can somebody help with this please ?

Answer:

Explanation:

7gN2 x [tex]\frac{1 mol}{2(14.01) g}[/tex]

=0.2498mol N2

Nitrogen gas has the formula [tex]N_{2}[/tex] so therefore that means you would have to multiply the mass in the molar by 2. To solve for the number of moles you need to cancel out the grams, you do this by using the molar mass of nitrgoen gas. You get the value on in the denominator from the periodic table (atomic mass of element). The grams will cancel out, leaving you with the number of moles when you divide 7/2(14.01).

Answer:

0.354L

Explanation:

Given parameters:

Molarity of KCN  = 0.025M

Number of moles  = 8.84 x 10⁻³mol

Unknown:

Volume of KCN  = ?

Solution:

The molarity of a substance is expressed as;

       Molarity  = [tex]\frac{number of moles }{volume }[/tex]  

 Volume of KCN   = [tex]\frac{number of moles }{molarity}[/tex]

Now insert the parameters and solve;

  Volume of KCN  = [tex]\frac{0.00884}{0.025}[/tex]   = 0.354L

heres your answer mate...

Answer:

500g

Explanation:

Just divide by all the numbers and the one that equals 1.6 is the answer

Answer:

58.5g/mol

Explanation:

Given substance:

 Sodium chloride  = NaCl

Unknown:

Molecular mass = ?

Solution:

The molecular mass of a compound is the gram-formula mass or gram-molecular weight of the compound.

It is determined by adding its component atomic masses and then express in grams per mole;

Atomic mass of Na = 23g

Atomic mass of Cl = 35.5g

 NaCl  = 23 + 35.5  = 58.5g/mol

To solve this we must be knowing each and every concept related to satellite. Therefore,  moon phases and moon placements have a role the appearance of the moon from earth.

Any object that circles a planet in a curved route is considered a satellite. There are several man-made (manufactured) satellites, most of which are closer to Earth than the moon, which is Earth's original natural satellite.

We must revisit our buddy Newton in order to comprehend why satellites move in this manner. Gravity, according to Newton, is a force that unites all of the universe's objects. Moon phases and moon placements have a role in determining this. The only major factor affecting the Moon's phase is where it is in relation to Earth and the Sun.

Therefore,  moon phases and moon placements have a role the appearance of the moon from earth.

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Answer:

All the above

Explanation:

All the above

Answer:

A.  I and II only

Explanation:

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.

As the size of atom increases the ionization energy from top to bottom also  decreases because it becomes easier to remove the electron because of less nuclear attraction and as more electrons are added the outer electrons becomes more shielded and away from nucleus.

Melting point also goes to decreases because there is large distance between the positive nucleus and bonded electrons thus overall attraction goes to reduced and less energy is required to melt.

Answer:

The molecules experienced a physical change from a solid state to a gaseous state, which increased the molecular movement and the energy of the carbon dioxide molecules

brainliest

The statement which best describes the change in the energy and physical characteristics of the molecules of carbon dioxide during this process is (B) The molecules experienced a chemical change as the carbon dioxide reacted with oxygen, which released oxygen gas into the environment and increased the molecular movement.Hence, The correct option is (B)

Physical changes are those that affect a chemical substance's form but not its chemical content.

Physical changes may normally be used to separate compounds into chemical elements or simpler compounds, but they cannot be used to separate mixtures into their component compounds.

A change in physical attributes accompanies a physical change. Melting, turning into a gas, and changing strength are a few examples of physical qualities.

Therefore, molecules of carbon dioxide during this process is (B) The molecules experienced a chemical change as the carbon dioxide reacted with oxygen, which released oxygen gas into the environment and increased the molecular movement.Hence, The correct option is (B)

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Answer:

An endothermic process is any process with an increase in the enthalpy H (or internal energy U) of the system. In such a process, a closed system usually absorbs thermal energy from its surroundings, which is heat transfer into the system.

