Question 1 (1 point)
What is the term that scientists use when comparing the properties of solids, liquids and gases?

Q.No. 1:

            You have 20.0 g of CaCO₃. You decompose it by heat, and weigh the calcium oxide that  remains. You have 10.3 grams. What is the % yield?

Answer:

               %age Yield = 92.37 %

Solution:

               The balance chemical equation for given decomposition reaction is;

                                           CaCO₃ → CaO + CO₂

Step 1: Calculate Moles of CaCO₃:

                Moles  =  Mass / M.Mass

                Moles  =  20.0 g / 100.08 g/mol

                Moles  =  0.199 moles of CaCO₃

Step 2: Calculate theoretical amount of CaO produced;

According to equation,

              1 moles of CaCO₃ produced  =  1 mole of CaO

So,

           0.199 moles of CaCO₃ will produce  =  X moles of CaO

Solving for X,

                     X  =  0.199 mol × 1 mol / 1 mol

                     X  =  0.199 mol of CaO

Also,

         Mass  =  Moles × M.Mass

         Mass  =  0.199 mol × 56.07 g/mol

         Mass  =  11.15 g of CaO

Step 3: Calculate %age Yield as;

         %age Yield  =  Actual Yield / Theoretical Yield × 100

         %age Yield  =  10.3 g / 11.15 g × 100

         %age Yield = 92.37 %

___________________________________________

Q.No. 2:

            A student makes sodium chloride by buming 2.3 grams of sodium in chlorine  gas. If the yield is 90%, how much sodium chloride is made?

Answer:

               Actual Yield =  5.785 g of NaCl

Solution:

               The balance chemical equation for given decomposition reaction is;

                                           2 Na + Cl₂ → 2 NaCl

Step 1: Calculate Moles of Na:

                Moles  =  Mass / M.Mass

                Moles  =  2.3 g / 23 g/mol

                Moles  =  0.10 moles of Na

Step 2: Calculate theoretical amount of NaCl produced;

According to equation,

              2 moles of Na produced  =  2 moles of NaCl

So,

           0.10 moles of Na will produce  =  X moles of NaCl

Solving for X,

                     X  =  0.10 mol × 2 mol / 2 mol

                     X  =  0.10 mol of NaCl

Also,

         Mass  =  Moles × M.Mass

         Mass  =  0.10 mol × 58.44 g/mol

         Mass  =  5.844 g of NaCl

Step 3: Calculate Actual Yield as;

         %age Yield  =  Actual Yield / Theoretical Yield × 100

Or,

         Actual Yield  =  %age Yield × Theoretical Yield ÷ 100

         Actual Yield  =  99 × 5.844 g ÷ 100

         Actual Yield =  5.785 g of NaCl

___________________________________________

Q.No. 3:

            For the chemical reaction Mg(s) + 2 HCl (aq) → H₂ (g) + MgCl₂ (aq) calculate the  % yield if 100 grams of magnesium react with excess HCl to produce 310 grams of MgCl₂.

Answer:

               %age Yield = 79.13 %

Solution:

               The balance chemical equation for given decomposition reaction is;

                                           Mg + 2 HCl → MgCl₂ + H₂

Step 1: Calculate Moles of Mg:

                Moles  =  Mass / M.Mass

                Moles  =  100 g / 24.30 g/mol

                Moles  =  4.11 moles of Mg

Step 2: Calculate theoretical amount of MgCl₂ produced;

According to equation,

              1 mole of Mg produced  =  1 mole of MgCl₂

So,

           4.11 moles of Mg will produce  =  X moles of MgCl₂

Solving for X,

                     X  =  4.11 mol × 1 mol / 1 mol

                     X  =  4.11 mol of MgCl₂

Also,

         Mass  =  Moles × M.Mass

         Mass  =  4.11 mol × 95.21 g/mol

         Mass  =  391.73 g of MgCl₂

Step 3: Calculate %age Yield as;

         %age Yield  =  Actual Yield / Theoretical Yield × 100

         %age Yield  =  310.0 g / 391.73 g × 100

         %age Yield = 79.13 %

The balanced reaction is 3 Ca ( s ) + N 2 ( g )  →  Ca 3 N 2 ( s ).

