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The proton is a postitive charge, therefore, being 1 (proton) matched to positive. Whilst neutron (2) is matched to neutral. Thus electron (3) is matched to negative.

Answer:

–4020 KJ

Explanation:

The following data were obtained from the question:

H₂(g) + F₂(g) —> 2HF(g) ΔH = –536 KJ

Next, we shall determine the mass of H₂ that reacted from the balanced equation to produce –536 KJ of heat energy. This can be obtained as follow:

Molar mass of H₂ = 2 × 1 = 2 g/mol

Mass of H₂ from the balanced equation = 1 × 2 = 2 g.

Summary:

From the balanced equation above,

2 g of H₂ reacted to produce –536 KJ of heat energy.

Finally, we shall determine the heat change produced by the reaction of 15 g of H₂. This can be obtained as follow:

From the balanced equation above,

2 g of H₂ reacted to produce –536 KJ of heat energy.

Therefore, 15 g of H₂ will react to produce = (15 × –536)/2 = –4020 KJ of heat energy.

Thus, the heat change for the reaction is –4020 KJ

Answer:D

Explanation:trust me bro

Answer:

D

Explanation: I took the test

Answer:

How do atoms give off light?

Atoms emit light when they are heated or excited at high energy levels. The color of light that is emitted by an atom depends on how much energy the electron releases as it moves down different energy levels. ... It shows the electron moving down energy levels.

Explanation:

Answer: One formula unit of NaCl consists of one cation, whose chemical symbol is [tex]Na^+[/tex] and one anion whose chemical symbol is [tex]Cl^-[/tex]

Explanation:

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.  

The cation is formed by the metal sodium which forms  [tex]Na^+[/tex] and the anion is formed by non metal chlorine which forms [tex]Cl^-[/tex].

For a formula unit of sodium chloride,  the charges have to be balanced , thus the valencies of ions are exchanged and the neutral compound result. Thus

[tex]Na^+[/tex] and  [tex]Cl^-[/tex] combine to form neutral [tex]NaCl[/tex]

Answer:

a small medical thermometer with a short but finely calibrated range, for taking a person's temperature.

Answer:

Thermometer which are used in clinical to measure the temperature of human body is called clinical thermometer.

Answer:

a sea of electrons

Iron metal has a sea of electrons.

Iron metal is an element which possesses a sea of electrons as a result of it

containing cations which are usually surrounded by electrons which move at

a very fast pace .

This property makes Iron metal to be reactive when exposed to air( oxygen)

and it then forms various compounds such as Iron(II) oxide, Iron(III) oxide and

rust.

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Answer:

they are either donated to or taken by another atom to achieve octet arrangement

Explanation:

for example Na+ and Cl- .. they both have one extra and one less electron .

so they donate and receive one electron to/from each other to achieve the octet arrangement ..

Answer and Explanation:

HCl, also known as hydrochloric acid, has a covalent bond. The hydrogen (H) atom shares an electron with the chlorine (Cl) to form the bond.

Answer:

Explanation:

21:B 22:B

Answer:

Fe (s) + Cu^2+ (aq) + SO4^2- (aq) --> Cu (s) + Fe^2+ (aq) + SO4^2- (aq)

Explanation:

Answer:

C. read the label on the container

Explanation:

What information is found in an SDS? Check all that apply.

A. the identification of the chemical

C. the chemical and physical properties of the substance

D. the first-aid measures to take if an accident occurs involving the chemical

Answer:

C

Explanation:

just did it

Water boils when the vapour pressure is least the atmospheric pressure.

The atmospheric pressure is equal at the top of the mountain.

The air around you has weight, and it presses against everything it touches. That pressure is called atmospheric pressure, or air pressure. It is the force exerted on a surface by the air above it as gravity pulls it to Earth.

As we go up in altitude the air pressure becomes less. When the pressure decreases, it takes less energy to get the water molecules to escape the surface. So the temperature is less than it would be at sea level.

Air pressure is higher or greater at the bottom of a mountain. This is because the height of the air above that level is thicker than at the top.

Pressure is given by the equation, P=rho*g*h, where rho is the air density, g is the gravity value and h is the thickness of the air layer on top of the level where we are considering the pressure.

Therefore, as we can see, at the bottom of the mountain, the thickness h of air is greater, and so is the pressure.

Hence, water boils when the vapour pressure is least the atmospheric pressure and the atmospheric pressure is equal at the top of the mountain.

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Answer:

Protons, neutrons, and electrons are the three main subatomic particles found in an atom. Protons have a positive (+) charge. An easy way to remember this is to remember that both proton and positive start with the letter "P." Neutrons have no electrical charge.

Answer:

Protons, positive charge

Neutrons, neutral

Electrons, negative charge

Explanation:

Answer: 1. Phys 2. Phys 3. Phys 4. Chem 5. Chem 6. Phys 7. Phys 8. Phys

Explanation:

According to the concept of physical and chemical property ,reaction with water and flammability are chemical properties while rest are physical properties.

These properties are defined as those properties which become evident during or after a chemical reaction after the identity of the substance is changed during chemical reaction.

These properties cannot be determined externally just by viewing the substance ,these change immensely after a substance undergoes a chemical change.These are used for identification of unknown substances and for building up chemical classifications.

The major chemical properties are flammability,toxicity,reactivity,acidity and heat of combustion.For a chemical property to be apparent , it is necessary that the structure of the substance is altered.

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The mass, in kg, of Sulfur produced : 2.072 kg

Given

V = 8.56 kL = 8560 L

P = 175 kPa = 1,73 atm

T = 250 + 273 = 523 K

Required

mass of Sulfur produced

Solution

mol of H₂S :

[tex]\tt n=\dfrac{PV}{RT}\\\\n=\dfrac{1.73\times 8560}{0.082\times 523}\\\\n=345.3[/tex]

mol of Sulfur based on mol  H₂S as a limiting reactant( excess Sulfur  dioxide)

From equation, mol ratio  H₂S : S = 16 : 3, so mol S :

[tex]\tt \dfrac{3}{16}\times 345.3=64.74[/tex]

Mass S(Ar = 32 g/mol) :

= mol x Ar s

= 64.74 x 32

= 2071.68 g = 2.072 kg

Answer:

Cells are the basic building blocks of living things. The human body is composed of trillions of cells, all with their own specialised function. Cells are the basic structures of all living organisms. Cells provide structure for the body, take in nutrients from food and carry out important functions.

Answer:

Your answer is going to be B. the burning of fossil fuels

Explanation:

This is because carbon monoxide is extremely toxic for us humans. An example of this could be pollution. Hope this helps! :)

Answer:

k. e. = 1/2 mv^2

100 = 1/2 * m * 5^2

100 = 1/2 * m * 25

m = 100 *2/25

m = 8 kg

hope it helps you

Answer:c

Explanation:

Anser:

Explanation:

hope this helps

Answer:

The nose consists of the visible external nose and the internal nasal cavity. The nasal septum divides the nasal cavity into right and left sides. Air enters two openings, the external nares (nostrils; singular, naris), and passes into the vestibule and through passages called meatuses. The bony walls of the meatuses, called concha, are formed by facial bones (the inferior nasal concha and the ethmoid bone). From the meatuses, air then funnels into two (left and right) internal nares. Hair, mucus, blood capillaries, and cilia that line the nasal cavity filter, moisten, warm, and eliminate debris from the passing air.

The pharynx (throat) consists of the following three regions, listed in order through which incoming air passes:

The nasopharynx receives the incoming air from the two internal nares. The two auditory tubes that equalize air pressure in the middle ear also enter here. The pharyngeal tonsil (adenoid) lies at the back of the nasopharynx.

The oropharyrnx receives air from the nasopharynx and food from the oral cavity. The palatine and lingual tonsils are located here.

The laryngopharynx passes food to the esophagus and air to the larynx.

The larynx receives air from the laryngopharynx. It consists of several pieces of cartilage that are joined by membranes and ligaments, shown in Figure 2:

The epiglottis, the first piece of cartilage of the larynx, is a flexible flap that covers the glottis, the upper region of the larynx, during swallowing to prevent the entrance of food.

The thyroid cartilage protects the front of the larynx. A forward projection of this cartilage appears as the Adam's apple (anatomically known as the laryngeal prominence).

The paired arytenoid cartilages in the rear are horizontally attached to the thyroid cartilage in the front by folds of mucous membranes. The upper vestibular folds (false vocal cords) contain muscle fibers that bring the folds together and allow the breath to be held during periods of muscular pressure on the thoracic cavity (straining while defecating or lifting a heavy object, for example). The lower vocal folds (true vocal cords) contain elastic ligaments that vibrate when skeletal muscles move them into the path of outgoing air. Various sounds, including speech, are produced in this manner.

The cricoid cartilage, the paired cuneiform cartilages, and the paired corniculate cartilages are the remaining cartilages supporting the larynx.

The trachea (windpipe) is a flexible tube, 10 to 12 cm (4 inches) long and 2.5 cm (1 inch) in diameter (Figure 2).

The mucosa is the inner layer of the trachea. It contains mucus‐producing goblet cells and pseudostratified ciliated epithelium. The movement of the cilia sweeps debris away from the lungs toward the pharynx.

The submucosa is a layer of areolar connective tissue that surrounds the mucosa.

Hyaline cartilage forms 16 to 20 C‐shaped rings that wrap around the submucosa. The rigid rings prevent the trachea from collapsing during inspiration.

The adventitia is the outermost layer of the trachea. It consists of areolar connective tissue.

The primary bronchi are two tubes that branch from the trachea to the left and right lungs.

Inside the lungs, each primary bronchus divides repeatedly into branches of smaller diameters, forming secondary (lobar) bronchi, tertiary (segmental) bronchi, and numerous orders of bronchioles (1 mm or less in diameter), including terminal bronchioles (0.5 mm in diameter) and microscopic respiratory bronchioles. The wall of the primary bronchi is constructed like the trachea, but as the branches of the tree get smaller, the cartilaginous rings and the mucosa are replaced by smooth muscle.

Alveolar ducts are the final branches of the bronchial tree. Each alveolar duct has enlarged, bubblelike swellings along its length. Each swelling is called an alveolus. Some adjacent alveoli are connected by alveolar pores.

The respiratory membrane consists of the alveolar and capillary walls. Gas exchange occurs across this membrane. Characteristics of this membrane follow:

Type I cells are thin, squamous epithelial cells that constitute the primary cell type of the alveolar wall. Oxygen diffusion occurs across these cells.

Type II cells are cuboidal epithelial cells that are interspersed among the type I cells. Type II cells secrete pulmonary surfactant (a phospholipid bound to a protein) that reduces the surface tension of the moisture that covers the alveolar walls. A reduction in surface tension permits oxygen to diffuse more easily into the moisture. A lower surface tension also prevents the moisture on opposite walls of an alveolus or alveolar duct from cohering and causing the minute airway to collapse.

Alveolar macrophage cells (dust cells) wander among the other cells of the alveolar wall, removing debris and microorganisms.

Answer:

Explanation: I can't give you the answer you with the sentence but i will help you the best i can

One qualitative measure of the strength of an acid or a base solution is the pH scale A logarithmic scale that relates the concentration of the hydrogen ion in solution.

Answer:

Ok:

Explanation:

4.

[tex]I_2_{(s)} + 3Cl_2_{(g)} => 2ICl_3{(s)}[/tex]

5.

[tex]NaHCO_3_{(s)} + HCl_{(aq)} => NaCl_{(aq)} + H_2O_{(l)} + CO_2_{(g)[/tex]

Answer: D. An increase in entropy

Explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from  an disordered arrangement to an ordered arrangement, the entropy is said to increase and vice versa.

For a reaction to be spontaneous, the enthalpy of the solution must decrease and the entropy must increase.

To overcome a positive enthalpy of solution and allow a solid  solute to dissolve in water, an increase in entropy would make the reaction spontaneous as the system would move to a more disordered state.