What did ancient astronomers think areas of the moon called mares might be? mountains seas craters terrae

Potassium Chloride and sodium chloride is a combination ofmineral supplement that may be helpful in heart prostration

Final answer:

Dmitri Mendeleev is credited with creating the first recognized periodic table of elements in 1869, which included predictions for undiscovered elements, making it a groundbreaking contribution to chemistry.

Explanation:

The answer to the student's question is a. True. Dmitri Mendeleev is widely credited with creating the first periodic table of the elements in 1869. This early version of the periodic table organized elements by increasing atomic mass and showcased periodic trends. Mendeleev also boldly left gaps in his table for undiscovered elements, predictively detailing their possible properties, many of which were later confirmed with the discovery of elements like gallium and germanium. While German chemist Lothar Meyer also published a similar table around the same time, Mendeleev's periodic table is generally recognized as more significant due to its predictive nature and earlier publication.

Explanation:

In chemistry, accuracy refers to how close a measurement is to its standard or known value. ... Precision refers to how close two or more measurements are to each other, regardless of whether those measurements are accurate or not. It is possible for measurements to be precise but not accurate.

In chemistry, precision is the consistency of repeated measurements under unchanged conditions, reflecting the reliability of data. Precise measurements are critical for reproducibility and may inform on the purity of substances, illustrating a substance's homogeneous nature.

In chemistry, precision refers to how closely a measurement matches the same measurement when it is repeated under unchanged conditions. It is an indication of the consistency among a set of results. Precision is essential in chemistry because it ensures that experiments and measurements can be reproduced, which is a fundamental aspect of the scientific method. The precision of a measuring tool is also dependent on the size of its measurement increments; smaller increments generally allow for more precise measurements.

When considering both accuracy and precision, a set of measurements can be precise without being accurate and vice versa. For example, if a series of measurements are close to each other but far from the known or accepted value, they are precise but not accurate. Conversely, a single measurement can be accurate if it is close to the known value, even if it is not repeated to assess precision.

The concepts of precision and purity are also related in chemistry. A pure substance is a homogeneous substance that has a constant composition. Having precise measurements helps chemists in determining the purity of substances, as consistent properties and measurements suggest that a substance is pure and not contaminated with other materials.

Answer:

1.69×10^25 grams

Explanation:

First convert molecules to moles and then convert moles to grams by multiplying by the molar mass which is 28.0g and you get this answer!!

Hope this is right

Answer:

The object will move to the right .

Explanation:

The force in the right side of the object is 20N  which is more than the force of any other side according to the given question.

   As the force in the right side of the object is greater than that of other sides the the object will move to the right.

Answer:

[tex](_{1} ^ {1}\textrm{H})[/tex]  is the correct choice that is option A.

Explanation:

An electron has [tex]\frac{1}{1836}[/tex] times the mass of a proton, but an equal and opposite negative charge.

Lets [tex]_{A}^{Z}\textrm{X}[/tex] is any element represented here.

Where [tex]Z[/tex] is the number of protons as well as its atomic number.

And

[tex]A[/tex] is the mass number which is the number of protons and neutrons in any atom.

Note: We know that Hydrogen [tex](_{1} ^ {1}\textrm{H})[/tex] is devoid of neutron,so number of neutrons in a Hydrogen atom is zero.

Then

[tex](_{1} ^ {1}\textrm{H})[/tex] is also a representation of single proton.

So [tex](_{1} ^ {1}\textrm{H})[/tex] is the right choice that is option A.

The mass of an electron is approximately 1/1836 times the mass of a proton.

The mass of an electron is approximately 1/1836 times the mass of a proton (choice B). This means that the mass of the electron is much smaller compared to the mass of the proton. For example, in a hydrogen atom, which consists of just one proton and one electron, the mass of the proton is about 1836 times greater than the mass of the electron.

Answer:

the answer is current curricular

Answer:

current curricular

Explanation:

117 mL of 0.210 M K₂S solution

Explanation:

The question asks about the volume of 0.210 M K₂S (potassium sulfide) solution required to completely react with 175 mL of 0.140 M Co(NO₃)₂ (cobalt(II) nitrate).

We have the chemical reaction:

K₂S + Co(NO₃)₂ → CoS + 2 KNO₃

molar concentration = number of moles / volume (L)

number of moles = molar concentration × volume

number of moles of Co(NO₃)₂ = 0.140 × 175 = 24.5 mmoles

We see from the chemical reaction that 1 mmole of Co(NO₃)₂ is reacting with 1 mmole of K₂S, so 24.5 mmoles of Co(NO₃)₂ are reacting with 24.5 mmoles of K₂S.

volume = number of moles / molar concentration

volume of K₂S solution = 24.5 / 0.210 = 117 mL

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To convert the units of concentration from mol/g*cm² to mol/kg*m², one should convert grams to kilograms and cm² to m² using known conversion factors. After the conversions, the units will be successfully changed to mol/kg*m².

The question provided is about the conversion of units of concentration from mol/g*cm² to mol/kg*m². This is a common type of problem in chemistry when dealing with different units of concentration. The conversion will involve changing the unit of mass from grams to kilograms, and changing the unit of area from cm² to m².

To convert grams to kilograms, we need to know that 1 kg is equal to 1,000 g. Therefore, we multiply our value in g by (1 kg/1,000 g).

To convert cm² to m², we know that 1 m is equal to 100 cm, and therefore 1 m² is equal to 10,000 cm². So, we multiply our value in cm² by (1 m²/10,000 cm²).

After doing these calculations, we will have successfully converted the given concentration from mol/g*cm² to mol/kg*m².

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Answer:

If anything but H2O were found, it would be evidence of a chemical change. Therefore, 4 is the only viable evidence that it was a physical change of H2O liquid to H2O gas.

Answer:

4-[tex]H_{2}O_{(g)}[/tex]

Explanation:

Initially, the beaker contains distilled water which is liquid water at room temperature. When the beaker was placed on a hot plate and heat energy was applied the temperature of the system increases gradually until the boiling point was reached. Water generally boils at 100°C and at this temperature, liquid water changes to vapor or gas. In addition, liquid water and steam or water vapor are in equilibrium. Therefore, the presence of water vapor ([tex]H_{2}O_{(g)}[/tex]) indicates that the process is a physical change.

Answer:

C = Electrons are won and lost.

Explanation:

The oxidation reduction reactions are called redox reaction. These reactions are take place by gaining and losing the electrons and oxidation state of elements are changed.

Oxidation:

Oxidation involve the removal of electrons and oxidation state of atom of an element is increased.

Reduction:

Reduction involve the gain of electron and oxidation number is decreased.

Consider the following reactions.

4KI + 2CuCl₂  →   2CuI  + I₂  + 4KCl

the oxidation state of copper is changed from +2 to +1 so copper get reduced.

CO + H₂O   →  CO₂ + H₂

the oxidation state of carbon is +2 on reactant  side and on product side it becomes  +4 so carbon get oxidized.

Na₂CO₃ + H₃PO₄  →  Na₂HPO₄ + CO₂ + H₂O

The oxidation state of carbon on reactant side is +4. while on product side is  also +4 so it neither oxidized nor reduced.

H₂S + 2NaOH → Na₂S + 2H₂O

The oxidation sate of sulfur is -2 on reactant side and in product side it is also -2 so it neither oxidized nor reduced.

Oxidizing agents:

Oxidizing agents oxidize the other elements and itself gets reduced.

Reducing agents:

Reducing agents reduced the other element are it self gets oxidized.

The correct answer is C: Evaporation.

Further Explanation:

Liquids that become a gas goes through a process called evaporation. Evaporation occurs when something that is liquid heats up enough to become a gas form. The liquid is heated so quickly that the molecules in the liquid evaporate.

Condensation is the opposite of evaporation and this turns the gas into a liquid.

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To convert 4.82 mmol of diphenylmethanol to grams, calculate the molar mass of C13H12O to be 184.32 g/mol. Then, multiply 4.82 mmol by the molar mass and divide by 1000 mmol/mol to get 0.8886 grams.

To convert 4.82 mmol of diphenylmethanol (C13H12O) to grams, you first need to calculate the molar mass of diphenylmethanol. The molar mass is calculated by the sum of the atomic weights of each atom in the molecular formula. The molecular weights are approximately: Carbon (C) = 12.01 g/mol, Hydrogen (H) = 1.008 g/mol, and Oxygen (O) = 16.00 g/mol. Thus, the molar mass of C13H12O is (13x12.01 g/mol) + (12x1.008 g/mol) + (16.00 g/mol) = 184.32 g/mol.

Next, use the conversion factor that relates millimoles to grams using the molar mass:

4.82 mmol C13H12O x (184.32 g/mol) / (1000 mmol/mol) = 0.8886 g C13H12O

So, 4.82 mmol of diphenylmethanol is equivalent to 0.8886 grams.

Answer:

non-metal

Explanation:

Covalent bonds are formed when non-metal atoms are combined.

In the periodic table, that's groups 3A, 4A, 5A, 6A and 7A, all to the right of the "staircase" line.

Answer:

Balanced

Explanation:

2 Carbons per side

4 Hydrogens per side

3 Oxygen per side

1 Iron per side

Answer:

Balanced

Explanation:

For an equation to be balanced, the number of atoms of each element on the lefthand side and right hand side of the reaction equation must be exactly the same.

There are four hydrogen atoms on each side

There is one carbon atom on each side

There are three oxygen atoms on each side

There is one iron atom on each side.

This is how to know a balanced chemical reaction equation.

Answer:

Synthesis

Explanation:

Synthesis reaction:

It is the reaction in which two or more simple substance react to give one or more complex product.

General equation;

A + B → AB

The given reaction is synthesis reaction.

Chemical equation:

2Al + Cl₂ → 2AlCl

it is also redox reaction because oxidation reduction take place.

The oxidation state of aluminium and chlorine is zero on left side while it on right side aluminium become cation with charge of +1 and chlorine become anion with a charge of -1.

Aluminium is reducing agent while chlorine is oxidizing agent.

Oxidizing agents:

Oxidizing agents oxidize the other elements and itself gets reduced.

Reducing agents:

Reducing agents reduced the other element are it self gets oxidized.

Answer:

C. The food we eat is fresher because it is treated with preservatives

Answer:

Option-(B,C): Due, to having more advanced or modern farming techniques there is more land available for the construction of industrial buildings  and neighborhoods. While, the food we eat is fresher because it is treated with preservatives.

Explanation:

The modern farming techniques has provided with great benefits, as there is more space for building new structures and develop the industrial zones more frequently. As, there is now much space to have industries in the region,while the farms are much advanced these days. Along with that, the food is able to eaten after longer duration of time and is able to be supplied to much far distances across the borders to other countries or regions. Just because the food we eat is fresher because it is treated with preservatives.As, there are some modern techniques which has able us to preserve the food through any long season.

Answer:

twins

Explanation:

twins are genetically identical

500 Joules

We are given;

We are required to calculate the work done;

Thus, in this case;

Work done = 100 N × 5 m

                  = 500 Joules

Thus, the work done in moving the box is 500 joules

Answer:

4.08

Explanation:

Answer:

4.08

Explanation:

a . p .  e . x .

Answer: gasoline

Explanation: Gasoline is a mixture of many different hydrocarbons: alkanes (paraffins), cycloalkanes and alkenes (olefins). Salt and carbon dioxide are chemical compounds, aluminium (Al) is an chemical element.

Taking into account the definition of mixture, the correct answer is second option: gasoline.

A mixture is the combination or union of two or more elements or components that can be found in any state of matter.

Mixtures can be homogeneous, where the components are united in a uniform way and are not distinguished by the naked eye, or heterogeneous, which lacks uniformity, so that the substances or elements that make up the mixture can be distinguished.

Gasoline is a combination of several liquid, volatile and flammable hydrocarbons, that is, organic compounds formed only by carbon and hydrogen, obtained by fractional distillation of petroleum to which additives are added to improve its properties.

In others words, gasoline is a homogeneous mixture of hydrocarbons which are obtained from oil.

In summary, the correct answer is second option: gasoline.

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Answer: True

Explanation:

Photons do not have mass, so they are not considered matter. However, they do have a stationary state either, so they are not considered an object in Physics.

Answer:

The charge in the clouds can cause the ground to become positively charged.