Several erosive agents affect the soil structure and composition. Selecting sandstone, 100cm/yr precipitation, 20ºC, and 50% vegetation cover, there is 45% of eroded rock. The general landscape appearance changes little.

Erosion is the process of fertile soil loss.

It is due to several external agents that damage the ground and drag the exposed material from the superficial layer of the earth.

Some of the erosive agents are water, wind, ice, gravity, or animal trampling.

Three main phases compose the erosion process

a) particles landslide

b) transport of superficial free particles

c) deposit/sedimentation.

Soil erosion leads to its degradation.

Since its regeneration is extremely slow, erosion produces several negative events that lead to soil loss as a non-renewable natural resource.

All the erosive agents act together modifying the soil composition, shape, and structure. The loss of plant cover increases, even more, the erosive effects.

Soil vegetation cover reduces erosion because the aerial part of the plant protects the surface, while roots protect the ground structure and retain water.

The less vegetation cover there is, the more exposed the soil is, and the more severe effects the erosive agents cause.

In the exposed example, we have many variables to control and analyze their effect on soil erosion. Before playing the simulation, I chose the followings

Under these conditions, after 20,000 years there was 0.42 km³ of eroded rock.

The general aspect of the landscape changed very little, suggesting that erosion occurs slowly.

Probably, if we change the values of the variables, we will observe a sharper change. For instance, if we take the vegetable cover to less than 20% and increase the levels of precipitation and temperature, we will observe a faster erosion process and a wider affected area.

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Answer:

the correct answer in energy

Explanation:

The term refers to the ability to do work is energy. The correct option is A.

Energy is the quantitative property that is required by the body to do some work. It is a conserved quantity, but can not be created or destroyed.

Animals and plants get energy from food.

Thus, the correct option is A. energy.

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[tex]\mathrm {Hey, there!}[/tex]

The answer is: Bromine

Oxygen is not similar to flourine, it is not a noble gas with high ionization.

Neon does not have chemical reactions like flourine.

The answer is Bromine! Best of Luck!

Answer:

Br

Explanation:

Answer:

Covalent bonding

Explanation:

covalent bonding

Answer:

E = 3.81×10 ⁻²¹ J

Explanation:

Given data:

Frequency of photon = 5.75 ×10¹² Hz

Plancks constant = 6.626 ×10⁻³⁴ Js

Energy of photon = ?

Solution:

E = h×f

E = 6.626 ×10⁻³⁴ Js ×  5.75 ×10¹² s⁻¹

E = 38.1×10 ⁻²² J

E = 3.81×10 ⁻²¹ J

Explanation:

Density is an intensive property of any matter. Any given pure sample of a substance will have the same density value.

Density is the mass per unit volume of a compound;

  Mathematically;

    D = [tex]\frac{M}{V}[/tex]  

where M is the mass

          V is the volume

          D is the density

Answer:

When atoms are excited they emit light of certain wavelengths which correspond to different colors. Each element produces a unique set of spectral lines. Since no two elements emit the same spectral lines, elements can be identified by their line spectrum.

Explanation:

Answer:

The final temperature is 566°K

Explanation:

Given

V1 = 0.444L

T1 = 0.00°C

P1 = 79.00 kPa

V2 = 1880mL

P2 = 38.70 kPa

Required

Determine the final temperature of the gas

To answer this, we make use of idea gas law equation.

This is:

(P1V1)/T1 = (P2V2)/T2

Convert V1 to mL

V1 = 0.444L

V1 = 0.444 * 1000mL

V1 = 444mL

Convert T1 to Kelvin

T1 = 0.00°C

T1 = 0.00 + 273K

T1 = 273K

Substitute these values in the given equation.

(P1V1)/T1 = (P2V2)/T2

(79 * 444)/273 = (38.70 * 1880)/T2

35076/273 = 72756/T2

Cross Multiply

35076 * T2 = 273 * 72756

35076T2 = 19862388

Make T2 the subject

T2 = 19862388 ÷ 35076

T2 = 566K (approximated)

Hence, the final temperature is 566°K

Explanation:

1. Sedimentation and decantation cannot be used for all types of mixtures.

Decantation is a separation technique in which is used to separate immiscible liquids or mixtures containing liquid and solids within them.

In decantation, gravity is used to bring the denser materials to settle at the bottom.

For homogenous mixtures, it is not possible to use decantation. A solution of sugar and water will not decant.

2. Yes, mass of an object reduces the settling time of such object in a mixture.

The higher the mass, the faster the rate of settling. Also, as we know, mass is directly proportional to density. A body with a high density will settle faster in solution.

Answer:

1. Chemical reactions

2.Substances

3. Properties

4. Precipitate

5. Light

6. Temperature

7. Color

8. Gas

Explanation:

During chemical reactions, new substances that possess new properties are formed. During the process of chemical reactions, evidences are found. Some of the evidences are formation of precipitate or light gel, production of gases and changes in colour and temperature.

Chemical reactions start with the substances or compounds which are known as reactants. The reactants react to form new substances known as the products which possess new properties.

Answer:

pH = 11.9

Explanation:

First, we determine the number of OH⁻ moles dissolved:

80% of Ca(OH)₂ is dissolved:

There are two OH⁻ moles per Ca(OH)₂ mol:

Now we can calculate the molar concentration of OH⁻ (moles/L):

Then we calculate the pOH of the solution:

Finally, we can calculate the pH of the solution using the equation

Answer:

A

Explanation:

Answer:

n = 24 waves

Explanation:

As, the sound is produced with a steady pitch. Therefore, it means that there is no change in the pitch with respect to time. Hence, we can work with the following formula for frequency:

υ = n/t

where,

υ = frequency of sound wave = 6 waves/s

n = no. of waves = ?

t = time interval = 4 s

Therefore, using these values in the equation we get:

6 waves/s = n/4 s

n = (6 waves/s)(4 s)

n = 24 waves

Answer:

See explanation

Explanation:

According to the second law of thermodynamics, the conversion of energy  from one form to another is never hundred percent efficient. Some energy is always lost as energy is transformed from one form to another.

When a fuel is used to run an automobile engine, chemical energy from the fuel is converted into to the mechanical energy of the automobile. This energy conversion can never be hundred percent efficient in accordance with the laws of thermodynamics. Some energy is always lost as heat.

Hence, the engine does not even efficiently convert all the chemical energy available in the fuel. Therefore, it is impossible to find an automobile engine that can produce more energy than the fuel used to run it.

Answer:

It is false :l

Explanation:

Pahoehoe is a smooth and continuous lava crust. Pahoehoe forms when the effusion rate is low and consequently the velocity of lava flow is slow. Pahoehoe lava flow is usually at least 10 times slower than typical aa lava flow.

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Answer:

please give the answer choice.

Answer:

A) Km

B) m

C) cm

D) mm

Explanation:

A) The distance between Chicago and Saint Louis is quite a distance and would be best presented in the largest multiple of the SI unit of length.

For example if the distance is 500000 m, it's a bit bogus to write, so we can simplify by writing in terms of 10^(-3) m which is in km.

Thus, we can write as 500000 × 10^(-3) km = 500 km

B) By standard measurement, the size of a bedroom is usually: 3.6 m × 3.6 m.

This not complex to write and can be kept as it is in metres.

C) The average dimension of a textbook is around 0.25 m by 0.2 m.

Let's get rid of the decimal by converting to terms of 10² m which is expressed as cm.

Thus, dimension is now: (0.25 × 10²) by (0.2 × 10²) = 25 cm by 20 cm

D) Average thickness of a hair in metres is 8 × 10^(-5) m.

Now this is a bit long. So we can express is in terms of 10^(3) m which is an expression denoted by millimeter (mm).

Thus, thickness is 8 × 10^(-5) × 10³ = 0.08 mm

Answer:

D

Explanation: