I’ve missed this question twice now. Please help

Answer:

Explanation:

C

[tex]4.9 \times 10^{23}[/tex]  are present in 18.4L of argon (Ar).

To calculate the amount of particles present in a given amount of volume, it is necessary to have knowledge of the molar volume:

                                          [tex]1 mol = 22.4L[/tex]

Thus, in 22.4L there is 1 mol of an element, remembering that:

                                   [tex]1 mol = 6\times10^{23}[/tex] particles

In this way, it is enough to relate the value of the molar volume given with the value requested by the question:

                                     [tex]\frac{6\times10^{23}particles}{xparticles} = \frac{22.4L}{18.4L}[/tex]

                                    [tex]x = 4.9 \times 10^{23}[/tex] particles

 So, [tex]4.9 \times 10^{23}[/tex] are present in 18.4L of argon (Ar).

Learn more about mole calculation in: brainly.com/question/15209553

Firework mixture is made up with potassium nitrate and other toxic chemicals. They produce harmful wastes to the atmosphere. If they are contaminated, they make release very dangerous explosives by unwanted reactions.

Explosives are chemicals releasing lot of heat energy to the surrounding upon  decomposition. Nitrogen compounds, hydrogen etc are explosive and they will explode in air or water.

Chemicals have to handled carefully and stored as per the conditions based on their chemical and physical properties. Some of them may easily corrode. Some may rapidly reacts with water or air and some may explode in air.

Explosive chemicals causes atmospheric pollution as well as health risk by releasing hazardous chemicals. If they are contaminated then there may occur some unwanted reaction and it will make the risk intense by producing toxic gases.

To find more about explosives, refer here:

https://brainly.com/question/8735140

#SPJ2

Answer:

Disease ranching

Explanation:

Floods and Droughts are caused by the enviorment. Diseases are but a product and don't  affect the enviorment.

Answer:

disease ranching is not a natural change to the environment .

Explanation:

This all happen because of human activities

Answer:

The protic solvents are (CH3)2CHOH, NH3, and HCONH2

The aprotic solvent are CH3NO2, CH2Cl2, and N(CH3)3

Explanation:

A protic solvent is a solvent that has a hydrogen atom bound to an oxygen (O), a nitrogen (N), or fluoride (F). Generally, any solvent that contains a labile H⁺ is called a protic solvent.

a. (CH3)2CHOH

(CH3)2CHOH is a protic solvent because one of the hydrogens is bound to oxygen (O)

b. CH3NO2

CH3NO2 is an aprotic (i.e not a protic solvent) solvent because all the hydrogens are bound to carbon.

c. CH2Cl2

CH2Cl2 is an aprotic solvent because all the hydrogens are bound to carbon.

d. NH3 is a protic solvent because all the hydrogens are bound to Nitrogen (N)

e. N(CH3)3 is an aprotic solvent because all the hydrogens are bound to carbon

f. HCONH2 is a protic solvent because two of the hydrogens are bound to Nitrogen (N)

290 g Na₂O

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Step 1: Define

4.7 mol Na₂O

Step 2: Identify Conversions

Molar Mass of Na - 22.99 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of Na₂O - 2(22.99) + 16.00 = 61.98 g/mol

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 2 sig figs.

291.306 g Na₂O ≈ 290 g Na₂O

4.2 × 10⁻²¹ moles Sn

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Step 1: Define

2500 atoms Sn

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 2 sig figs.

4.15144 × 10⁻²¹ moles Sn ≈ 4.2 × 10⁻²¹ moles Sn

Answer:

It is refracted out, B

Explanation:

When the light travels through the prism, it refracts the colors out of it. In which a rainbow sort coloration is released from the other side.

Answer:

Explanation:

Refraction of light waves

Answer:

0.67 g

Explanation:

We know that 1 mole of an element is 6.02 x 10^(23) atoms

Now, arsenic has 5.49 × 10²¹ atoms

Thus;

Number of moles of arsenic = 5.49 × 10²¹ × 1/6.02 x 10^(23) = 9 × 10^(-3) moles

We are told that;

one mole of arsenic = 74.92 g.

Thus, 9 × 10^(-3) moles = 9 × 10^(-3) × 74.92/1 = 0.67428 g ≈ 0.67 g

Answer:

It would cause scattering of light and absorbance measurement is going to be reported as too large

Explanation:

The curvette was not inserted correctly into the spectrometer. The effect that this would have on measured absorbance is that it would cause scattering of light.

