Type the correct answer in the box. Express your answer to two significant figures. An industrial vat contains 650 grams of solid lead(II) chloride formed from a reaction of 870 grams of lead(II) nitrate with excess hydrochloric acid. This is the equation of the reaction: 2HCl + Pb(NO3)2 → 2HNO3 + PbCl2. What is the percent yield of lead(II) chloride?

Answer:

4.87g

Explanation:

Step 1:

Data obtained from the question. This includes the following:

Mass of solution = 0.35kg

Molality = 0.238 m

Mass of NaCl =..?

Step 2:

Determination of the number of mole of NaCl in the solution.

Molality of a solution is simply defined as the mole of solute per unit kg of the solvent. It is given as:

Molality = mol of solute /mass of solvent (kg)

With the above formula, we calculate the mole of NaCl present in the solution as follow:

Molality = mol of solute /mass of solvent (kg)

0.238 = mol of NaCl /0.35

Cross multiply

mol of NaCl = 0.238 x 0.35

mol of NaCl = 0.0833 mol

Step 3:

Determination of the mass of NaCl in 0.0833 mol of NaCl.

This is illustrated below:

Number of mole NaCl = 0.0833 mol

Molar Mass of NaCl = 23 + 35.5 = 58.5g/mol

Mass of NaCl =..?

Mass = number of mole x molar Mass

Mass of NaCl = 0.0833 x 58.5

Mass of NaCl = 4.87g

Therefore, 4.87g of NaCl is contained in the solution.

Answer:

B.) A new substance is not formed

Explanation:

hope this helps

Ice melting is not a chemical change because a  new substance is not formed.

Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.

There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

There are three types of chemical changes:

1) inorganic changes

2)organic changes

3) biochemical changes

During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

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Answer:

CH2O

Explanation:

Pretend you have a 100 gram sample.

39.99 g C * (1 mol/12.01 g) = 3.33 moles C

53.28 g O * (1 mol/16 g) = 3.33 moles O

6.73 g H * (1 mol/ 1.008 g) = 6.676 moles H

You can see from this data that there are double the number of moles of H compared to the moles of C and O.

To find the empirical formula, you divide all the moles by the least number of moles. In this case, the least number of moles is 3.33. So for carbon and oxygen, divide 3.33 by 3.33... this equals 1. For H, divide 6.676 by 3.33... this is about equal to 2. Therefore, the empirical formula is CH2O. :)

Hope this was helpful!

Answer: [tex]COH_2[/tex]

Explanation:

39.99% C

53.28% O

6.73% H

First step:

Change % to g

39.99g C

53.28g O

6.73g H

Second step:

Calculate the number of g/mol using atomic mass.

[tex]39.99gC(\frac{1mol}{12g} )=3.332mol[/tex]

[tex]53.28gO(\frac{1mol}{16g})=3.330mol[/tex]

[tex]6.73gH(\frac{1mol}{1g} )=6.73mol[/tex]

Third step:

Determine the smallest number of moles and divide each compound by it. When you get the result, simply put the whole number, not decimals.

[tex]C=\frac{3.332mol}{3.330mol}=1[/tex]

[tex]O=\frac{3.330mol}{3.330mol} =1[/tex]

[tex]H=\frac{6.73mol}{3.330mol}=2[/tex]

Fourth step:

Rewrite those number under the compounds.

This empirical formula should be: [tex]COH_2[/tex]

Answer:

Over 700,000 lives are taken by the AIDs virus every year. Hepatitis C claims the lives of over 200,000 people each year and haemorrhagic fevers caused by viruses such as Ebola have resulted in over 20,000 deaths.

Explanation:

Answer: c

Explanation: it is the temperature at which Fahrenheit and Celsius read the same

It's the temperature at which Fahrenheit and Celsius thermometers read the same exists significant about the temperature -40°C.

One of the most pervasive and significant physical elements in an organism's environment is temperature. It is a gauge for the typical speed of atoms and molecules moving at random; the higher the temperature, the faster the motion.

Because temperature affects the physical state of water, it has the greatest impact on how organisms are distributed. Most organisms cannot survive in environments where the temperature is consistently below 0°C or above 45°C.

