Why are elements on the periodic table not arranged by mass

If you've done stoichiometry already, it's easiest to do enthalpy problems like this in the same way where your ∆H is just part of the 'railroad tracks'.

-34.2 kJ (2 mol KClO3/-89.4 kJ) = 0.765 mol KClO3

Answer:

Electrons are transferred from atoms of sodium to atoms of phosphorus. This transfer makes the sodium atoms positive and the phosphorus atoms negative. As a result, the sodium and phosphorus atoms strongly attract each other.

Explanation:

The dose of the medicine per one kilogram of a body is 2.5 mg then , the dose of medicine required for 66 lb weight or 29.8 Kg is 74.5 mg.

Dose of a medicine is the amount of that medicine required to be taken for one time. It can be measured per Kg of body and the dose of medicine can be g or mg.

lb is a unit of weight. Generally we are using kilogram (Kg) unit of for kg. One lb weight = 0.453 kg.

Hence, 66 lb in kilogram weight is written as: 66 × 0.453 Kg = 29.8 Kg. The dose of medicine is 2.5 mg/kg which means, 2.5 mg is required for 1 Kg body.

The dose of the medicine required for 66 lb or 29.8 Kg is calculated by multiplying the dose required for 1 kg to the actual weight of the child as follows:

Dose =  29.8 × 2.5

         = 74.5 mg.

Thus, the child that weighs 66 lb or 29.8 kg is required to take the medicine of 74.5 mg dose.

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The thermal energy will affect the temperature of road and increase the temperature which causes cracks on the roads after some times. Thus the construction team must use temperature resistant material.  

Thermal energy is defined as internal energy present in a thermodynamically balanced system as a result of its temperature.

It can also be defined as the energy derived from matter's temperature.

There are three types of thermal energy transfer.

Thus, the  thermal energy will affect the temperature of road and increase the temperature which causes cracks on the roads after some times. Thus the construction team must use temperature resistant material.  

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378mL is the volume of a 10% m/v aqueous solution that contains 37.8g of HN03

A solution in which the solvent is water is referred to as an aqueous solution. By adding (aq) to the appropriate chemical formula, it is typically shown in chemical equations. For instance, Na+(aq) + Cl would be used to represent a table salt solution (also known as sodium chloride, or NaCl) in water (aq).

The word aqueous, which derives from the Latin word aqua, means being or consisting of water. Water is a common solvent in chemistry because it works great as a solvent and is also readily available. In experiments, water is frequently used as the solvent; therefore, unless otherwise specified, the term "solution" refers to an aqueous solution.

The mass of HNO3 =  37.8g

The mass is 10% m/v of the solution which implies

10/100 = mass/ volume

Volume = 10mass

Volume = 10(37.8g)

Volume = 378mL

Thus, 378mL is the volume of a 10% m/v aqueous solution that contains 37.8g of HN03

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The percent by mass of potassium chlorate in the mixture is 62.46 %

Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formulation KClO₃. In its natural form, it is a white crystalline substance. After sodium chlorate, it's far the second one maximum not unusual chlorate in commercial use.

Potassium chloride, also referred to as potassium salt, is used as a medicine to treat and prevent low blood potassium. Low blood potassium may also occur due to vomiting, diarrhea, or certain medications.

A aggregate is a material made of two or more extraordinary chemical materials which are not chemically bonded. A combination is the bodily aggregate of two or greater substances wherein the identities are retained and are combined in the shape of answers, suspensions and colloids

KClO₃ + KCl = 9.47 gram   ---------  sample before heating

KClO₃ + KCl = 7.11 gram      ----------  sample mass after heating

mass of oxygen = 9.47 - 7.11 = 2.36 gram

Therefore mass of KClO₃ in an mixture is = 7.11/2 + 2.36

                                                                     = 5.915 gram

Therefore, the percent by mass of potassium chlorate in the mixture = 5.915/9.47 × 100

= 62.46 %

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A cold air mass colliding with a hot air mass triggers the development of a tornado and is denoted as option D.

This is referred to as a violently rotating column of air and it is caused as a result of different types of factors such as the humidity , temperature etc.

A tornado is usually very violent and it is formed when cold air mass collides with a hot air mass and is often characterized by a green color in most situations and is therefore the reason why option D was chosen as the most appropriate choice.