Failing to line the curvette correctly would cause light to scatter, the light reaching the photodetector would be less. This less light would then be interpreted as more light being absorbed. This would end up making the absorbance value to be read as too large.

Answer:

1=a 2=d i think

Explanation:

Answer:

ptic fiber communication and satellite communication are the leading technologies which are revolutionizing the world of telecommunications. Both technologies have their advantages and limitations which make them suitable for certain type of applications. This article will provide an overview of optic fiber and satellite communication technologies and present a comparison of the features and related issues.

Optic Fiber Communication

Optic Fiber communication transmits information by sending pulses of light (using laser) through an optic fiber. The low signal loss in optic fibers and high data rate of transmission systems, allow signals with high data rates (exceeding several Gbps) to travel over long distances (more than 100 km) without a need of repeater or amplifier. Moreover, using wavelength division multiplexing (WDM) allows a single fiber to carry multiple signals (upto 10 different signals) of multi-Gbps transmissions. Optic Fiber communication offers extremely high bandwidth, immunity to electromagnetic interference, non-existent delays and immunity from interception by external means. In the 1980s and 1990s, the continents were linked together using undersea optic fiber bringing about a paradigm shift in the global telecommunications.

These advancements in optic fiber communication has resulted in decrease of satellite communications for several types of communications. For instance, transmission between fixed locations or point-to-point communications, where large bandwidths are required (such as transoceanic telephone systems) are made through optic fiber instead of using satellite communication. Optic Fiber communication is also used to transmit telephone signals, Internet communication, LAN (Gigabit LAN) and cable television signals.

Satellite Communication

Satellite communications use artificial satellites as relays between a transmitter and a receiver at different locations on Earth. Satellite systems allow users to bypass typical carrier offices and to broadcast information to multiple locations. Communications satellites are used for radio, TV, telephone, Internet, military and other applications. There are more than 2,000 satellites around Earth’s orbit, being used for communication by both government and private organizations.

Communication Satellites are LOS (line-of-sight) microwave systems with a repeater. These satellites rotate around the earth with the speed of earth and are known as geostationary satellites. The limitations of antenna size also limits focusing capability making the coverage for a single satellite transmitter very large. This makes satellite communication ideal for TV and radio services as the signal has to flow from a single point to many points in a single direction. The large distance of satellites from the earth (about 22,300 miles) results in delays which adversely effects two-way communication like mobile conversations. Low earth orbit satellites can be used for two-way mobile communication because less power is required to reach those satellites.

Explanation:

Answer:

11460 years

Explanation:

0.693/t1/2 = 2.303/t log (No/N)

t1/2 = half life of the carbon

t = age of the fossil

No= amount of radioactive material originally present

N= amount of radioactive material present at time=t

No= mass of carbon + nitrogen = 5g

0.693/5730 = 2.303/t log (5/1.25)

1.21 ×10^-4 = 1.3866/t

t= 1.3866/1.21 ×10^-4

t= 11460 years

Answer:

8

Explanation:

The atomic mass of an atom refers to the number of protons in the nucleus of an atom. Hence, an element with 6 valence electron mean that it has 6 electrons in its outermost shell.

The atomic Number of elements with 6 valence electrons cannot necessarily be the same, however, elements with 6 valence electrons belong to group six on the periodic table.

From the options given above, :

Atomic number of 8 :

Configuration : 2, 6

Atomic number of 10 :

Configuration : 2, 8

Atomic number of 12 :

Configuration : 2, 8, 2

Hence, only the element with atomic number of 8 has 6 valence electrons in its outer most shell, hence, the answer.

Answer:

fr

Explanation:

Answer:

after 45 days 9 g left

Explanation:

Given data:

Half life Na-24 = 15 days

Mass of sample = 72 g

Mass remain after 45 days = ?

Solution:

Number of half lives passed:

Number of half lives = time elapsed / half life

Number of half lives = 45 days / 15 days

Number of half lives = 3

At time zero total amount = 72 g

After first half life = 72 g/ 2= 36 g

At 2nd half life = 36 g/2 = 18 g

At 3rd half life = 18 g/2 = 9 g

Thus after 45 days 9 g left.