Explanation:

During a thunderstorm, the important charging area is the central part or portion of the storm when air is moving in an upward direction. The temperature here ranges from -15 to -25 degree Celsius.  The ground has a slightly negative charge and when a thunderstorm comes the negative charge on the ground is repelled by the negative charge in the center of the storm. This makes the ground that is underneath the storm to become more positively charged.  

Answer:

The Venus flytrap consumes its food in the form of flies and other small insects not through the roots as other plants

Explanation:

Answer:

The thing about the venus fly trap which makes it so unique and are known for is its ability to digest insects.

Explanation:

The thing about the venus fly trap which makes it so unique and are known for is its ability to digest insects. In its name "fly trap" which are commonly house plants implies the ability of trapping insects for its nutrional value

5. It is one of the most important greenhouse gases linked to global warming, but it is a minor component of Earth’s atmosphere (about 3 volumes in 10,000), formed in combustion of carbon-containing materials, in fermentation, and in respiration of animals and employed by plants in the photosynthesis of carbohydrates.

The mass of oxygen and carbon required to produce 56 grams CO has been 32 grams and 24 grams respectively. The law that illustrates this has been the law of conservation.

The moles of product or reactant in a chemical reaction are given by the stoichiometric coefficient of the balanced chemical equation.

The given balanced equation has been:
[tex]\rm 2\;C\;+\;O_2\;\rightarrow\;2\;CO[/tex]

From the balanced chemical equation, for the formation of 2 moles of CO,1 mole of oxygen and 2 moles of carbon has been required.

56 g of CO has been equivalent as:

[tex]\rm Moles=\dfrac{Mass}{Molar\;mass} \\\\Moles\;CO=\dfrac{56}{28}\;mol\\\\ Moles\;CO=2\;moles[/tex]

The moles of CO produced has been 2 moles. Thus, the moles of oxygen and carbon required are:

The mass of oxygen required is 32 grams.

The mass of carbon required has been 24 grams.

The law that illustrates this is the law of conservation. According to the law of conservation, mass has not been lost in the chemical reaction.

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Answer:

[tex]\frac{PV}{T}=k[/tex]

Explanation:

Combine Gas law is a combination of  three gas laws which are  Boyle's Law, Charles' Law, and Gay-Lussac's Law.

Combine gas law states that the ratio of the product of pressure and volume and the absolute temperature of a gas is equal to a constant.

Hence the equation becomes:

[tex]\frac{PV}{T}=k[/tex]

where P = pressure,

V = volume,

T = absolute temperature,

k = constant.

Now we know that Kelvin = °Celsius + 273

For all gas law problems it is necessary to work in the Kelvin scale because temperature is in the denominator in the combined gas laws (P/T, V/T and PV/T) and can be derived in the ideal gas law to the denominator (PV/RT) . If we measured temperature in Celsius we could have a value of zero degrees Celsius and this would solve as no solution, as you cannot have zero in the denominator.

However, if we reached zero in the Kelvin scale this would be absolute zero and all matter would stop and therefore there would be no gas laws to worry about.

Atoms form ions by gaining or losing electrons. A cation forms when an atom loses electrons, while an anion forms when an atom gains electrons. An ionic bond is formed between oppositely charged ions, while a covalent bond is formed by the sharing of electrons between atoms.

Ions are formed when atoms gain or lose electrons. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence shell, and an anion (a negative ion) forms when a neutral atom gains one or more electrons in its valence shell. An example of a cation is sodium (Na+), which loses one electron to form a positive ion. An example of an anion is chloride (Cl-), which gains one electron to form a negative ion.

Difference between ionic and covalent bonds:

An ionic bond is formed by the attraction between a positive ion (cation) and a negative ion (anion). These ions are held together due to the opposite charges, similar to how oppositely charged magnets stick together. A covalent bond is formed when electrons are shared between two atoms. Each atom shares one of their electrons, which then orbits the nuclei of both atoms. Covalent bonds are typically formed between nonmetal atoms.

Answer:

Metals ionize by electron gain, non-metals ionize by electron loss while metalloids possess properties of both metals and non-metals

Explanation:

Answer:

a

Explanation:

Volume