III)sulfide = Au₂S₃

Problem: compound with the least mass of Gold.

 To solve this problem, we simply find the mass percentage of gold in the given compounds.

Molar mass of Au₂O = 2(197) + 16  = 410g/mole

Molar mass of Au₂S = 2(197) + 32  = 426g/mole

Molar mass of Au₂O₃ = 2(197) + 3(16) = 442g/mole

Molar mass of Au₂S₃ = 2(197) + 3(32) = 490g/mole

The molar mass of gold in all the compound is 394g/mole

Mass percentage of gold in Au₂O  =   x  100 = 96.1%

Mass percentage of gold in Au₂S =  x  100 = 92.5%

Mass percentage of gold in Au₂O₃ =  x 100 = 89.1%

Mass percentage of gold in  Au₂S₃ =  x 100 = 80.4%

Au₂S₃ is the least mass of gold in it

Answer:

Solid; denser

Explanation:

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.

Answer:

1. 1.34g

2. 1.19g

3. 0.49g

Explanation:Please see attachment for explanation

Answer:

$55.998

Explanation:

Given data:

Total yard in blanket = 1531 yard

Price of  2.00×10² m = $7.99

Total cost for blanket = ?

Solution:

As it is given in question that,

1 yard = 0.9144 m

1531 × 0.9144 m  = 1399.95 m

Total number of meters = 1399.95 m

Price of 2.00×10²(200) m = $7.99

Cost of one meter:

$7.99 / 200m = 1 m / x

x = $0.04

Now we will calculate the price of 1531 yard,

1399.95 m ×  $0.04 / 1m = $55.998

To make the blanket requiring 1531 yards of yarn using a speciality yarn sold in 200 meter hanks priced at $7.99 each, it would cost $55.93 after converting yards to meters and calculating the number of hanks needed.

The cost of making a blanket using the given yarn, we need to convert the required yarn from yards to meters to match the unit in which the speciality yarn is sold. Then, we can determine how many hanks of yarn are needed and calculate the total cost.

Conversion of Yards to Meters

Firstly, we convert the needed yarn for the blanket from yards to meters using the conversion factor 1 yard = 0.9144 meters.
1531 yards * 0.9144 meters/yard = 1400.0844 meters

Calculating the Number of Hanks Needed

Now, we calculate how many 2.00 x 102 meter hanks are required:

1400.0844 meters / (2.00 x 102 meters/hank) = 7 hanks (rounding up since you can't purchase a fraction of a hank)

Total Cost Calculation

Finally, the total cost is:

7 hanks * $7.99/hank = $55.93

Therefore, it would cost $55.93 to make the blanket out of this speciality yarn.

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

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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Tissue engineering is beneficial as stem cells automatically create a perfect organ shape and size, therefore, here option C is correct.

Tissue engineering is a biomedical engineering discipline that coordinates science with engineering  to make tissues or cell items outside the body or to utilize acquired information to more readily deal with the maintenance of tissues inside the body.

Numerous new cell treatments are being fostered that make difficulties for designing tissue capability.

The execution of cell treatments and unions in the facility requires the acknowledgment and goal of a few troublesome issues.

Tissue engineering is beneficial as, stem cells automatically create a perfect organ shape and size, hence option C is correct.

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Answer:

Sodium (NA)

Explanation:

Answer:

rubidium: rb

Explanation:

[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:

                     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:

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.

The number of reactants is the same as the number of products is the best statement that describes the conservation of mass in chemical equation

Explanation:

The term mole concept is used here to determine the number of hydrogen atoms in one mole. The number of 'H' atoms in one mole is 6.022 x 10²³ atoms. The correct option is D.

One mole of a substance is defined as that amount of it which contains as many particles or entities as there are atoms in exactly 12 g of Carbon - 12. The number of entities present in one mole of a species equals 6.022 x 10²³ . This value is called the Avogadro number.

The Avogadro number also called the Avogadro constant. It is represented as N₀. One gram atomic mass of any element contains Avogadro number of atoms. The number of atoms in 12 g of C-12 is also 6.022 x 10²³.

1 gram atom of hydrogen (i.e., 1.008 g) contains Avogadro number of atoms.

Thus the correct option is D.

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Final answer:

One mole of any substance contains Avogadro's number of particles. Hence, 1 mole of hydrogen atoms contains 6.02 x 10^23 atoms.

Explanation:

The question asks to calculate the number of hydrogen atoms in 1 mole. Avogadro's number, defined as the number of particles in 1 mole of a substance, is 6.022 x 1023 particles/mole. This principle is based on the standard that 1 mole of carbon-12 atoms has a mass of exactly 12.0 grams and contains 6.022 x 1023 carbon atoms. Given that 1 mole of any substance contains the same number of entities as there are in 1 mole of carbon-12, one mole of hydrogen atoms, regardless of its lesser mass compared to carbon-12, also contains exactly 6.022 x 1023 atoms. Therefore, the correct answer is D) 6.02 x 1023 atoms.

Answer:

C D A B

Explanation:

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.

Answer:

the second one I think

Explanation:

hope you get it correct!

Answer:

a

Explanation:

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:

a

Explanation:

Answer:

a

Explanation:

Answer: 1 mole Kr

Explanation: solution

83.80g Kr x 1mole Kr / 84 g Kr

= 0.997 or approximately 1 mole Kr