Answer: conduction

Explanation:

the heat passes out of the stove and into your hand. So is holding an ice cube – the heat is conducted out of your hand, and into the ice cube (that’s why your hand feels cold).

Answer:

Conduction

Explanation:

Conduction occurs when objects touch. The heat from the warmer object is transferred to the cooler object, eventually evening out the temperatures.

Answer:  

Here is a picture of all the elements

Answer:

The periodic table is a tabular array of the chemical elements organized by atomic number, from the element with the lowest atomic number, hydrogen, to the element with the highest atomic number, oganesson. The atomic number of an element is the number of protons in the nucleus of an atom of that element.

Explanation:

PLEASE MARK ME AS BRAINLIEST

Answer:

0.0584 M

Explanation:

From the question given above, the following data were obtained:

Mass of CaCl₂ = 0.808 g

Volume of water = 250 mL

Concentration of chloride =?

Next, we shall determine the number of mole in 0.808 g of CaCl₂. This can be obtained as follow:

Mass of CaCl₂ = 0.808 g

Molar mass of CaCl₂ = 40 + (35.5 × 2)

= 40 + 71

= 111 g/mol

Mole of CaCl₂ =?

Mole = mass / Molar mass

Mole of CaCl₂ = 0.808 / 111

Mole of CaCl₂ = 0.0073 mole

Next, we shall convert 250 mL to L. This can be obtained as follow:

1000 mL = 1 L

Therefore,

250 mL = 250 mL × 1 L / 1000 mL

250 mL = 0.25 L

Next, we shall determine the molarity of CaCl₂. This can be obtained as follow:

Mole of CaCl₂ = 0.0073 mole

Volume of water = 0.25 L

Molarity of CaCl₂ =?

Molarity = mole /Volume

Molarity of CaCl₂ = 0.0073 / 0.25

Molarity of CaCl₂ = 0.0292 M

Finally, we shall determine the concentration of the chloride as illustrated below:

CaCl₂ <=> Ca²⁺ + 2Cl¯

From the equation above,

1 mole of CaCl₂ produced 2 mole of Cl¯.

Therefore, 0.0292 M CaCl₂ will produce = 0.0292 × 2 = 0.0584 M Cl¯.

Thus, the concentration of the chloride ion (Cl¯) in the solution is 0.0584 M

Explanation:

Heat is transferred by conduction when adjacent atoms vibrate against one another or electrons move from one atom to another . Conduction is the most significant meanings of heat transfer within a solid or between solid objects informal contact.

Answer: When the spring is recoiling

Explanation:

Answer:

When the spring is recoiling

Explanation:

Answer:

12.01% by mass

Explanation:

Percent by mass is 100 times the mass of solute (ammonia) over the mass of the solution. In molarity, we have the moles of ammonia per liter of solution. There are 6.70moles of NH3 in 1L. Thus, we need to convert the moles of ammonia to grams and the liters of solution to grams:

Mass ammonia - Molar mass: 17.031g/mol-

6.70moles * (17.031g / mol) = 114.1g NH₃

Mass solution:

1L * (1000mL / 1L) = 1000mL * (0.950g/mL) = 950g

Percent by mass:

114.1g NH₃ / 950g * 100 =

Answer: The hydroxide concentration of this sample is [tex]3.85\times 10^{-7}[/tex]

Explanation:

When an expression is formed by taking the product of concentration of ions raised to the power of their stoichiometric coefficients in the solution of a salt is known as ionic product.

The ionic product for water is written as:

[tex]K_w=[H^+]\times [OH^-][/tex]

[tex]7.7\times 10^{-14}=[H^+]\times [OH^-][/tex]

As [tex][H^+]=[OH^-][/tex]

[tex]2[OH^-]=7.7\times 10^{-14}[/tex]

[tex][OH^-]=3.85\times 10^{-7}[/tex]

Thus hydroxide concentration of this sample is [tex]3.85\times 10^{-7}[/tex]

Answer:

2KCl + F₂   →     2KF + Cl₂

Explanation:

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

For example:

2KCl + F₂   →     2KF + Cl₂

In this equation mass of reactant and product is equal. There are 2 potassium 2 chlorine and fluorine atoms on both side of equation it means mass remain conserved.

All other options are incorrect because mass is not conserved.

Answer:

Hallo

Explanation:

I took that question

the answer is mitosis