how many significant figures are in the measurement 40,500 mg?

a) two
b) three
c) four
d) five​

Answer:

In this case, ethanol's molecular mass is 46 g/mol. This means that in 1 mol of ethanol, there are 46 g, thus the term molecular mass and molar mass are often used interchangeably. The same is true of a mole. A mole of anything is 6.022 x 1023 of that item

Explanation:

Answer:

9 moles of particles are present in 1 mole of ethyl alcohol.

Explanation:

1. Ethanol is ethyl alcohol with the chemical formula [tex]C_2H_5OH[/tex]

2. Molecular formula is given by [tex]C_2 H_6 O[/tex]

3. [tex]1 C_2 H_6 O_1[/tex]  

4. 1 represents 1 mole of ethyl alcohol

5. Subscripts represents the number of moles of each element.

6. 2 moles of carbon atoms,  6 moles of Hydrogen atoms and 1 mole of oxygen atoms are present in 1 mole of ethyl alcohol.

7. So, totally 9 moles of particles are present in 1 mole of ethyl alcohol

8. 1 mole contains [tex]6.022\times10^{23}[/tex] particles or atoms or molecules or ions  

9. For example 1 mole of [tex]H_2 O[/tex] contains [tex]6.022 \times 10^{23} H_2O[/tex] molecules (contains 2 moles of H and 1 mole of O atoms )

10. 1 mole of Na contains [tex]6.022 \times 10^{23}[/tex] Na atoms  

11. 1 mole of [tex]CaCO_3[/tex] contains [tex]6.022\times 10^{23}CaCO_3[/tex]  molecules (1 mole of Ca, 1mole of C and 3 moles of O atoms )

12. 1 mole of [tex]Na^+[/tex] contains [tex]6.022 \times 10^{23} Na^+[/tex] ions

Answer:

The sun will heat up and expand into a Red Giant star, then heat up to an extreme temperature, explode, and compact into an even hotter white dwarf star.

Explanation:

when our Sun runs out of hydrogen fuel, it will expand to become a red giant, puff off its outer layers, and then settle down as a compact white dwarf star, then slowly cooling down for trillions of years.

Answer:

White dwarf

Explanation:

Sun is a G-2 average mass star. It is 4.56 billion years old and would live for another 5 billion years. When the Sun would run out off fuel, its outer layers would expand and it will form a red giant star. The outer layers would eventually blow off into space and the remaining core would become a white dwarf. White dwarf is an electron degenerate star.

Lavoisier and Dobereiner  

I hope this helps!

Answer:

Lavoisier and Dobereiner is the correct answer.

Explanation:

To find the number of grams of O in 905 grams of Na2O, we calculate the molar mass of Na2O and O. Then, we use the ratio of moles of O to Na2O to calculate the number of moles of O. Finally, we multiply the number of moles of O by the molar mass of O to find the grams of O.

To calculate the number of grams of O in 905 grams of Na2O, we need to find the molar mass of Na2O and the molar mass of O. The molar mass of Na2O is 46 grams/mol (2*23 for Na + 16 for O) and the molar mass of O is 16 grams/mol.

In Na2O, there are 2 moles of Na for every 1 mole of O. So we can calculate the number of moles of O in 905 grams of Na2O by dividing 905 grams by the molar mass of Na2O, and then multiplying by the ratio of moles of O to moles of Na2O:

Number of moles of O = (905 grams Na2O / 46 grams/mol Na2O) * (1 mole O / 2 moles Na2O) = 9.85 moles O

Finally, we can calculate the number of grams of O by multiplying the number of moles of O by the molar mass of O:

Number of grams of O = 9.85 moles O * 16 grams/mol O = 157.6 grams O

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Answer:

K

Explanation:

The key aspect in this question is to look for Ionization Energy (EI), which describe the needed energy to take out an electron. Thefore, the potasiumm need lower energy . Another important thing is analyze how K will take nobel gas electron configuration when loss 1 electron, this It will be more stable

Answer:

Their similarity is that they have the same number of protons. Their difference is that they have different number of neutrons.

Explanation:

They are isotopes of the same element.

Answer:

Covalent bond

Explanation:

Covalent bond:

"The bond which is formed by the sharing of electrons between the atoms is called covalent bond"

The covalent bond is less stronger than ionic bond so require less energy to break as compared to the energy require to break the ionic bond.

The covalent bond is present between the oxygen molecule. It is the bond which is formed by the sharing of electrons between the two atoms of oxygen. Oxygen is present in group six of periodic table so there are six valance electrons are present. Oxygen molecules is formed by sharing the two valance electrons by each oxygen atom, thus double covalent bond is present in oxygen molecules. This is represented as O=O and two lone pairs are still present on each oxygen atom.

Answer:

two covalent bonds

Explanation:

Oxygen atoms can form two covalent bonds, so to link the two oxygen atoms together, a double bond forms between them.

Answer:

14.14

If you round it I'm guessing it would be 14.

Good luck <3

Answer:

10√2

Explanation:

Answer:

The reactivity of an element From left to right.

Explanation:

The most reactive are on the right while the least reactive elements towards the left.

He observed that the physical and chemical properties of elements were related to their atomic mass in a repeating or in a periodic manner.

Dmitri Ivanovich Mendeléev was a Russian chemist and perhaps the most important person who contributed to the early development of the periodic table. Many periodic tables were made before him but the most important one till then was the Mendeleev periodic table.

After the rejection of Newlands Octave Law, in 1869, Mendeleev's Periodic table came was bought into the picture. In Mendeleev’s periodic table, elements were arranged according to the fundamental property of their atomic mass, and chemical properties.

During Mendeleev’s work, there were only 63 elements that were known. After he finished studying the properties of every element, Mendeleev found that the properties of elements were related to atomic mass in a repeating or periodic manner. That is why he arranged the elements in a manner where the elements that had similar properties were in the same vertical columns of the periodic table.

Therefore, he observed that the physical and chemical properties of elements were relating to their atomic mass in a repeating or in a periodic manner.

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Answer:

They aren't physical properties of water because it's the chemical formula of water, H2o, or hydrogen and oxygen.

Explanation:

Examples of the physical property of water are Boiling Point, Freezing Point, Surface Tension, Heat of Vaporization, and Vapor Pressure, Viscosity, Cohesion, it's Solid, Liquid and Gas state.

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Answer:

The two reactants for photosynthesis are carbon dioxide (CO₂) and water (H₂O).

Explanation:

The equation for photosynthesis is as following:

6CO₂ + 6H₂O => C₆H₁₂O₆ + 6O₂

The reactants of a chemical reaction are the chemicals before the arrow, before the reaction takes place. In the equation above the reactants are carbon dioxide (CO₂) and water (H₂O).

Final answer:

Photosynthesis occurs in two stages: light-dependent reactions and the Calvin cycle. The light-dependent reactions convert sunlight into chemical energy and release oxygen. The Calvin cycle uses this energy to capture carbon and assemble sugar molecules.

Explanation:

Photosynthesis takes place in two stages: the light-dependent reactions and the Calvin cycle. In the light-dependent reactions, chlorophyll absorbs energy from sunlight and converts it into chemical energy with the aid of water. The light-dependent reactions release oxygen as a byproduct from the splitting of water. In the Calvin cycle, the chemical energy derived from the light-dependent reactions drives both the capture of carbon in carbon dioxide molecules and the subsequent assembly of sugar molecules.

Answer:

¹⁴N isotope

Explanation:

7p⁺  are representing the number of protons in the nucleus

7n° are representing the number of neutrons in the nucleus

7e⁻ are representing the number of electrons

If we add the number of protons and the number of neutrons we get a mass number of 14 which is the atomic mass of the nitrogen-14 isotope.

Answer:

N¹⁴

Explanation:

Each element has its own properties, and those properties can be seen by their atomic number and proton number. However, there are types of atoms called isotopes, and these atoms have a different number of neutrons compared to its standard atom. For example, the standard atom of carbon is carbon-12, however, there are isotopes of carbon that have more neutrons, making them heavier. Examples of such isotopes are carbon-13 and carbon-14.

In this question, we are looking for an atom with has 7 protons and 7 electrons. Scanning the periodic table of elements, we can see that nitrogen is the only atom with 7 protons, hence in a neutral atom of nitrogen, there are 7 protons and 7 electrons. The atomic mass can be calculated by adding the number of protons and the number of neutrons together, so the atomic mass for this isotope is:

Protons + Neutrons = Atomic Mass

= 7 + 7

= 14

The isotope represented by 7p+ 7e-, 7n0 is nitrogen-14 (N¹⁴).

Answer:

Heating a substance causes molecules to speed up and spread slightly further apart, occupying a larger volume that results in a decrease in density. ... Hot water is less dense and will float on room-temperature water. Cold water is more dense and will sink in room-temperature water.

Explanation:

Answer: it keeps the temperature more even

Explanation:

Answer: Decreased kinetic energy of the molecules

The first option that is given in the question is the correct option.

Explanation:

The molecules of a substance act differently at different temperatures but we know that its energy is dependent on the temperature at which it is present. The normal tendency of molecules is to vibrate on move around but, when it absorbs a certain amount of heat it gains more energy and tends to move around faster.

And just the other way round happens when heat is lost so we can say with a decrease in temperature the activity of molecules will also decrease and hence the kinetic energy will be decreased.

Answer:

Increase chemical energy of the molecules

Explanation:

Because once you change temperature it will have a chemistry reaction

Answer:

B. mass, volume

Explanation:

Density refers to a physical property that is measured using a ratio of mass divided by volume so that two objects of the same size can still have very different density.

Answer: Option (B) is the correct answer.

Explanation:

Density of a substance is defined as mass divided by its volume.

Mathematically,         Density = [tex]\frac{mass}{volume}[/tex]

So, density is proportional to the mass of substance. Hence, an increase in mass will lead to increase in density of the substance also.

Whereas density is inversely proportional to volume of a substance. Hence, an increase in volume will lead to a decrease in density of the substance.

Therefore, we can conclude that density refers to a physical property that is measured using a ratio of mass divided by volume so that two objects of the same size can still have very different density.

Answer:

20.3-17.5=2.8ml  1ml=1cm3   vol= 2.8cm3

Explanation:

The volume of the metal cube is calculated by subtracting the original volume of water in the cylinder (17.5 ml) from the volume after the cube was placed in the cylinder (20.3 ml), resulting in a cube volume of 2.8 cm³.

The volume of the metal cube that was placed in the graduated cylinder can be calculated from the change in water level. At the beginning, the cylinder contained 17.5 ml of water. When the metal cube was placed into the cylinder, the water level rose to 20.3 ml. The volume of the cube in cubic centimeters (cm³) or milliliters (ml), since 1 cm³ = 1 ml, can be determined simply by subtracting the original volume of water from the final volume.

So, the calculation is as follows: 20.3 ml - 17.5 ml = 2.8 cm³. Therefore, the volume of the metal cube is 2.8 cm³.

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Answer:

There will be produced 66g of CO2 if 45g of glucose completely reacted with oxygen

Explanation:

Step 1 : Balance the formula

Oxidation of glucose can be shown in the following equation :

C6H12O6  + 6 O2  → 6 CO2 + 6H2O

This means that for 1 mole glucose that react there will react 6 moles of O2, to form 6 moles of CO2 and 6 moles of H2O

Step 2: Calculating moles

mole glucose = 45g / Molar mass glucose

   ⇒ Molar mass = 6*12 + 12*1 + 6*16 = 72 + 12 + 96 = 180g/mole

⇒ mole glucose = 45g / 180g/mole

⇒mole glucose = 0.25 mole

Since 1 mole of glucose is used to form 6 moles of CO2

0.25 mole of glucose is used to form 1.5 moles of CO2

Step 3 : Calculating mass of Carbon dioxide

Mass of CO2 = 1.5 moles of CO2 * 44 g/mole

mass of CO2 = 66g

There will be produced 66g of CO2 if 45g of glucose completely reacted with oxygen

If 45g of glucose reacts with oxygen, 66.015 grams of carbon dioxide would be produced. This calculation is based on converting the mass of glucose to moles, using the stoichiometry of the balanced chemical equation, and then calculating the mass of CO2 produced.

When glucose (which has the chemical formula C6H12O6) is consumed, it reacts with oxygen to produce carbon dioxide, water, and energy. The chemical equation for this reaction is C6H12O6 + 6 O2 → 6 CO2 + 6 H2O. Given that 45g of C6H12O6 completely reacts with oxygen, we need to calculate the mass of carbon dioxide produced from this reaction.

To do this, we first need to determine the molar mass of glucose, which is 180.16 g/mol. This means that 1 mole of glucose weighs 180.16 grams. We can then find out how many moles of glucose 45g represents by dividing 45g by 180.16 g/mol, which gives us 0.25 mol of glucose.

According to the chemical equation, 1 mole of glucose produces 6 moles of CO2. Therefore, 0.25 moles of glucose would produce 0.25 × 6 = 1.5 moles of CO2. The molar mass of CO2 is 44.01 g/mol, so the mass of CO2 produced by 0.25 moles of glucose is 1.5 moles × 44.01 g/mol, resulting in 66.015 grams of CO2. So, if 45g of C6H12O6 completely reacted with oxygen, 66.015 grams of CO2 would be produced.

Some material from meteors lingers in the mesosphere, causing this layer to have a relatively high concentration of iron and other metal atoms. Very strange, high altitude clouds called "noctilucent clouds" or "polar mesospheric clouds" sometime form in the mesosphere near the poles.

I really hope this helps! I wish you the best of luck!

Answer:

m= 29.645 g

Explanation:

Density:

Density is equal to the mass of substance divided by its volume.

Units:

SI unit of density is Kg/m3.

Other units are given below,

g/cm3, g/mL , kg/L

Formula:

D=m/v

D= density

m=mass

V=volume

Symbol:

The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.

Given data:

density of wood = 0.77 g/cm³

volume= 38.5 cm³

mass= ?

Solution:

d= m/v

m= d × v

m= 0.77 g/cm³× 38.5 cm³

m= 29.645 g

Final answer:

The mass of a 38.5 cm3 piece of American white oak wood from the pile would be 29.645 g.

Explanation:

The density of American white oak wood is generally 0.77 g/cm³.

To calculate the mass of a 38.5 cm³ piece of wood from the pile, we can use the formula:

Mass = Density x Volume

Therefore, the mass of the wood would be: 0.77 g/cm³ x 38.5 cm³ = 29.645 g.

Answer:

V = 1.2 × 10⁻⁶ m³

Explanation:

Volume is equal to length × width × height, since we are given these measurements in the question we can simply plug our numbers into the formula.

V = l × w × h

V = 1.64 x 10⁻² × 1.5 x 10⁻² × 4.8 x 10⁻³

V = 1.2 × 10⁻⁶ m³

To calculate the volume of a salt crystal, multiply its three dimensions: 1.64 × 10^-2 m, 1.5 × 10^-2 m, and 4.8 × 10^-3 m. The resulting volume is 1.18 × 10^-6 cubic meters. This method uses basic multiplication of the crystal's dimensions.

Volume Calculation of a Salt Crystal

To find the volume of a salt crystal, you need to multiply its three dimensions together. The dimensions provided are 1.64 × 10-2 m, 1.5 × 10-2 m, and 4.8 × 10-3 m.

Here's the volume calculation step by step:

Volume = 1.64 × 10-2 m × 1.5 × 10-2 m × 4.8 × 10-3 m = 1.18 × 10-6 m3

Therefore, the volume of the salt crystal is 1.18 × 10-6 cubic meters.

Answer:

Chemical

Explanation:

Chemical changes are when a substance combines with another in order to form a new substance. In this instance the baking powder is reacting which creates carbon dioxide bubbles.

The release of carbon dioxide that results in the rising of bread is an example of a chemical change.

There is always a specific chemical or physical shift that goes along with changes in energy. A natural environment undergoes a variety of changes, including water evaporation, condensation, rainfall, and more. All of these modifications imply a change in state. Some reactions result in the breakdown of existing bonds in the reactants and the formation of new bonds in the products.

Chemical changes occur when the molecular makeup is totally changed and a new product is created. New products are created via chemical modifications. Chemical alterations are both permanent and irreversible.

It demonstrates that modifying or tweaking the experimental modifications cannot undo a chemical change. During a chemical reaction, the substance's mass changes. The mass is either added or subtracted.

Therefore the release of carbon dioxide that results in the rising of bread is an example of a chemical change.

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Answer:

Atomic Mass of Element = 59.57 amu

Given Data:

Element X Isotope 1 atomic weight = 59.015 amu  

Element X Isotope 2 atomic weight = 62.011 amu

The abundance of lighter isotope = 81.7%

Atomic Mass of Element X = ?

Solution:

81.7% is the abundance of element that is lighter so it is the of the isotope having weight 59.015 amu

Then the remaining abundance = 100 -81.7 = 18.3 %

18.3 % abundance of the isotope weight = 62.011 amu

Formula:

Mass of the element =  % of abundance (atomic mass of Isotope 1) + % of abundance (atomic mass of Isotope 2)

Put the values

Atomic mass of Element X = 81.7/100 (59.015) + 18.3 /100 (62.011)

Atomic mass of Element = 0.817 (59.015) + 0.183 (62.011)

Atomic mass of Element = 48.22 + 11.35

Atomic Mass of Element = 59.57 amu

Answer:

I think it is b) NOT SURE

Explanation:

Answer:

Atoms of different elements can combine with one another in simple whole number ratios

All the given statements are first proposed by John Dalton. But the one think that atoms are tiny indivisible particles had to be revised because of the discovery of subatomic particles electrons, protons and neutrons.

An atom is the basic unit of every substance in the universe. Atoms are made up of a nucleus and electrons. Nucleus is composed of positively charged protons and neutral particles neutrons.

There were many theories addressing the structure of atom in which the first significant one was Dalton's theory. According to this theory, Atoms are tiny indivisible particles.

The atoms of any one element are different from those of any other element. Compounds are made by combining atoms. Atoms of different elements can combine with one another in simple whole number ratios.

Later J.J thomson discovered electrons and Rutherford discovered protons and revolving nature of electrons around the nucleus. It was Niels Bohr who proposed the modern theory for atomic model and with the aid of this theory electronic properties of atoms were studied more.

Therefore, the indivisibility of atoms proposed by Dalton was wrong and thus option A is correct.

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Final answer:

Chemical properties of rocks include their ability to react with acids, undergo oxidation, and release substances under certain conditions; they define how rocks interact chemically with their environment.

Explanation:

Chemical Properties of Rocks

Chemical properties are characteristics of a substance that describe its potential to undergo certain chemical changes during reactions. In the context of rocks, these properties are crucial in understanding how they will interact with the environment. For instance, some common chemical properties of rocks include their reactivity with acids, ability to undergo oxidation, and potential to emit substances when exposed to various conditions.

Iron within rocks, for example, has the chemical property of reacting with oxygen and water to form rust, also known as iron oxide. This reaction is a form of corrosion and represents a significant chemical change. Another example is the reaction of calcite, a common mineral in limestone rocks, with acids; this results in the rock fizzing as carbon dioxide gas is released. Many rocks contain minerals that can react to cause a distinct chemical reaction, and identifying those reactions is essential for studying and classifying different rock types.

Answer:

Option C : Ag

Electronic configuration:

47Ag: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d9

The d-block elements are present in the middle of periodic table between s and p-block elements. d-block elements are also called Transition elements. Their valance electrons are reside in the d orbitals. They have more electropositive character than p-block elements but less than s- block elements.

Final answer:

The d block element among the given choices is Ag (silver), which is part of the second transition series, making the correct answer C) Ag.

Explanation:

The element that is a d block element among the choices provided is Ag (silver). This is because d block elements comprise the groups 3 through 12 on the periodic table, which are also known as the transition metals.

According to the division of the d block elements, silver (Ag) falls into the second transition series. S (sulfur) and Ar (argon) are p block elements, while As (arsenic) is also a p block element. Therefore, the correct answer is C) Ag.

Answer: False, True, True, True, True

Explanation:

Sound can travel through a vacuum.

False. Sound requires a medium (solid, liquid, or gas) to travel through. It cannot travel through a vacuum because there are no particles in a vacuum to transmit the sound waves.

Sound travels in longitudinal waves.

True. Sound waves are indeed longitudinal waves, which means the particles in the medium vibrate parallel to the direction of the wave.

Sound is caused by vibration.

True. Sound is produced by the vibration of particles in a medium, which creates compressions and rarefactions that propagate as sound waves.

Sound travels most slowly through a gas.

True. Sound generally travels more slowly through gases compared to liquids and solids because the particles in gases are more spread out, leading to a lower transmission speed.

Sound speeds up when the temperature is increased.

True. In general, the speed of sound increases with an increase in temperature. This is because an increase in temperature typically leads to an increase in the speed of the particles in the medium, allowing sound waves to propagate more quickly.

So, the correct statements are 2, 3, 4, and 5.

Answer:

In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic reaction, the opposite is true. The products have less stored chemical energy than the reactants. The excess energy in the reactants is released to the surroundings when the reaction occurs.

Explanation:

Final answer:

Energy released as light or thermal energy in a reaction is typically from exothermic chemical reactions, where more energy is released than required to break bonds. This occurs during the transformation of chemical potential energy into other energy forms such as heat or light.

Explanation:

The energy that can be released as light or thermal energy in a reaction is typically associated with chemical reactions. When the energy required to break the bonds in reactants is less than the energy released when new bonds form in products, the reaction is known as exothermic. Chemical energy, which is stored in the bonds of molecules, is a form of potential energy. During exothermic reactions, this energy is released as either heat or light, which can be observed, for example, as a flame on a kitchen burner fueled by natural gas. If the reaction absorbs more energy than it releases, it is called an endothermic reaction.

Final answer:

The percentage of ethylene glycol in the solution is calculated to be 34.21% by mass, which is obtained by dividing the mass of ethylene glycol by the total mass of the solution and then multiplying by 100.

Explanation:

The percentage of ethylene glycol in the solution can be calculated using the mass percentage formula, which is the mass of ethylene glycol divided by the total mass of the solution, then multiplied by 100 to convert it into a percentage. In this case, we have 130 g of ethylene glycol and a total solution mass of 380 g. The calculation would be:

Percentage of ethylene glycol = (Ethylene glycol mass / Total solution mass) × 100

Percentage of ethylene glycol = (130 g / 380 g) × 100

Percentage of ethylene glycol = 0.3421 × 100

Percentage of ethylene glycol = 34.21%

Therefore, the solution contains 34.21% ethylene glycol by mass.