6-8 , what does those symbols mean ?

Answer:

True

Explanation:

Its used to measure mass. Ten gallons weigh 8 pounds.

:D

Have a good day flopper :D

*eliza*

Answer:

false

Explanation:

weight and mass are very different your weight can change but your mass cannot so if you add 10 there isnt a difference in the mass

Answer:

4.98x10^-3 mole

Explanation:

According to Avogadro's hypothesis, 1 mole of any substance contains 6.02x10^23 atoms. This greatly implies that 1 mole of calcium will also contain 6.02x10^23 atoms.

Now, if 1 mole of calcium contains 6.02x10^23 atoms,

then Xmol of calcium will contain 3x10^21 atoms i.e

Xmol of calcium = 3x10^21/6.02x10^23

Xmol of calcium = 4.98x10^-3mol

Therefore, 4.98x10^-3 mole of calcium contains 3x10^21 atoms

3.00 × 10²¹ atoms of calcium are equivalent to 4.98 × 10⁻³ moles of calcium atoms.

To convert atoms to moles we need a conversion factor: Avogadro's number. According to Avogadro's number: there are 6.02 × 10²³ calcium atoms in 1 mole of calcium atoms. The number of moles corresponding to 3.00 × 10²¹ atoms of calcium are:

[tex]3.00 \times 10^{21} atoms \times \frac{1 mol}{6.02 \times 10^{23} atoms} = 4.98 \times 10^{-3} mol[/tex]

3.00 × 10²¹ atoms of calcium are equivalent to 4.98 × 10⁻³ moles of calcium atoms.

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Answer: 500L

Explanation:

No of moles= volume× molarity/1000

No of moles =0.5moles

Volume=?

Molarity of a gas at stp = 1M

Stp means standard temperature and pressure

No of moles = volume ×molarity/1000

Substitute the values

0.5=volume×1/1000

Cross multiply

Volume = 1000×0.5

Volume = 500L

The volume is 500L

Answer:

D)They can be formed from any of the three rock types, withstanding

high temperatures and pressures, and forming new minerals without

melting.

Explanation:

The metamorphic rocks are formed through cooling and hardening of magma or lava, both below Earth's surface or on Earth's surface as volcanic rocks. Thus the correct option is A.

The type of rock which are generated when rocks are subjected to many physical changes such as heat, pressure and different chemical reactivity over a long period of time are called metamorphic rocks.

The process of metamorphism makes the rocks as chemically modified and recrystallized. This process does not melt the rocks, but it transforms the rocks into dense and compact rocks.

The common metamorphic rocks are marble, schist, phyllite, etc. The action of pressure and temperature can even change the metamorphosed rocks into new types. They can be even folded and squished.

The term meta means change and morph means form. This rocks are formed as a result of geological process such as magma intrusions.

Thus the correct option is A.

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No of atoms in 4.8 dm³ of neon gas is determined in the following way.

Explanation:

We have given

Neon Gas=4.8dm³

At STP

1 mole of an ideal gas occupies 22.4 L(dm³) of volume.

which means that  number of molecules occupy 22.4 L of volume.

So

4.8 dm³x 1 mole/22.4 dm³ = 0.214 moles Neon

0.214 moles x 6.02x10²³ atoms/mole = 1.29x10²³ atoms of Neon

No of Atoms in 4.8dm3 neon gas =1.29x10²³ atoms of Neon

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Final answer:

To find the number of atoms in 4.8 dm³ of neon gas at rtp, we calculate the moles of neon and then multiply by Avogadro's number, resulting in approximately 1.29 x 10²³ atoms.

Explanation:

To calculate the number of atoms in 4.8 dm3 of neon gas at room temperature and pressure (rtp), we can use Avogadro's law which states that one mole of an ideal gas occupies 22.4 liters (or dm³) at rtp. Thus, to find the number of moles of neon gas, we divide the volume of the gas by the molar volume at rtp (22.4 dm3/mol).

Number of moles (n) = volume / molar volume = 4.8 dm3 / 22.4 dm³/mol = 0.214 moles

To find the number of atoms, we multiply the number of moles by Avogadro's number (6.022 x 10²³ atoms/mol).

Number of atoms = number of moles x Avogadro's number = 0.214 moles x 6.022 x  10²³atoms/mol = 1.29 x  10²³atoms

Therefore, there are approximately 1.29 x 10²³ neon atoms in 4.8 dm³ of neon gas at rtp.

Answer:

soe are appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many other

Explanation:

Answer: When a chemical reaction occurs, _____.

a phase change takes place

the physical and chemical properties of the products are different from the reactants

Explanation:

A chemical change is like dynamite exploding or iron rusting. It's an actual change in the chemical makeup resulting in a new product

A chemical reaction results in the production of new substances with physical and chemical properties that are different from the reactants, unlike a physical change which does not alter the molecular structure of the substance.

When a chemical reaction occurs, the physical and chemical properties of the products are different from the reactants. A chemical reaction involves a change in the composition of the substances in question where bonds between atoms are broken and/or formed, resulting in the production of new substances. These new products exhibit different physical and chemical properties such as melting point, color, taste, etc. This is in contrast to a physical change which only affects the appearance or form of a substance without altering its molecular structure. Chemical changes are often more difficult to reverse than physical changes. For example, combining hydrogen and oxygen to produce water is a chemical change because it results in the formation of a new substance with different properties than those of the individual reactants.

Answer:

7

Explanation:

Answer:

Bromine has 7 valence electrons.

Explanation:

Bromine is in group 7 or 17, so it has 7 valence electrons use the Lewis structure for more help.

Answer: P=1.63atm

Explanation:

Stp means standard temperature and pressure

Standard temperature =273k

Standard pressure =1atm

Using the formula

P1V1/T1=P2V2/T2

P1= 1atm

V1=5.23L

T1=273k

P2=?

V2=3.45L

T2=293k

Substitute the values

1×5.23/273=p2×3.45/293

Cross multiply

293×1×5.23=p2×3.45×273

1532.39=941.85p2

P2=1532.39/941.85

P2=1.627

P2=1.63atm

Answer:

3500 Calorie

Explanation:

Answer:

Explanation:

10 N right

Answer:

D

We don't have a way to contain the radioactive waste produced.

Explanation

Nuclear waste is non disposable and takes millions of years to biodegrade and lose it radio activeness

Answer:

Burning natural gas

Explanation:

hope this helps mark me as brainliest pls :)

Natural gas is a relatively clean burning fuel, meaning it produces less burning than oil or coal.

Methane makes up the majority of natural gas, which is a combination of gaseous hydrocarbons that also contains minor quantities of other higher alkanes. Typically, trace gases including helium, nitrogen, hydrogen sulfide, and carbon dioxide are also present in low concentrations.

When burning natural gas for energy, less carbon dioxide ( CO₂ ) and almost all other air pollutants are released into the atmosphere than when burning coal or petroleum products to provide the same amount of energy.

One of the cleanest and safest fuels is natural gas. In comparison to other fossil fuels, it produces less pollution. When natural gas is consumed, it mostly emits water vapor and carbon dioxide, which are also gases that people exhale.

Thus, Natural gas is a relatively clean burning fuel, meaning it produces less burning than oil or coal.

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Answer:

[tex]Q = 934.911\,kJ[/tex]

Explanation:

The energy needed to boil 17.3 moles of ice is:

[tex]Q = (17.3\,mol)\cdot \left[\left(40.5\,\frac{kJ}{mol} \right)+ \left(\frac{4.186}{1000}\,\frac{kJ}{g\cdot ^{\circ}C} \right)\cdot \left(\frac{18.015\,g }{1\,mol} \right)\cdot (100^{\circ}C-0^{\circ}C)+\left(6\,\frac{kJ}{mol}\right)\right][/tex][tex]Q = 934.911\,kJ[/tex]

Answer:

What are the options given?

Answer:They can be used over or 100 times without tear.

Explanation: A P E X

Answer : The balanced chemical reaction will be:

[tex]6Rb+Au_2O_3\rightarrow 2Au+3Rb_2O[/tex]

Explanation :

As per question, when rubidium react with gold oxide then it gives rubidium oxide and gold.

This reaction is a single replacement reaction in which more reactive element displaces the least react element from its solution.

The balanced chemical reaction will be:

[tex]6Rb+Au_2O_3\rightarrow 2Au+3Rb_2O[/tex]

Answer:

CCl4- tetrahedral bond angle 109°

PF3 - trigonal pyramidal bond angles less than 109°

OF2- Bent with bond angle much less than 109°

I3 - linear with bond angles = 180°

A molecule with two double bonds and no lone pairs - linear molecule with bond angle =180°

Explanation:

Valence shell electron-pair repulsion theory (VSEPR theory) helps us to predict the molecular shape, including bond angles around a central atom, of a molecule by examination of the number of bonds and lone electron pairs in its Lewis structure. The VSEPR model assumes that electron pairs in the valence shell of a central atom will adopt an arrangement which tends to minimize repulsions between these electron pairs by maximizing the distance between them. The electrons in the valence shell of a central atom are either bonding pairs of electrons, located primarily between bonded atoms, or lone pairs. The electrostatic repulsion of these electrons is reduced when the various regions of high electron density assume positions as far apart from each other as possible.

Lone pairs and multiple bonds are known to cause more repulsion than single bonds and bond pairs. Hence the presence of lone pairs or multiple bonds tend to distort the molecular geometry geometry away from that predicted on the basis of VSEPR theory. For instance CCl4 is tetrahedral with no lone pair and four regions of electron density around the central atom. This is the expected geometry. However OF2 also has four regions of electron density but has a bent structure. The molecule has four regions of electron density but two of them are lone pairs causing more repulsion. Hence the observed bond angle is less than 109°.

Answer:

D, because he discovered electrons

Explanation:

His results gave the first evidence that atoms were made up of smaller particles.

Answer:

0.08 g

Explanation:

100.0 mL = 0.10 L

Multiply the volume by the molarity to find moles.

0.10 L × 0.20 M = 0.002 mol

Convert moles to grams.

0.002 mol × 40 g/mol = 0.08 g

Final answer:

To prepare 100.0 mL of 0.20M NaOH solution, a student needs to weigh out 0.80 grams of NaOH, using the molar mass of NaOH and the desired solution volume and concentration.

Explanation:

Calculating the Mass of NaOH Needed for 0.20M Solution

To determine the mass of sodium hydroxide (NaOH) necessary to prepare a 100.0 mL of 0.20M NaOH solution, we have to follow multiple steps:

Calculate the number of moles of NaOH required using the formula Molarity (M) = Moles of solute (mol) / Volume of solution in liters (L).

Convert the volume from mL to L, since the molarity formula requires volume in liters.

Use the molar mass of NaOH to convert moles to grams.

First, we calculate the moles needed:

0.20 mol/L * 0.100 L = 0.020 mol NaOH

Next, we determine the mass of NaOH using its molar mass:

Molar mass of NaOH = 40.00 g/mol

Mass of NaOH = Moles * Molar mass

Mass of NaOH = 0.020 mol * 40.00 g/mol = 0.80 g NaOH

Therefore, the student would need to weigh out 0.80 grams of NaOH to prepare a 100.0 mL of 0.20M NaOH solution.

Answer:

Temperature of water is 40

Reaction Time is 26.3

Explanation:

Hope this helps

A reaction's rate can be used as a valuable diagnostic tool. The temperature of water is 40° C, and the rate of reaction is 26.3.

The speed at which a chemical reaction occurs is known as the reaction rate or rate of reaction. It is proportional to the rise in product concentration per unit time and the fall in reactant concentration per unit time. Reaction times might differ significantly.

We may devise strategies to increase production by learning how quickly things are created and what slows down reactions. This knowledge is necessary for the industrial production of various chemicals, such as fertilizers, medications, and home cleaners.

The change in a reactant or product's concentration over time is what is referred to as the rate of a chemical reaction. Concentration is measured in moles per liter, or molar, and time is measured in seconds. Therefore, we use molar per second to indicate the pace of a chemical reaction.

Thus, the temperature of water is 40° C, and the rate of reaction is 26.3.

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Answer:

27.56 moles

Explanation:

Answer:

27.56 mol ans C)

Explanation:

Answer:

It is made of atoms that are covalently bonded together.

Explanation:

For example the carbonate ion CO3++.

The carbon and oxygen atoms are held together by covalent bonds.

Answer:

"It is made of atoms that are covalently bonded together." (C)

Explanation:

Polyatomic ion is made of three atoms that are covalently bonded together

Edg. 2020 :)

Answer:

see below

Explanation:

Hydrogen reacting with oxygen to generate water produces a relatively large amount of thermal energy. As requested and in terms of bonding energies, a Hydrogen - Oxygen fuel cell reaction could be illustrated as follows...

                     H - H              +           1/2(O = O)              =>           H - O - H

ΔHb:     1mol(-436Kj/mol)          1/2mol(498 Kj/mol)               1mol(-463 Kj/mol)

              = -436Kj                             = -249Kj                               = -926Kj

ΔH(Rxn) =  ∑ΔH(Products) - ∑ΔH(reactants)

=  [(-926kj)] - [(-436Kj) + (-249Kj)]

= (-926 + 436 + 249)Kj = -241Kj (=> which is the Standard Heat of Formation of Water => See Thermo Tables in text appendix).

This means, on reaction of Hydrogen and Oxygen, 241Kj energy is released by exothermic process. The challenge now, is to direct this 241Kj of energy into a material substance so as to generate useful outcomes (work).      

Now one should understand that the source of the energy in this problem is from the hydrogen - oxygen reaction, however, there are other mechanisms and reactions that generate thermal energy. Hydrogen fuel cell is but one.

So, now what does one do with the thermal energy generated in the fuel cell reaction. That is, what application would be needing 241Kj of energy per mole water formed? Consider two needed (hypothetical) applications    => 1. to boil water and the other 2. to warm a tub of bathwater.          

Our physics friends tell us that the amount of thermal heat used is related to the mass of substance receiving the heat and the resulting temperature change accompanying the transfer of thermal energy by the following equation ...

q = mcΔT where q = thermal energy. m = mass, c = specific heat & ΔT = Temperature change.

Given that both applications will receive the same amount of thermal energy ( => 241Kj) the question is reduced to how much mass would be needed to heat the water to boiling for application 1 vs amount of water to moderately heat water for a bath.          

Application 1 (Boiling water)  => 241Kj energy would only need a small quantity of water to achieve a high enough temperature to reach boiling point where as, Application 2 (Warming bath water) => 241Kj energy would be applied to a much larger quantity of water to limit the heating effect to a  moderate temperature level.

In summary, the hydrogen-oxygen fuel cell reaction produces thermal energy => the thermal energy is directed into a mass of substance that is then heated to a needed temperature level to perform a functional service.  The services derived from the H/Oxy rxn are, in essence, the utility of the process as a fuel. :-)        

Addendum => The Hydrogen Electrochemical fuel cell process is the same except the process is galvanic in nature but still generates the same amount of thermal energy which is translated directly into electrical energy for needed applications.