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Answer

[H+] = 7.94x10^-6 M

Explanation

Given:

pH = 5.1

Required: The concentration of H+

Solution

pH = -log[H+]

5.1 = - log [H+]

[H+] = 10^-5.1

[H+] = 7.94x10^-6 M

Water vapor with a total mass of 10.29 g occupies 6.07 x 10⁻5 mL of volume.

Density of substance is defined as the mass of the substance per unit of its volume.

We know that,

Density of water vapor at 100°C and standard pressure is 5.9 x 10⁻⁴ g/cm³. To calculate volume, we will use the formula of density, which is -

density =   mass  

               volume

volume = mass x density

We know from the question that,

mass = 10.29 g

Substituting values in the equation,

volume = 10.29 x 5.9 x 10⁻⁴

volume = 6.07 x 10⁻⁵ mL

Hence, the volume occupied by the water vapor is 6.07 x 10⁻⁵ mL

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Explanation:

Equilibrium occurs in a reversible reaction. This occurs when in a reaction the products formed react to reproduce the reactants. So basically, the forward and reverse reaction occur at equal rates.

Answer:

The correct answer is B.

From the calculation that is based on the ICE table shown, the pH of the solution is  1.8.

Let us recall that the KNO2 is a salt of the nitrous acid. Our concern now would be on the nitrous ion and we are going to make up the ICE table from the following;

    NO2^-(aq) + H2O(l) ⇄  HNO2(aq) + OH^-(aq)

        HNO2 (aq) ⇄   H^+(aq) +  NO2^-(aq)

I        0.59                 0                0

C      -x                      +x               +x

E     0.59 -x             x                  x

Now we know that the Ka of HNO2 is 4.0x10^-4.

Ka = [H^+] [NO2^-]/[ HNO2]

4.0x10^-4 = x^2/0.59 -x

4.0x10^-4(0.59 -x) = x^2

2.36 x10^-4 - 4.0x10^-4x = x^2

x^2 +  4.0x10^-4x - 2.36 x10^-4  = 0

x=0.015

pH = -log(0.015)

pH = 1.8

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Answer:

Explanation:

Here, we want to balance the given chemical equation

We can start by balancing the oxygen atoms

We have 7 on the left and 2 on the right

To make a balance, we place 7 before the molecular oxygen on the left and 2 on the given oxide

That means we would be having 4 Rh on the left

To balance the Rh, we have to place 4 on the left side

Thus, we have the balanced equation as:

One mole of a substance contains 6.02×10²³ atoms. This number is called Avogadro number. The mass of 532 atoms of Fe is only 4.93×10⁻²⁰ g.

Any substance which contain 6.02×10²³ atoms is called one mole of the substance.  One mole of iron (Fe) is 55.85 g and it contains Avogadro number of atoms or  6.02×10²³ atoms.

Iron is a transition metal with electropositive character and is an essential metal in construction field and in electronic devices.

The atomic mass of iron = 55.85 g/mol.

If 55.85 g of Fe contains 6.02×10²³ atoms, the mass of iron which contain 532 atoms is then calculated as follows:

mass of iron  = (532 × 55.85 g) / 6.02×10²³

                      = 4.93×10⁻²⁰ g.

Hence, The mass of 532 atoms of iron is only 4.93×10⁻²⁰ g.

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The average atomic mass of the fictitious element Az is 326.2 amu

The average atomic mass (on occasion referred to as atomic weight) of an element is the weighted average mass of the atoms in an obviously going-on sample of the element. average masses are typically expressed in unified atomic mass gadgets.

The atomic mass of detail is the common mass of the atoms of an element measured in the atomic mass units (AMU, also called daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of every isotope is improved via the abundance of that specific isotope.

The atomic mass is a median of an element's atomic hundreds, weighted via the herbal abundance of each isotope of that detail. it is a weighted common because exclusive isotopes have one-of-a-kind hundreds. An atomic mass unit is 1/12th of the mass of a 12C atom.

Average atomic mass = Σ % abundance × mass

                                     = 325.2 × 7/9 +  329.6 × 2/9

                                      = 252.93 + 73.24

                                      = 326.17 amu

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speed of the electron  =  0.93*speed of light

                                   = 0.93*3.00 × [tex]10^{8}[/tex] m/s*(0.6214 mi/1 km)*(3600 s/hr)

                                   = 6.24X [tex]10^8[/tex] mi/hr

Speed is defined as the rate at which the position of an object changes in any direction.

There are four types of speed and they are:

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Taking into account the reaction stoichiometry, 65.32 grams of B₂H₆ will react with 7.1 mol of O₂.

In first place, the balanced reaction is:

B₂H₆ + 3 O₂ → B₂O₃ + 3 H₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

The following rule of three can be applied: If by reaction stoichiometry 3 moles of O₂ react with 27.6 grams of B₂H₆, 7.1 moles of O₂ react with how much mass of B₂H₆?

mass of B₂H₆= (7.1 moles of O₂× 27.6 grams of B₂H₆)÷ 3 moles of O₂

mass of B₂H₆= 65.32 grams

Finally, 65.32 grams of B₂H₆ is required.

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Answer

pH = 1.26

Explanation

If the [H3O+] of an aqueous solution is 0.055 M, then its pH can be calculated using the pH formula below.

The pH of an aqueous solution of 0.055 M is 1.26

Answer:

Criteria for spontaneity in terms of free energy change: (i) If ∆G is negative, the process is spontaneous. (ii) If ∆G is positive, the direct process is non-spontaneous. (iii) If ∆G is zero, the process is in equilibrium.

Nuclear energy produces electricity or electrical energy that can be used to power homes, schools, businesses, and hospitals.

A type of energy emitted by an atom's nucleus, which is composed of protons and neutrons, is known as nuclear energy. Fission, which occurs when atoms' nuclei split into numerous portions, and fusion, which occurs when nuclei fuse together, are the two methods in which this type of energy can be created.

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Answer:

There are three major hazards that may be introduced into the food supply any time during harvesting, processing, transporting, preparing, storing and serving food. These hazards may be microbiological, chemical or physical.

Explanation:

microbiological hazards

Microbiological hazard occurs when food becomes contaminated by microorganisms found in the air, food, water, soil, animals and the human body. Many microorganisms are helpful and necessary for life itself. However, given the right conditions, some microorganisms may cause a foodborne illness. Microorganisms commonly associated with foodborne illnesses include bacteria, viruses and parasites.chemical hazardsChemical hazards can occur at any point during harvesting, storage, preparation and service. When toxic chemicals used for pest control or for cleaning and sanitizing food contact surfaces and food preparation equipment come into contact with food, the food may be contaminated by those chemicals.Toxic metals such as copper, brass, cadmium, lead and zinc can be a source of chemical contamination. Zinc, used in galvanized containers (garbage cans) and in gray enamelware containers which may be plated with anatomy or cadmium, can make acidic foods such as orange juice or tomato sauce and pickles poisonous. Pottery dishes with lead glazes should not be used to prepare or serve food.Intentionally added chemicals help to maintain a food’s freshness or to enhance flavors in foods. Check the food ingredient label for more information about the additives. Excessive use of some additives has been linked (see Fact Sheets on Food Allergies and Food Additives) to cases of lethal allergic reactionsparticularly among sensitive individuals, in particular, asthmatics.Foodservice establishments are prohibited by law from using sulfites to maintain product freshness. However, they are still approved for use in some food processing operations, for example, processing shrimp and manufacturing wine. If they are used, the product must be clearly labeled.physical hazardsPhysical hazards usually result from accidental contamination and /or poor food handling practices. Examples include, slivers of glass, human hair, nails, false nails, nail polish, pieces of jewelry, metal fragments from worn or chipped utensils and containers, dirt, stones, frilled toothpicks.Pesticides may leave residues on fruits and vegetables. In general, these residues can be removed by scrubbing the surface and washing with water.Food irradiation is classified as a food additive and is regulated by the Food and Drug Administration (FDA). Irradiation is a process which destroys pathogenic and spoilage microorganisms without compromising safety, nutrition or quality and significantly lengthens storage life. In general, spices are irradiated as a means of controlling bacterial growth and mold. According to Dr. Donald Thayer of the USDA Agricultural Research Service, irradiation looks promising as a treatment for controlling cylospora in fresh produce like raspberries . Contact your local Cooperative Extension office for the latest information on irradiation.

Answer:

A mixture is a combination of two or more substances in any proportions. The substances in a mixture do not combine chemically, so they retain their physical properties. A homogeneous mixture has the same composition throughout.

Answer:

it's the last one

Answer:

C3H6O3

Explanation:

It is one of the simplest molecules to compare against other molecules, such as sugars and amino acids.

The distance between two consecutive crests or troughs of a wave, particularly in the case of electromagnetic or sound waves, is known as its wavelength.