Since there are 100 units between the freezing (0°C) and boiling (100°C) points of water, the Celsius scale is a centigrade scale. The majority of the world uses this temperature scale, which is also the recognized unit of measurement in science.

It's the temperature at which Fahrenheit and Celsius thermometers read the same exists significant about the temperature -40°C.

Therefore, the correct answer is option C. It's the temperature at which Fahrenheit and Celsius thermometers read the same.

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Answer:

true

Explanation:

The A horizon, known as the topsoil, is essential for plant production due to its rich organic content, while the B horizon, or subsoil, is denser and stores inorganic nutrients.

Topsoil is considered the A horizon, consisting of partially decayed organic matter that enhances soil moisture retention, while the Subsoil is the B horizon, a dense layer with inorganic nutrients accumulation.

In understanding soil composition and structure, it's crucial to identify the different layers or horizons that make up the soil profile. The topsoil is referred to as the A horizon, which is the layer where the soil possesses a mixture of organic material and inorganic products of weathering. This horizon is typically dark due to the presence of organic matter, making it highly crucial for plant production as it retains water and facilitates oxygen diffusion necessary for root respiration. Below the topsoil lies the subsoil, known as the B horizon. This layer accumulates mostly fine material that has been translocated downwards from the A horizon, making it denser. The subsoil is critical for the storage of inorganic nutrients but is lighter in color and has fewer organic materials compared to the topsoil.

Answer:

A

Explanation:

Answer:

es la A

Explanation:

Answer:

A system is a group of related parts that work together as a whole.

Explanation:

edmentum.

A system is a set of interacting elements regarded as a distinctive entity for the purpose of study or observation. It can be physical like planets in a solar system, abstract like the systems operating in a computer, or organic like our nervous system.

A system can be defined as a set of elements that interact with each other and can be considered as a single entity, often for the purpose of study or analysis. This grouping can be physical, such as planets in a solar system, or conceptual, like the motor and visual systems in the human body. Systems, whether isolated, closed, or open, abide by certain laws, including conservation laws. Isolated and closed systems have minimal interactions with their environment, while open systems can exchange energy and/or matter with their surroundings.

Examples of systems can be seen everywhere, from how your computer operates as a system, to natural systems such as your nervous system processing sensory information and controlling your body's functions.

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Answer:

The correct answer is option A, that is, mitosis only has one cell division set.

Explanation:

The two kinds of nuclear division that takes place at the time of cell differentiation are meiosis and mitosis. In the process of mitosis, the cells of the body get divide, while in meiosis the sex cells are differentiated.  

While going through the process of mitosis, the cell divides only one time, on the other hand, during meiosis a cell divides two times. After going through mitosis production of two diploid daughter cells takes place, while after going through meiosis generation of four haploid daughter cells takes place. Thus, it is clear from the diagram that the process of meiosis is taking place, as the formation of four haploid cells is taking place as the cell is dividing two times.  

Answer:

16.48mL

Explanation:

The following data were obtained from the question:

Initial pressure (P1) = 1 atm

Initial temperature (T1) = 0°C = 0°C + 273 = 273K

Initial volume (V1) = 30mL

Final temperature (T2) = 27°C = 27°C + 273 = 300K

Final pressure (P2) = 2atm

Final volume (V2) =..?

Applying the general gas equation, the final volume of the gas can be obtained as follow:

P1V1/T1 = P2V2/T2

1 x 30/273 = 2 x V2/300

Cross multiply to express in linear form

273 x 2 x V2 = 30 x 300

Divide both side by 273 x 2

V2 = (30 x 300)/(273 x 2)

V2 = 16.48mL

Therefore, the new volume of the gas is 16.48mL

The volume of a sample of gas that starts at 1.00 atm, 0.00 degrees celsius, and 30.0 mL is 16.48mL. Details about volume can be found below..

The volume of an ideal gas can be calculated by using the following formula:

P1V1/T1 = P2V2/T2

Where;

1 × 30/273 = 2 × V2/300

0.109 = 2V2/300

32.97 = 2V2

V2 = 16.48mL

Therefore, the volume of a sample of gas that starts at 1.00 atm, 0.00 degrees celsius, and 30.0 mL is 16.48mL.

