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Please i need help with these questions.
Please show workings.​

Answer:

A

Explanation:

Answer:

It is A!

Explanation:

Answer:

2 8 8 8 8 1

Explanation:

Answer:

force

Explanation:

because the force

Given the balanced equation:

( Reaction type : double replacement)

CaF2 + H2SO4 → CaSO4 + 2HFI

We can determine the number of grams prepared from the quantity of 75.0 H2SO4, and 63.0g of CaF2 by converting these grams to moles per substance.

This can be done by evaluating the atomic mass of each element of the substance, and totaling it to find the molecular mass.

For H2SO4 or hydrogen sulfate it's molecular mass is the sum of the quantity of atomic mass per element. H×2 + S×1 + O×4 = ≈1.01×2 + ≈32.06×1 + ≈16×4 = 2.02 + 32.06 + 64 = 98.08 u (Dalton's or Da) or g / mol.

For CaF2 or calcium fluoride, it's molecular mass adds 1 atomic mass of calcium and 2 atomic masses of fluoride due to the number of atoms.

Ca×1 + F×2 = ≈40.07×1 + ≈19×2 = 40.08 + 38 = 78.07 u (Da or Dalton's) or g / mol.

The limiting  reactant in the given balanced reaction is sulphuric acid. The mass of HF produced from 75 g of H₂SO₄ is 30 g.

The limiting reactant in a species is the reactant which is fewer in amount and thus determine the yield of the product.

In the given reaction, one mole of calcium fluoride reacts with one mole of sulphuric acid to give two moles of HF. The molar mass of calcium fluoride CaF₂ is 78 g/mol the weight taken here is 63 g. Thus number of moles is 63/78 = 0.87 moles.

The molar mass of sulphuric acid H₂SO₄ is 100g/mol. The weight taken here is 75 g and thus, number of moles is 75/100 = 0.75 moles. One mole of calcium fluoride need one mole of H₂SO₄ . Thus 0.87 neede 0.87 moles of H₂SO₄ . But here we have only 0.75. Thus it is the limiting reactant.

As per the reaction, one mole or 100 g of H₂SO₄  produce 2 moles or 40 g of HF (molar mass = 20 g/mol). Thus mass of HF produced from 75 g is calculated as follows:

mass of HF = (75 × 40)/100

                   =  30 g.

Hence, mass of HF produced in this reaction is 30 g.

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Answer:

Each parent's half of the genes acquired  by the offspring. They  have two of each chromosome and hence two alleles of each gene, and one acquired from each parent.

Answer:

2.Diffusion

Explanation:

As we metabolize certain nutrients for the correct functioning of our cells, carbon dioxide is produced as a result. We need oxygen in order to metabolize them, so we need to have a system to incorporate it, and to eliminate the carbon dioxide produced.

This system is provided by the interaction between the respiratory system, which allows the enter of oxygen into the body and gets rid of the carbon dioxide, and the circulatory system, which acts transporting carbon dioxide and oxygen to and from the lungs, respectively.

The surface available for the gaseous exchange is enlarged by the pulmonary alveoli. The alveoli are the terminal aerial spaces of the respiratory system and the structures where the exchange between the air and blood is produced. Each alveolus is surrounded by a net of capillaries, where oxygen is freed from the hemoglobin and moves into the cells by diffusion. Carbon dioxide, diffuses out of the cells into the capillaries, where most of it dissolves in the plasma of the blood.

Answer:

0.010g of C-14 would be later after 50,000 years

Explanation:

The kinetics of radioactive decay follows the equation:

Ln (N / N₀) = -kt

Where N could be taken as mass after time t,

N₀ initial mass = 4.30g;

k is rate constant = ln 2 / t(1/2)

= ln 2 / 5730years = 1.2097x10⁻⁴ years ⁻¹

Replacing:

Ln (N / 4.30g) = -1.2097x10⁻⁴ years ⁻¹ * 50000 years

N / 4.30 = 2.36x10⁻³

N =

Answer:

Wind is the horizontal movement of air, transporting energy transferred from the earth's surface as sensible and latent heat. Sensible heat is transferred by the processes of conduction and convection. Conduction transfers energy within a substance, and convection transfers energy through the vertical movement of the heated substance. Latent heat is the transfer of energy by transforming the substance itself. As you recall, water has the ability to exist as liquid, gas or solid. The transformation from liquid to gas is called evaporation; the reverse process, from gas to liquid, is called condensation; from liquid to solid is known as solidification (freezing); and from solid to liquid, fusion (melting). Water can also be transformed directly from solid to gas (sublimation), or the reverse, through a process called deposition. We will see these various processes in the formation of clouds.

Explanation:

if I did not give answer then i hope i at least helped!

Noble gas configuration for Li : [He]2s¹

In an atom, there are levels of energy in the shell and sub-shell

This energy level is expressed in the form of electron configurations.

Lithium with atomic number 3, then the electron configuration:

1s²2s¹

And for noble gas configuration or it can be called Condensed electron configurations :

[He]2s¹

Answer:

[He]2s¹

Explanation:

Answer:

P(Kr) = 1.2 atm

Explanation:

According to Dalton law of partial pressure,

The total pressure inside container is equal to the sum of partial pressures of individual gases present in container.

Mathematical expression:

P(total) = P₁ + P₂ + P₃+ ............+Pₙ

Now we will solve this  problem by using this law

Total pressure = 1.60 atm

Partial pressure of neon = 0.40 atm

Partial pressure of krypton = ?

Solution:

P(total) = P(Ne)+ P(Kr)

1.60 atm = 0.40 atm +P(Kr)

P(Kr) = 1.60 atm -  0.40 atm

P(Kr) = 1.2 atm

The partial pressure of Krypton in the mixture has been 1.2 atm.

Partial pressure can be defined as the pressure exerted by a single gas in the solution.

According to Dalton’s law of partial pressure, the total pressure of the gas has been the summation of the partial pressure of each gas present in the mixture.

Total pressure = Partial pressure of A + Partial pressure of B + Partial pressure of C……

The given mixture has been consisted of neon and krypton. The total pressure of the mixture has been:

Total pressure = Partial pressure of Ne + Partial pressure of Kr

The total pressure = 1.60 atm.

The partial pressure of Ne = 0.40 atm.

Substituting the values:

1.60 atm = 0.40 atm + Partial pressure of Kr

Partial pressure of Kr = 1.60 - 0.40 atm

Partial pressure of Kr = 1.2 atm.

The partial pressure of Krypton in the mixture has been 1.2 atm.

For more information about the partial pressure, refer to the link:

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Answer & Explanation:

Susana's red crystal sample is a compound because it was broken down into a gas and blue powder. It is not an element because elements cannot be broken down into simpler substances by ordinary means, such as heating.

Answer:

Susana's red crystal sample is a compound because it was broken down into a gas and blue powder. It is not an element because elements cannot be broken down into simpler substances by ordinary means, such as heating.

Explanation

Sample response form Edg

Answer:

An atom that has a negative or positive charge it is called an ion.

Answer:

It''s called a Cation

Explanation:

Answer:

D

Explanation:

The high jump of ionization energy indicates that we are trying to remove electron from noble gas configuration state.

The ionization energy data specifies that the Elements are from group 1 at period 3 or greater.

Removing the first electron require 496 kJ and the second ionization energy jump significantly due to the removal of electron from the noble gas configuration which is logical because electron try to maintain the especially stable state.

Answer: the density of the rock

55.91g/ml

Explanation:

The density of the rock after it had being placed in the cylinder of water so the calculation should look like this:

Volume of water substract the mass of the rock:

And that is 142.5 ml - 86.59g =

Answer 55.91 g/ml

So the density of the rock is 55.91g/ml

The initial temperature of the metal = 35 °C

Heat can be formulated :

Q = m . c . ΔT

Q = heat, J

c = specific heat, J/g C

ΔT = temperature, °C

m = 20 g

c = 5 J/(g°C)

Q = 500 J

T₁ = 40 C

the initial temperature :

[tex]\tt \Delta t(T_2-T_1)=\dfrac{Q}{m.c}\\\\40-T_1=\dfrac{500}{20.5}\\\\40-T_1=5\\\\T_1=35^oC[/tex]

Answer: D

Explanation: trust

Answer:

Explanation:

D

Answer:

Transition Metals

Explanation:

Hope this helped :)

Answer: Jason experiment

Explanation:

I just took the test

Answer: Jason's Experiment

A.conduction  i hope it helps

Answer:

conduction

Explanation:

here is what came up when i searched it up:

"The attraction between protons and electrons can also make clothes stick together in the dryer. When you dry clothes in the dryer, different fabrics rub together, and electrons from a cotton sock (for instance) may rub off onto a polyester shirt."

Sometimes, clothes can get stuck together after they come out of a dryer because of static electricity.

No, clothes may not start off as neutral. Whether clothes have static charges before going into the dryer depends on different things.

Static electricity happens when certain things touch and create an uneven amount of electrons. This can cause one material to have a positive charge and the other to have a negative charge. When clothes move and touch each other in a dryer, this rubbing can cause static electricity.

If the clothes are cleaned and dried correctly, they should have no charge or be evenly charged.

Read more about  clothes  here:

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Answer:

-320f

Explanation:

Answer:

Option B and D seem to be correct

Explanation:

As a scientific law is a statement which is bases on repeated experimental observations that describes some aspects of nature and also  they are were theories that have been proven to be true as a theory become a law when the experiment agree with the theory and no contrary opinions so according to my studies , B and D options are seems to be correct.