The wavelength (in nanometers) or frequency of light is used to quantify it (in Hertz). Like with radio waves, they can also be as long as centimetres or metres. It is represented by and inversely proportional to wave frequency.

What distinguishes frequency from wavelength?

Frequency and wavelength are intimately related, particularly in the context of light. Frequency is determined by the number of waves that pass through a single place over a particular period of time, whereas wavelength is the distance between two successive troughs or crests.

The crest of a wave is the part of transverse waves that are above the mean level. The wave's trough is the region of transverse waves that lies below the mean level. The distance between two succeeding crests or troughs is known as the wavelength.

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Non-renewable resources are resources found by humans as a source of energy and such resources cannot be replenished. Therefore, such resources should not be wasted.

Nature is the epitome of beauty and grace but as humans grow up they forget the shining and uplifting virtues. People should use resources responsibly. Non-renewable resources come from the earth. The supply is finite and could take billions of years to replenish.

In the past, many non-renewable energies were relatively cheap to generate. However, as supplies continue to dwindle the cost of this extraction is likely to increase, prompting customers to turn to alternative power sources such as solar and wind. The most common examples of natural resources include crude oil coal uranium and mineral resources such as gold. A subset of non-renewable resources includes crude oil and natural gas. Both substances are made of organic carbon materials and change shape over time after being heated and compressed.

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First of all we must know this:

1 mol of Ti,= 47.90 g of Ti, furthermore we can say that:

1 mol Ti = 47.90 g Ti = 6.022x10^23 formula units (atoms, molecules, ions, etc.) and in this case, we work with atoms of Ti.

Procedure:

47.90 g (1 mol) of Ti ------------------ 6.022x10^23 atoms of Ti

X ------------------ 5.74x10^22 atoms of Ti

X = 4.600 g of Ti

Answer: 4.600 g of Ti

The volume of 79.1 liters of oxygen (O₂) will be produced at a temperature of 370°C and 1520 torr if 2 moles of KClO₃ decompose.

The molar volume (Vm) is the volume occupied by 1 mole of a chemical element or a chemical compound at Standard Temperature and Pressure (STP). Molar gas volume is one mole at a specific temperature and pressure and has a fixed volume.

The Molar volume is inversely proportional to density and directly proportional to molar mass. One mole of any gas at STP occupies a volume of 22.4 liters.

Given, the 2moles of  KClO₃ will produce  O₂ gas = 3moles

The volume occupied by 3 moles of the oxygen gas at 370°C and 1520 torr is :

Given, n = 3, P = 1520 torr = 2atm and T = 370°C  = 643 K

PV = n RT

(2atm) V = (3)(0.082 atm L /K) (643K)

V =79.1 L

Therefore, the volume of oxygen gas produced will be equal to 79.1 Litres.

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1) List the known and unknown quantities.

Sample: luminol.

Mass: 10.0 g.

Volume: 75.0 mL.

Molarity: unknown.

2) Set the equation.

3) Conversion of units.

3.1-Convert mass to moles.

The molar mass of luminol (C8H7N3O2) is 177.1601 g/mol.

3.2-Convert mL to L.

1 L = 1000 mL

4) Plug in the known quantities.

The molarity of the stock solution is 0.75 M C8H7N3O2.

.

Answer

d. They are very far apart and very energetic.

Explanation

The particles in the solid are touching with very little space between them. The particles in a liquid usually are still touching but there are some spaces between them. The gas particles have big distances between them.

Gas particles are in constant rapid motion in random directions. The fast motion of gas particles gives them a relatively large amount of kinetic energy.

Explanation:

The use of pH indicators in the titration process is useful to determine the end point of the titration, indicating that the entire sample is reacted.

Answer: To show when the reaction has reached or past the equivalence point.

Non-renewable resources are resources found by humans as a source of energy and such resources cannot be replenished. Therefore such resources should not be wasted.

The earth is rich in resources. Some are unlimited others are inherently limited. Renewable resources are unlimited and can be replenished. However non-renewable resources are finite and must be used carefully to ensure long-term use for future generations. Wood is a renewable resource. This means you can grow additional resources in place of felled wood.

Non-renewable energy comes from resources that are depleted or not replenished over and over again throughout our lifetime. Most non-renewable energy sources are fossil fuels such as coal oil and natural gas. Carbon is the main element of fossil fuels. Air and water are also renewable natural resources. They don't grow like trees or have babies like animals. But they are constantly updated. They move cyclically.

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