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Answer:

I. hurricanes

Explanation:

Answer:

C

Explanation:

Reptiles generally pose some sort of natural bewilderment to most people.

Answer:

New volume of the balloon at sea level (V1) = 4.25 L

Explanation:

Given:

Present volume (V) = 5 L

Present pressure (P) = 0.85 atm

Pressure at sea level (P1) = 1 atm

Find:

New volume of the balloon at sea level (V1) = ?

Computation:

According to  Boyles law:

⇒ P × V = P1 × V1

⇒ 0.85 × 5 = 1 × V1

⇒ 4.25 L = V1

New volume of the balloon at sea level (V1) = 4.25 L

Answer: C. Rectum

Explanation:

Since 4.184 Joules equals one calorie, simply we need to make a cross multiply equation.

4.184J/1cal=x J/230000cal

Then we can multiply the crosses and set them equal to each other. 4.184(230000)=1x

962320=x

The healthy breakfast supplies 962320 joules worth of food.

Answer:

1 and 2 only

Explanation: These will make a bad impact on water.

Answer:

%yield of NH₃ = 30%

Explanation:

Actual yield of NH₃ = 40.8g

Theoretical yield = ?

Equation of reaction

N₂ + 3H₂ → 2NH₃

Molar mass of NH₃ = 17g/mol

Molarmass of N = 14.00

2 molecules of N = 2 * 14.00 = 28g/mol

Number of moles = mass / molar mass

Mass = number of moles * molar mass

Mass = 1 * 28.00 = 28g of N₂ (the number of moles of N₂ from the equation is 1).

From the equation of reaction,

28g of N₂ produce (2 * 17)g of NH₃

28g of N₂ = 34g of NH₃

112g of N₂ = x g of NH₃

X = (112 * 34) / 28

X = 136g of NH₃

Theoretical yield = 136g of NH₃

% yield = (actual yield / theoretical yield) * 100

% yield = (40.8 / 136) * 100

% yield = 0.3 * 100

% yield = 30%

Answer:

Uranium

Explanation:

Answer:

Uranium

Explanation:

Answer:

K-47 undergoes beta decay

Hg-190 undergoes electron capture or alpha decay

Th-232 undergoes alpha decay

Na-20 undergoes positron emission

I-137 undergoes beta decay

Explanation:

Stability of a nucleus is decided by the neutron /proton (n/p) ratio. For lower elements of atomic number 1-20, n/p=1. Elements with higher atomic numbers tend to have a slight excess of neutrons to reduce the repulsive forces between the protons.

Beta emission decreases the n/p ratio, positron emission increases the n/p ratio, electron capture increases the n/p ratio and alpha decay increases the n/p ratio.

Note that a nucleus may undergo several decay processes before stable nucleus (nuclei) is/are formed.

The decay mode of radioactive isotopes is primarily determined by the atomic number (Z) and the neutron-proton (n/p) ratio. For example, K-47 and Hg-190, with high n/p ratios, would decay through β emission. Th-232, having Z≥84 and a high n/p ratio would undergo α emission. Na-20, being a light nucleus with a low n/p ratio would do positron emission, and I-137 with high n/p ratio would do β emission.

Based on our understanding of nuclear stability and decay, radioactive isotopes decay in a way that brings them closer to a state of stability. They do this by adjusting their neutron to proton ratios (n/p) through various forms of decay. The mode of decay depends largely on the Z number (atomic number) and the n/p ratio.

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Answer:

drought

Explanation:

In an ecosystem, some plant seeds are adapted to sprout with a limited amount of water. They are adapted to drought.

Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.

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Answer:

1. 44.11 g

2. 36.03 g

3. 8.08 g

4. 81.7%

5. 18.3%

Explanation:

1. 12.01+12.01+12.01+1.01+1.01+1.01+1.01+1.01+1.01+1.01+1.01=44.11

2. 12.01×3= 36.03

3. 1.01×8= 8.08

4.(36.03/44.11)×100= 81.7%

5. (8.08/44.11)×100= 18.3%

The molar mass of C3H8 is 44.094 g/mol. The carbon percent composition is 81.72% and the hydrogen percent composition is 18.28%.