Explanation:

A chemical equation is said to be balanced when the total number of atoms present on the reactants side is equal to the total number of atoms present on the product side.

The unbalanced chemical equation is as follows,

                             Ca ( s ) + N 2 ( g )  →  Ca 3 N 2 ( s )

To balance this equation, you need to look at how many atoms of each element are present on each side of the chemical equation.

 Calcium has  1  atom on the reactant and  3  on the products side. To balance the reaction we need to multiply the calcium atom by  3  on the reactants side.

                            3 Ca ( s ) + N 2 ( g )  →  Ca 3 N 2 ( s )    

Now  Nitrogen has a coefficient of  2  on both sides of the reaction. Hence the balanced chemical equation will thus be

                              3 Ca ( s ) + N 2 ( g )  →  Ca 3 N 2 ( s )

Answer:

it could be a B. egg cell or C. A stem cell but im pretty sure the answer is egg cell

hopes it helps!

The cell which is formed by the process of Meiosis is called as an egg cell. The correct option is B.

Meiosis is a type of cell division that produces four daughter cells, each with half the number of chromosomes as the original cell. This process is essential for sexual reproduction, where haploid gametes, such as egg and sperm cells, are produced. Meiosis is called as reductional division type of cell division.

Through the process of Meiosis, four daughter cells are formed which are not exactly same or identical to the parent cell.

Bacterial cells do not undergo meiosis as they reproduce asexually through binary fission. Stem cells and brain cells are also not formed by meiosis but by mitosis, a type of cell division that produces identical daughter cells with the same number of chromosomes as the original cell.

Therefore, the correct option is B.

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Answer:When frozen, water molecules take a more defined shape and arrange themselves in six-sided crystalline structures. The crystalline arrangement is less dense than that of the molecules in liquid form which makes the ice less dense than the liquid water. When water freezes, the volume expands by approximately 9%.

Explanation:

Answer:

                       41.51 g of CO

Explanation:

                      The balance chemical equation for given double displacement reaction is,

                                     Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂

Step 1: Calculate moles of Fe₂O₃:

Moles = Mass / M.Mass

Moles = 78.9 g / 159.68 g/mol

Moles = 0.494 moles

Step 2: Calculate moles of CO:

According to equation,

                   1 mole of Fe₂O₃ reacted with  =  3 moles of CO

so,

                 0.494 moles of Fe₂O₃ will react with  =  X moles of CO

Solving for X,

                      X  =  0.494 mol × 3 mol ÷ 1 mol

                      X =  1.482 moles of CO

Step 3: Calculate Mass of CO as:

Mass = Moles × M.Mass

Mass = 1.482 mol × 28.01 g/mol

Mass = 41.51 g of CO

Answer:

1 is the the earth and 2 is all of the above

Explanation:

Answer:

The answer is for 1. Earth.   2. Burrows

These imprints give scientists clues as to how these animals lived.

Explanation:

Answer:

(a bit of heat) and light

Explanation:

it has the resistance in it so it will give heat when surpassed by a high tension

Answer:2. 109 g NaCl

3. 31.9 g ZnCl2

4. 15.4 g Al2O3

Explanation: First find moles of the given compound

Next do the mole ratio between both compounds

Convert moles to mass.

Answer:

Explanation:

If a strong acid   HA  = H=  + A-  100%

pH = -log [H+] = - log 0.1= -(-1)=1

Answer:

The pH is 1.  I got this question right on my assignment.

NaHCO₃ + HCl → NaCl + H₂O + CO₂

Explanation:

NaHCO₃ + HCl → NaCl + H₂O + CO₂

When Sodium bi carbonate (NaHCO₃) reacts with hydrochloric acid (HCl), it forms table salt (NaCl), water ( H₂O ) and Carbon di oxide (CO₂) gas is evolved.

Here base reacts with acid to form salt and it is the neutralization reaction.

Answer:

                      0.2934 g of N₂

Explanation:

                    The balance chemical equation for given reaction is as follow;

                              2 NH₃ + 3 CuO → 3 Cu + N₂ + 3 H₂O

Step 1: Calculate Moles of CuO as;

                Moles  =  Mass / M.Mass

                Moles  =  2.5 g / 79.54 g/mol

                Moles  =  0.0314 moles of CuO

Step 2: Find out moles of N₂ as;

According to equation,

                      3 moles of CuO produced  =  1 mole of N₂

So,

                0.0314 moles of CuO will produce  = X moles of N₂

Solving for X,

                       X =  0.0314 mol × 1 mol / 3 mol

                      X =  0.0104 moles of N₂

Step 3: Calculate Mass of N₂ as;

                    Mass  =  Moles × M.Mass

                    Mass  =  0.0104 mol × 28.01 g/mol

                    Mass  = 0.2934 g of N₂

Answer:

A

Explanation:

Answer:

Evaporation

Explanation:

I just took the quiz

Answer:

The atomic number of silicon is 14 while atomic mass of carbon is 14.

Explanation:

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

In given atoms ¹⁴₆C  and ²⁸₁₄Si the atomic mass of carbon is 14 while the atomic number of silicon is 14. It means silicon has 14 electrons or protons while carbon has 6 protons or electrons because its atomic number is 6. Carbon has 6 protons and 8 neutrons in its nucleus while silicon has 14 protons and 14 neutrons in its nucleus.

In C:

Number of neutrons + protons = 8 + 6 = 14 amu (mass number)

Number of electrons = 6

In Si:

Number of neutrons + protons = 14 + 14 = 28 amu (mass number)

Number of electrons = 14

Answer:

132

Explanation:

Answer:

132

Explanation:

Explanation:

In the given figure we need to find the total resistance and total voltage .

We know that :

So, in this circuit : R1=12 ohm

R2=8 ohm

R3=10 ohm

Ammeter reading = 10A

so, they are in series therefore ,

Total R = R1 + R2 +R3

R=12 +10+8=30 ohm

To find voltage we have : V=IR

                                          V =10 x 30=300Volts

Answer:

The total resistance in this circuit is 30 ohms.

The battery voltmeter should read 300 volts.

Explanation:

I got it right. hope this helps !! :DD

Answer:

A substance that produces hydrogen ions in solution is AN ACID.

Explanation:

Answer:

Physical changes are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds.[1]

Physical changes occur when objects or substances undergo a change that does not change their chemical composition. This contrasts with the concept of chemical change in which the composition of a substance changes or one or more substances combine or break up to form new substances. In general a physical change is reversible using physical means. For example, salt dissolved in water can be recovered by allowing the water to evaporate.

A physical change involves a change in physical properties. Examples of physical properties include melting, transition to a gas, change of strength, change of durability, changes to crystal form, textural change, shape, size, color, volume and density.

An example of a physical change is the process of tempering steel to form a knife blade. A steel blank is repeatedly heated and hammered which changes the hardness of the steel, its flexibility and its ability to maintain a sharp edge.

Many physical changes also involve the rearrangement of atoms most noticeably in the formation of crystals. Many chemical changes are irreversible, and many physical changes are reversible, but reversibility is not a certain criterion for classification. Although chemical changes may be recognized by an indication such as odor, color change, or production of a gas, every one of these indicators can result from physical change.

Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions.

Physical properties are characteristics of matter that can be observed or measured without changing the substance's chemical composition. Chemical properties, describe how a substance interacts with other substances, indicating its ability to undergo chemical reactions.

Physical properties are those that can be observed or measured without altering the chemical identity of a substance. These include characteristics such as color, density, melting point, boiling point, odor, and conductivity. For example, when you melt ice to form water, it remains H2O throughout the process, so the change in state (from solid to liquid) is a physical change. Similarly, the change in color of a metal when it's heated is also a physical property, as it doesn't alter the metal's composition.

Chemical properties, on the other hand, describe how a substance interacts with other substances and its ability to undergo chemical reactions. These properties include reactivity, flammability, toxicity, and the ability to rust or corrode. For instance, when iron rusts upon exposure to oxygen and moisture, it's undergoing a chemical change because its composition changes from pure iron (Fe) to iron oxide (Fe2O3).

In summary, physical properties involve observable characteristics that don't change a substance's composition, while chemical properties describe a substance's behavior in chemical reactions and how it can transform into different substances.

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Answer:

when humans burn fuel or cut down trees , the increase level of carbon dioxide in the atmosphere

Answer:

35 percent

Explanation:

Answer:92%

Explanation:

Answer:

Bleach and seawater are identified wrong.

Explanation:

Acids have an pH that is lower than 7 and bases have a pH of higher than 7 and (pH 7 is neutral)

We can observe from the table that bleach has a pH of 13 which is higher than 7 and shows basic characteristics

As for seawater the table shows it has a pH of 8 which is also a base. Therefore the answer is 3rd option "Bleach and seawater should be identified as bases".

Answer:

takes in carbon dioxide, puts out oxygen.

Explanation:

The true characteristics of respiration are that it produces ATP, occurs constantly, and responds to temperature changes. Respiration does not happen in chloroplasts, depend on light, or involve taking in carbon dioxide and releasing oxygen.

The true characteristics of respiration include: produces ATP, occurs around the clock, and responds to changes in temperature. Respiration is a biochemical process where cells break down glucose and other molecules to produce ATP (adenosine triphosphate), which provides energy for various cell processes. It happens continuously, regardless of whether it's day or night, hence it 'occurs around the clock'. Although it doesn't directly depend on external temperature, respiration rates can vary with temperature changes because enzymes involved in this process are sensitive to temperature.

However, it is not true that respiration 'takes place in the chloroplasts' or that it 'is dependent on light'. These characteristics are related to photosynthesis, not respiration. Additionally, respiration 'takes in oxygen and puts out carbon dioxide', not the other way round.

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Answer:

Element:

Zinc case

Carbon rod

Compound:

Bitumen

ammonium chloride

Mixture:

Brass cap

carbon and manganese oxide

Explanation:

Elements are considered as pure substances that are made up of only one atom. A zinc case is made up of the metal zinc, which has a negative electrical polarity, that works as the anode in a battery.  The carbon rod is also a component you can find in a battery that serves as the cathode.

Compounds are pure substances as well that are made up of two or more atoms chemically bonded. They cannot be separated through physical means. Examples would be bitumen (pitch) which is a hydrocarbon. Ammonium chloride, is an inorganic compound. It is a salt that can be used as a diuretic.

Mixtures are made up of two or more substances or solutions. They are not chemically bonded, so that means that there are physical ways to separate them. A brass cap is a mixture of different metals, specifically zinc and copper.

Carbon and manganese is a powdered mixture that can be found inside a battery or a dry cell as well. When the battery is powered up, this mixture is then converted into a compound called manganese dioxide.

Answer:

that's a hard one

Explanation:

Answer:Zn + 2 HCl => ZnCl2 + H2

Explanation: Zinc has 1 atom in the reactant and product side

2 atoms for H on both sides and 2 atoms of chlorine in the reactant and product side.

6.7 grams of lithium chloride will be produced.

Lithium chlorate is LiClO₃ and lithium chloride is LiCl. The reaction is,

2LiClO₃ = 2LiCl +3O₂.

So here, 2 moles of lithium chlorate produces 2 moles of lithium chloride.

Or, one molecule of lithium chlorate will produce one mole of lithium chloride.

Molecular weight of lithium chlorate =[tex]6.9 + 35.5 + 16\times3[/tex] = 90.4.

So, 14.3 grams of lithium chlorate has 0.16 moles of lithium chlorate.

Thereby, moles of lithium chloride produced is 0.16 moles.

Molecular weight of lithium chloride = [tex]6.9+35.5[/tex] = 42.4 grams.

So weight of lithium chloride produced = [tex]42.4 \times 0.16[/tex] = 6.7 grams.

Thus, weight of lithium chloride produced will be 6.7 grams.

Answer:

6.25 hours

Explanation:

From the question;

We need to determine the time it will take for her to knit 300 rows

4 rows = 5 minutes

300 rows = ?

= (300 × 5 ) ÷ 4

= 375 minutes

But, 1 hour = 60 minutes

Therefore;

= 375 ÷ 60

= 6.25 hours

Thus, it will take penny 6.25 hours to knit 300 rows

It will take her 6.25 hours to knit 300 rows.

Given:

Penny can knit 4 rows in 5 minutes

4 rows = 5 minutes

To find:

Time for knitting 300 rows=?

Time = (300 × 5 ) ÷ 4

Time = 375 minutes

As we know, 1 hour = 60 minutes

Thus,

Time= 375 ÷ 60

Time= 6.25 hours

So, it will take 6.25 hours to knit 300 rows.

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Large crystals are formed when igneous rocks cool very slowly.

Answer:

igneous rocks cool very slowly

Explanation:

Hope this helps√

Answer: Al20

Explanation:

Al2O3, or aluminum oxide, has a higher percentage of aluminum content (~52.9%) than Al(NO3)3, aluminum nitrate (~12.7%). This is due to Al2O3 containing two aluminum atoms in its formula, whereas Al(NO3)3 contains only one.

To determine which compound has a higher percentage of aluminum, we need to compare the aluminum content in Al2O3 and Al(NO3)3.

In Al2O3, also known as aluminum oxide, there are two aluminum atoms and three oxygen atoms. The molar mass of Al2O3 can be calculated by adding the atomic masses of 2 aluminum atoms (2x27 g/mol) and 3 oxygen atoms (3x16 g/mol), which amounts to 102 g/mol. The mass of aluminum in the compound is 54 g/mol (2x27 g/mol), resulting in an approximate aluminum content of 52.9% by mass for Al2O3.

For Al(NO3)3, aluminum nitrate, it contains one aluminum atom and three nitrate groups. The molar mass of Al(NO3)3 is comprised of the mass of one aluminum atom (27 g/mol) plus the mass of three nitrate ions (3x(14+3x16) g/mol), which sums up to 213 g/mol. Here, the aluminum's mass percentage is about 12.7%.

Comparing these percentages, Al2O3 has a higher percentage of aluminum than Al(NO3)3.

Answer:

FAT TOM

Explanation:

FAT TOM is used in food industry which describe six suitable conditions that promote the growth of  bacteria.

Acronym of FAT TOM is

Food , acidity , time. temperature , oxygen and moisture.

Food contains the nutrients and other favorable requirements which is required for bacterial growth and it causes the food spoilage and if taken by human can cause food poisoning.

The acronym FATTOM is often used to describe factors essential for bacterial growth. Understanding these conditions is important for protein production using bacteria. Protein folding is the process by which a protein assumes its functional three-dimensional structure.

The acronym that describes conditions that promote bacterial growth is not specified in the provided materials, but often FATTOM is used to describe the factors essential for bacterial growth, which stands for Food, Acidity, Temperature, Time, Oxygen, and Moisture. Bacterial growth is of interest in various fields, including those seeking to collect protein. Bacteria can be used to express proteins which are later harvested for research or pharmaceutical purposes.

Protein Folding

Protein folding is the process by which a protein structure assumes its functional shape or conformation. Proper folding is crucial for a protein to function correctly. Misfolded proteins can lead to diseases such as Alzheimer's and Parkinson's. Understanding the conditions for bacterial growth allows for optimizing protein expression and ensuring proper protein folding during production.

Conditions for Bacterial Growth

To culture bacteria and promote growth, enrichment culture media are often used, which favor the expansion of specific bacteria presenting in low numbers. Environmental conditions affecting bacterial growth include temperature, pH, oxygen levels, and other factors like osmotic and barometric pressure. Categories of bacteria, such as psychrophiles and thermophiles, have unique growth requirements that must be met to thrive.