Magnesium has 3 naturally occurring isotopes: 24 Mg (23.985 amu) with 78.99% abundance,
25 Mg (24.986 amu) with 10.00% abundance, and a third with 11.01% abundance.
Look up the atomic weight of magnesium, and then calculate the mass of the third isotope.

Answer:

0.00125 liters of product

Explanation:

So the question it tell you that 0.25 % from 0.5 liters is pure product.

So we calculate the volume of pure product:

volume = (0.25 / 100) × 0.5 = 0.00125 liters

Now to produce the solution over 0.00125 liters of pure product you add (most likely) water until you reach a volume of 0.5 liters.

Final answer:

OPTION B.

Dalton's atomic theory highlighted that atoms are the smallest indivisible units of matter and that they combine in whole number ratios to form compounds.

Explanation:

One main point of Dalton's atomic theory is that atoms made up the smallest form of matter. Dalton proposed that all matter is composed of these minute, indivisible particles, which he referred to as atoms, and these atoms cannot be subdivided, created, or destroyed. This concept also suggested that atoms of a given element are identical in size, mass, and other properties, whilst atoms of different elements differ. Additionally, Dalton's theory asserted that atoms of different elements can combine in whole number ratios to form chemical compounds and that during chemical reactions, atoms are rearranged but neither created nor destroyed.

Answer:

The unknown base should be KOH whose molar mass is 56 g per mol (Answer)

Explanation:

Molarity = moles /(Volume in liters)  

So,  

Moles = Molarity [tex]\times[/tex] Volume

[tex]\\$=0.219 M \times 289 m L$\\\\$=0.219 \frac{m o l}{L} \times 0.289 L$\\\\$=0.063291 \mathrm{mol}$[/tex]

Molar mass = mass/moles

[tex]\\\\$=\frac{3.50 \mathrm{g}}{0.063291 \mathrm{mol}}=55.3 \mathrm{g}$ per mole[/tex]

The unknown base should be KOH whose molar mass is 56 g per mol (Answer)

The number of atoms in 1.60 moles of selenium is approximately 9.64 x 10^23 atoms.

In order to determine the number of atoms in 1.60 moles of selenium, we need to use Avogadro's number. Avogadro's number is 6.022 x 10^23 atoms per mole.

So, for 1.60 moles of selenium, we can calculate the number of atoms as:

Number of atoms = 1.60 moles x 6.022 x 10^23 atoms/mole

Number of atoms = 9.6352 x 10^23 atoms

Therefore, there are approximately 9.64 x 10^23 atoms in 1.60 moles of selenium.

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To determine the empirical formula for the compound with given masses of Ba and Br, convert the masses to moles and find the ratio of the moles. In this case, the empirical formula is BaBr2.

To calculate the empirical formula for each compound, we need to determine the ratio of the elements in the compound using their masses.

Given the masses of Ba and Br, we can convert them to moles using their respective molar masses.

The molar mass of Ba is 137.33 g/mol, and the molar mass of Br is 79.90 g/mol.

Using these values, we find that there are 0.0195 moles of Ba and 0.0390 moles of Br in the given sample.

To find the empirical formula, we need to divide the moles of each element by the smallest number of moles obtained. In this case, the smallest number of moles is 0.0195.

Dividing the moles of Ba and Br by 0.0195 gives us approximately 1 mole of Ba and 2 moles of Br.

Therefore, the empirical formula for the compound is BaBr2.

The moss leaf cells contain cell wall, nucleus, chloroplasts, and cell membrane.

The moss leaf cells contain the following cell structures:

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Moss leaf cells contain a cell wall, a nucleus, chloroplasts, mitochondria, and a cell membrane. The cell wall provides structure, the nucleus acts as the command center, chloroplasts facilitate photosynthesis, mitochondria produce energy, and the cell membrane controls substance movement.

Moss leaf cells contain several common structures seen in plant cells. They have a cell wall, which is primarily composed of cellulose and serves functions such as protection, providing structural support, and giving shape to the cells.

These cells also contain a nucleus, which is the control center of the cell. There are chloroplasts present in moss leaf cells; this is where photosynthesis takes place, allowing the plant to convert sunlight into energy. Moss leaf cells also have mitochondria, which are the powerhouses of cells as they are responsible for producing energy in the form of ATP. Finally, these cells have a cell membrane, which is the semipermeable membrane surrounding the cytoplasm of the cell, controlling the movement of substances in and out of the cell.

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Answer:

0.00576

Explanation:

To round 0.005758 to three significant figures, we get 0.00576. We only consider the first non-zero digit and the two digits to its right for this purpose.

To round the number 0.005758 to three significant figures, we first locate the first non-zero digit from the left, which is 5. We then count two more digits to its right, thus including 7 and 5. We denote these as the significant figures. The next digit after these is 8, since it is more than 5, it rounds the prior digit (5) up by one. Therefore, the number 0.005758 rounded to three significant figures is 0.00576.

Leading zeros are not considered as significant figures. The significant figures in a number are digits that carry meaning contributing to its precision. This includes all non-zero numbers, zeros between significant figures, and any trailing zeros if the number is a decimal.

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If the mass of the cup alone is 15.92 g, the volume of liquid Z in the cup will be 39.11 mL.

Volume is a measure of the amount of space that matter occupies. Matter is defined as a physical substance that occupies space and has a mass.

Volume of liquid Z = (Total mass - Cup mass) / Density of liquid Z

= (50.7 g - 15.92 g) / 0.9237 g/mL

= 34.78 g / 0.9237 g/mL

= 39.11 mL.

Therefore, if the mass of the cup alone is 15.92 g, the volume of liquid Z in the cup will be 39.11 mL.

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Answer:

C. a spectrum of many different colors of light.

Explanation:

White light is made up of all the colors and all wavelengths.

Answer:

c

Explanation:

Answer:

123lb

Explanation:

lb= 2.2046 kg

56×2.2046= 123lb

A person with a mass of 56 kg weighs approximately 123.46 pounds.

The conversion uses the factor that 1 kilogram is approximately 2.20462 pounds. Mass is the amount of matter, while weight is the gravitational force on that matter.

To convert a person's mass from kilograms to pounds, you can use the conversion factor that 1 kilogram is approximately equivalent to 2.20462 pounds.

Conversion Calculation:

Given a mass of 56 kg, you can calculate the weight in pounds as follows:

Weight in pounds = Mass in kilograms × Conversion factor

Weight in pounds = 56 kg × 2.20462 lbs/kg

Weight in pounds ≈ 123.46 lbs

So, a person with a mass of 56 kg weighs approximately 123.46 pounds.

Understanding Mass and Weight:

Note that mass is a measure of the amount of matter in an object, while weight is the force exerted by gravity on that mass. In the US customary units, weight can be expressed in pounds, where 1 lb is equivalent to a mass of 0.4536 kg.

Answer:

The volume is 3.96 dL

Explanation:

Step 1: Convert ml to dl

1Liter = 1000ml = 10³ ml

1Liter = 10 dl

⇒ 1 Liter has 1000ml or 10 dl

⇒ The ratio can be written as : 10dl/ 1000ml = 1 dl / 100ml

Step 2: Convert cm³ =

⇒ 1cm³ is equal to 1 ml.

Step 3:  Calculate volume

⇒ We use the formule of density here, which is : Density (p) = mass (g) / volume( cm³)

⇒ 7.86 g/ cm³  = 3110 grams / Volume ( cm³)

⇒Volume = 3110 grams / 7.86g/cm³ = 395.67 cm³

395.67 cm³ = 395.67 ml = 0.39567 L  = 3.96 dL

3.96 dL is reported to three significant digits due to the precision reported for the density.

Answer:

N2 + O2 --->  2NO

Explanation:

There has to be the same amount of elements on both sides of the equation and it's the rules of chemistry that you cannot add subscripts to the elements because that just changes the whole compound so you must always add coefficients. (The 2 distributes to both elements)

Final answer:

The balanced equation for the reaction between molecular nitrogen (N2) and oxygen (O2) to form nitrogen monoxide (NO) is N2(g) + O2(g) → 2 NO(g). Adding more O2 to a system at equilibrium will shift it to form more NO.

Explanation:

To balance the given equation N2 + O2 → NO, one must ensure that there are equal numbers of each type of atom on both sides of the equation. Starting with nitrogen, we have one N2 molecule, which contains 2 N atoms. On the right side, there is one NO molecule, which contains only 1 N atom, so we can place a coefficient of 2 in front of NO to balance nitrogen. Now we have 2 atoms of nitrogen on both sides. Initially, we have one O2 molecule with 2 O atoms and only one O atom in each NO molecule. After balancing nitrogen, we have two NO molecules, bringing the number of O atoms to two, which balances the oxygen atoms as well. So the balanced equation is N2(g) + O2(g) = 2 NO(g).

If more O2 is added to this system at equilibrium, according to Le Chatelier's Principle, the system would adjust to counteract this change by forming more NO, thus consuming some of the added O2 and potentially shifting the equilibrium position.

Answer:

The answer to your question is letter D.

Explanation:

Bohr tells us that the electrons which have a negative charge clicle the orbits in specific nucleus, so the right answer is letter D.

Letter C is not possible because the electrons are in orbits circling the nucleus where the protons are.

Letter B is not correct because electrons are distributed in orbits but the amount of electrons in one orbit is different to the other one.

The electrons found around the nucleus in specific orbit in Bohr's atomic model.

So, option D is correct one.

This model explained about position of electron and their energy levels.

According to  Bohr's atomic model the electron revolve around the nucleus in particular orbit or shell.

Rutherford's model described about nucleus which is surrounded by the electrons which is negatively charged.

To learn more about Bohr's atomic model here.

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Answer:

Explanation:

To separate the a mixture of chalk and potassium chloride, we must not that chalk is calcium carbonate compound, CaCO₃.

Calcium carbonate has low solubility in water. KCl is readily soluble in water and it is also an ionic compound.

To separate a mixture of compounds with various solubility, we can carryout dissolution, filtration and evaporation.

We first pour pure water into the mixture. Water will dissolve the potassium chloride readily.

Then using a filter paper we filter out the suspended chalk particles. Leave the filtrate to then dry and collect it.

The solution filtered should be evaporated to dryness. This will leave the KCl behind from the solution.

Answer:Shape and volume

Explanation:

Answer:

1. Color Change

2. Change in temperature

3. Noticiable Odor

4. Formation of bubbles

A chemical change, usually irreversible, results in the formation of new substances, the release or absorption of energy, and sometimes the production of gases or solids. Indicators of a chemical change include changes in color, production of a gas, formation of a precipitate, and changes in temperature.

A chemical change is a process that results in the transformation of one set of chemical substances to another. During this type of change, the atoms in the reactants rearrange to form one or more different substances, and this is usually an irreversible process. Some common results of a chemical change can include the formation of new substances, the release or absorption of energy, and the production of gases or solid materials.

Four indicators of a chemical change are:

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Final answer:

To calculate the average atomic mass of an element with three naturally occurring isotopes, multiply the mass of each isotope by its natural abundance in decimal form, and then sum the results.

Explanation:

To calculate the average atomic mass of an element with three naturally occurring isotopes, we need to multiply the mass of each isotope by its natural abundance in decimal form, and then sum the results. Let's use an example to illustrate this calculation. Suppose an element has three isotopes: X-1 with a mass of 1.000 amu and a natural abundance of 40%, X-2 with a mass of 2.000 amu and a natural abundance of 50%, and X-3 with a mass of 3.000 amu and a natural abundance of 10%. We can calculate the average atomic mass as follows:

(1.000 amu * 0.40) + (2.000 amu * 0.50) + (3.000 amu * 0.10) = 0.400 amu + 1.000 amu + 0.300 amu = 1.700 amu

Answer:

234 KJ ≡ 55.887 Kcal

Explanation:

∴ J ≡ Kg/m².s² ≡ N.m = 0.2389 cal

∴ cal = 4.187 J

⇒ 234 KJ * ( 1000 J / KJ ) * ( cal / 4.187 J ) * ( Kcal / 1000 cal ) = 55.887 Kcal

Answer : The correct number of significant figures in scientific notation is [tex]9.791\times 10^2\text{ kilocalorie}[/tex]

Explanation :

The conversion used from kilojoules (kJ) to kilocalories (kcal) is:

1 Joule = 4.184 Calorie

or,

1 kilojoule = 4.184 kilocalorie

As we are given that the energy 234 kJ. Now we have to convert it into kcal.

As, [tex]1\text{ kilojoule}=4.184\text{ kilocalorie}[/tex]

So, [tex]234\text{ kilojoule}=\frac{234\text{ kilojoule}}{1\text{ kilojoule}}\times 4.184\text{ kilocalorie}=9.791\times 10^2\text{ kilocalorie}[/tex]

Therefore, the correct number of significant figures in scientific notation is [tex]9.791\times 10^2\text{ kilocalorie}[/tex]

Answer:

Paper  

Explanation:

Paper chromatography is a method of separating mixtures of coloured substances into their components.

It uses a stationary phase and a mobile phase.

A tiny drop of a solution of the mixture is applied to the paper, which is suspended in a solvent.

The solvent flows through the paper and carries the components of the mixture with it.

Different components travel at different rates, so the mixture separates into different coloured spots as the solvent front moves up the paper.

The solvent moves up the paper, so it is the mobile phase.

The paper does not move, so it is the stationary phase.

PV = nRT

where P is the pressure,

V is the volume,

n is the moles of gas,

R is the gas constant,

and T is the temperature.

We must relate this equation to a sample of gas at two different volumes however. Looking at the equation, we can relate the change in volume by:

P1V1 = P2V2

where P1 is the initial pressure,

V1 is the initial volume,

P2 is the final pressure,

and V2 is the final volume.

Looking at this relationship, pressure and volume have an indirect relationship; when one goes up, the other goes down. In that case, we can use this equation to solve for the new pressure.

P1V1 = P2V2

(759 mm Hg)(1.04 L) = P2(2.24 L)

P2 = 352 mm Hg (rounded to three significant figures)

To find the pressure in the expanded gas sample, you can use Boyle's Law: P1V1 = P2V2. Plugging in the values, the pressure in the expanded gas sample is 353.03 mm Hg.

To find the pressure in the expanded gas sample, we can use Boyle's Law, which states that the pressure and volume of a gas are inversely proportional at constant temperature. This means that as the volume increases, the pressure decreases, and vice versa.

Using the formula P1V1 = P2V2 (where P1 and V1 are the initial pressure and volume, and P2 and V2 are the final pressure and volume), we can solve for P2:

P2 = P1V1/V2

Plugging in the given values, P1 = 759 mm Hg, V1 = 1.04 L, and V2 = 2.24 L:

P2 = (759 mm Hg)(1.04 L)/(2.24 L) = 353.03 mm Hg

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Answer:

Explanation:

Thinking like a scientist can help me make daily rational decisions between my wants. In that the way I see want would be ultimately to satisfy the most pressing of needs. This is where the open minded nature of scientist will come in. A scientist would rather chose to buy a new bike than going on expensive dates in order to cut and save travel time.

Thinking like a scientist can help me save cost on actually going out there to buy a cake or making one myself. This is the creative aspect of being a scientist. Why have the ingredient and the skill and I will still choose to go out there buy a cake?

A scientist reads a magazine with all mind seeking to establish the bias that might be laden in an edition. This will help him to rationale between different information presented on the pages of the paper. He/she would question the information source and not believe the story completely.

Answer:

From an object with a high temperature to an object with a lower temperature.

Explanation:

Answer:

the red one in each pair

Explanation:

see the picture2

Answer:

Here's what I find.

Explanation:

8. Electron affinity

The atom that is closer to having a complete valence shell (is further to the right in the Periodic Table) will have the greater electron density. The correct answers are:

(a) Br  

(b) Si

(c) Cl

9. Atomic radius

(a) Ca.  Ca is one period closer to the bottom of the Periodic Table. It has one more electron shell than Mg, so its valence electrons are further from the nucleus.

(b) Al. P is two atoms to the right of Al, so it has two more protons in the nucleus. Its valence electrons are held more tightly, so it is the smaller atom.

(c) F⁻. An anion is always larger than its neutral atom the added electron increases electron repulsions. The electrons move further out so they can reduce these repulsions.

10. Ionization energy

(a) He.  He is  a smaller atom, so its electrons are closer to the nucleus and more difficult to remove.

(b) Mg. Mg is to the right of Na and has a filled 3s subshell. Both factors make it more difficult to remove an electron.

(c) Ca²⁺. Once you have removed the two valence electrons from an atom of Ca, you have exposed its argon-like inner core. It takes more energy to remove an electron from a completed shell.

Answer:

6.06miles

Explanation:

Given parameters:

Speed of the car = 39km/hr

Time = 15minutes

Unkown:

Distance in miles

Solution:

  Speed is the change in distance with time.

             Speed = [tex]\frac{Distance }{Time}[/tex]

We need to express our parameters in the same workable units. So we should convert the given time to hour.

          60min = 1hr

          15 min = 0.25hr

   Therefore:

           Distance = speed x time = 39km/hr x 0.25hr = 9.75km

Now convert km to miles

                      1.609km = 1mile

                        9.75km =  [tex]\frac{9.75 }{1.609}[/tex] , 6.06miles

Answer:

Explanation:

A cold front is a transition zone from warm air masses to cold air masses. We use weather elements to identify cold fronts.

Answer:

24249.65 mol

Explanation:

n=MM × m

n= 39.95 ×607

n=24249.65

Answer:

Protons: 79

Electrons: 78

Explanation:

1. The number of protons is the atomic number (The atomic number for Au on the periodic table is 79)

2. Since the charge is +1 (positive) it means that there's one more proton than electrons. So, 79-1 = 78 electrons