The molar mass of C3H8 (propane) can be calculated by adding up the atomic masses of the atoms in the molecule. Carbon has a molar mass of 12.01 g/mol, and there are 3 carbon atoms in C3H8, so the total molar mass for carbon atoms is 12.01 g/mol x 3 = 36.03 g/mol. Hydrogen has a molar mass of 1.008 g/mol, and there are 8 hydrogen atoms in C3H8, so the total molar mass for hydrogen atoms is 1.008 g/mol x 8 = 8.064 g/mol.

The percent composition can be calculated by dividing the molar mass for each element by the total molar mass of C3H8. The carbon percent composition is (36.03 g/mol / 44.094 g/mol) x 100% = 81.72%. The hydrogen percent composition is (8.064 g/mol / 44.094 g/mol) x 100% = 18.28%.

Answer:

A.)

Explanation:

From the balanced equation, it is clear that the mole ratio of the hydrazine to hydrogen peroxide is 1 :2 and that of hydrazine to water is

1 :4.

The mole ratio is the ratio between the number of moles of a reactant to the number of moles of another reactant.

The balanced chemical equation for the reaction is:

N2H4 + 2H2O2 → N2 + 4H2O

From the equation, the mole ratio of hydrazine (N2H4) to hydrogen peroxide (H2O2) is 1:2, which means that for every one mole of hydrazine used, two moles of hydrogen peroxide are used.

Similarly, the mole ratio of hydrazine (N2H4) to water (H2O) is 1:4, which means that for every one mole of hydrazine used, four moles of water are produced.

Therefore, the correct option is 1:2 and 1:4.

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Answer:

0.625 kg

Explanation:

Since 90.6 is 3 half-lives from 30.2 (90.6/30.2 = 3) , divide the initial mass of the sample by 2, and divide that quotient by 2, and divide THAT quotient by 2 to determine how much remains after 3 half-lives.

The mass will remain at 1.6 kg.

Mass after t years:

The mass of the elements after t years is given by the following equation:

M(t) = M(0)(1-r)[tex]^{t}[/tex]

The half-life of Cs-137 is 30.2 years.

This means that:

M (30.2) = 0.5 M (0)

M (t) = M (0)(0.9773)[tex]^{t}[/tex]

This is M(151), with M(0) = 100.

Then,

M(90.6) = 5(0.9773)[tex]^{90.6}[/tex]

= 5*0.24

= 1.2 kg

Cesium-137 emits beta particles as it decays to the barium isotope, Ba-137m.

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Answer:

0.498 kg

Explanation:

Answer:

The first answer is 498

The second answer is 0.498

Explanation:

Answer:

9.85g/cm³

Explanation:

Mass = 19.7g

Volume = 2cm³

Density (ρ) = mass (m) of a substance / volume (v) it occupies

ρ = mass / volume

ρ = 19.7 / 2

ρ = 9.85g/cm³

Answer:

9.85g/cm3

Explanation:

The following data were obtained from the question:

Mass = 19.7g

Volume = 2cm3

Density =..?

Density of a substance is simply defined as the mass per unit volume. It is represented mathematically by:

Density = Mass /volume

With the above formula we can find the density of the acrylic as follow:

Density = 19.7g/2cm3

Density = 9.85g/cm3

Answer:

Yes

Explanation:

On top of Mt. Yale in Colorado (elevation 14,202 feet), you step on a scale and weigh 183 pounds, using the same scale in New Orleans (elevation 4 feet) you would weigh more than on top of Mt. Yale.

Hence, option A is correct.

Pound, unit of avoirdupois weight, equal to 16 ounces, 7,000 grains, or 0.45359237 kg, and of troy and apothecaries' weight, equal to 12 ounces, 5,760 grains, or 0.3732417216 kg. The Roman ancestor of the modern pound, the libra, is the source of the abbreviation lb.

183 is to 14202 as x is to 4

183/14202 = x/4

14202x = 183(4)

x = 183(4)/14202

x = 0.0515 pounds

Hence, option A is correct.

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Answer:

your answer

Explanation: