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Cloud [144]
3 years ago
10

PLEASE HELP BRAINLIEST 4 BEST ANSWER

Chemistry
2 answers:
german3 years ago
7 0

Answer:

Helium. Symbol for Helium is: He . The atomic number (Z) is: 2. The mass number (A): 4. Common human uses of the element: Because it is very unreactive, helium is used to provide an inert protective atmosphere for making fiber optics and semiconductors, and for arc welding. Helium is also used to detect leaks, such as in car air-conditioning systems, and because it diffuses quickly it is used to inflate car airbags after impact. present in a common molecule: Helium does not bond with the other atoms. if its dangerous: helium can cut off oxygen supply or can cause an embolism if a person inhales too deeply.

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Carbon. Symbol: C. The atomic number (Z): 6. The mass number (A): 12. Common human uses of the carbon: is used in metal smelting. It is particularly important in the iron and steel industries. Graphite is used in pencils, to make brushes in electric motors and in furnace linings. Activated charcoal is used for purification and filtration. The carbon atom has unique properties that allow it to form covalent bonds to as many as four different atoms, making this versatile element ideal to serve as the basic structural component, or “backbone,” of the macromolecules. Individual carbon atoms have an incomplete outermost electron shell. If its dangerous: Elemental carbon is of very low toxicity. Health hazard data presented here is based on exposures to carbon black, not elemental carbon. Chronic inhalation exposure to carbon black may result in temporary or permanent damage to lungs and heart.

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Sodium. The Symbol: Na. Atomic number: 11. Mass number: 23. Common human uses : Sodium is important for many different functions of the human body. For example, it helps cells to transmit nerve signals and regulate water levels in tissues and blood. Sodium is the sixth most common element on Earth, and makes up 2.6% of the Earth's crust. The most common compound is sodium chloride. The most common compound of sodium is sodium chloride (common salt). If its dangerous: Sodium is essential to human health, but too much sodium is poisonous. Sodium poisoning can cause seizures, coma, and death.

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Nitrogen. Symbol: N. Atomic number :7. Mass number: 14. Common human uses :Human activities, such as making fertilizers and burning fossil fuels, have significantly altered the amount of fixed nitrogen in the Earth's ecosystems. If its present in a common molecule: Common compounds with nitrogen atoms include ammonia (NH3), nitrous oxide (N2O), nitrites, and nitrates. Nitrogen is also found in organic compounds such as amines, amides, and nitro groups. If its dangerous: High concentrations of nitrogen gas can be particularly harmful to human health. Nitrogen can displace oxygen from ambient air within an enclosed space leading to a dangerous build-up of the inert gas.

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Potassium. Symbol: K. Atomic number: 19. Mass number:39.  Common human uses: Potassium is a mineral that plays many important roles in the body. Food sources of potassium include fruits (especially dried fruits), cereals, beans, milk, and vegetables. Potassium is most commonly used for treating and preventing low potassium levels, treating high blood pressure, and preventing stroke.  If its present in a common molecule: Potassium forms many important compounds. Potassium chloride (KCl) is the most common potassium compound. It is used in fertilizers, as a salt substitute and to produce other chemicals. Potassium hydroxide (KOH) is used to make soaps, detergents and drain cleaners. If its dangerous: Having too much potassium in your blood can be dangerous. Potassium affects the way your heart's muscles work. When you have too much potassium, your heart may beat irregularly, which in the worst cases, can cause heart attack.

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Minchanka [31]3 years ago
3 0

Answer:

The correct answer's B, give brainly if this helped :)

Explanation:

You might be interested in
Any help would be appreciated. Confused.
masya89 [10]

Answer:

q(problem 1) = 25,050 joules;  q(problem 2) = 4.52 x 10⁶ joules

Explanation:

To understand these type problems one needs to go through a simple set of calculations relating to the 'HEATING CURVE OF WATER'. That is, consider the following problem ...

=> Calculate the total amount of heat needed to convert 10g ice at -10°C to steam at 110°C. Given are the following constants:

Heat of fusion (ΔHₓ) = 80 cal/gram

Heat of vaporization (ΔHv) = 540 cal/gram

specific heat of ice [c(i)] = 0.50 cal/gram·°C

specific heat of water [c(w)] = 1.00 cal/gram·°C

specific heat of steam [c(s)] = 0.48 cal/gram·°C

Now, the problem calculates the heat flow in each of five (5) phase transition regions based on the heating curve of water (see attached graph below this post) ...   Note two types of regions (1) regions of increasing slopes use q = mcΔT and (2) regions of zero slopes use q = m·ΔH.

q(warming ice) =  m·c(i)·ΔT = (10g)(0.50 cal/g°C)(10°C) = 50 cal

q(melting) = m·ΔHₓ = (10g)(80cal/g) 800 cal

q(warming water) = m·c(w)·ΔT = (10g)(1.00 cal/g°C)(100°C) = 1000 cal

q(evaporation of water) =  m·ΔHv = (10g)(540cal/g) = 5400 cal

q(heating steam) = m·c(s)·ΔT = (10g)(0.48 cal/g°C)(10°C) = 48 cal

Q(total) = ∑q = (50 + 800 + 1000 + 5400 + 48) = 7298 cals. => to convert to joules, multiply by 4.184 j/cal => q = 7298 cals x 4.184 j/cal = 30,534 joules = 30.5 Kj.

Now, for the problems in your post ... they represent fragments of the above problem. All you need to do is decide if the problem contains a temperature change (use q = m·c·ΔT) or does NOT contain a temperature change (use q = m·ΔH).    

Problem 1: Given Heat of Fusion of Water = 334 j/g, determine heat needed to melt 75g ice.

Since this is a phase transition (melting), NO temperature change occurs; use q = m·ΔHₓ = (75g)(334 j/g) = 25,050 joules.

Problem 2: Given Heat of Vaporization = 2260 j/g; determine the amount of heat needed to boil to vapor 2 Liters water ( = 2000 grams water ).

Since this is a phase transition (boiling = evaporation), NO temperature change occurs; use q = m·ΔHf = (2000g)(2260 j/g) = 4,520,000 joules = 4.52 x 10⁶ joules.

Problems containing a temperature change:

NOTE: A specific temperature change will be evident in the context of problems containing temperature change => use q = m·c·ΔT. Such is associated with the increasing slope regions of the heating curve.  Good luck on your efforts. Doc :-)

5 0
3 years ago
Answer the question PLS 100 points!!!
cluponka [151]
  • 1atm=760mm Hg

Now

  • 1.36atm
  • 1.36(760)
  • 1033.6mm Hg

Done!

5 0
2 years ago
Chemists can use moles to calculate: A. How much of the products are needed and how much reactant will be made. B. How much prod
damaskus [11]

Answer:

c.- How much of the reactants are needed and how much product will made.

Explanation:

The moles is the matter unit used in chemistry to simplify  some calculations, instead of using grams. Also the moles are very useful because the chemical reaction can be balanced.

When a Chemical reaction is balanced, then it can be easily to calculate how many moles are necessary to add in a process to obtain a quantity of grams of a product.

5 0
3 years ago
When the temperature of a reacting mixture increases, the rate of reaction increases. Which statement explains why the rate of r
wlad13 [49]

Answer:

This is one of the factors that affects chemical reactions

Temperature:This is because when the temperature is raised energy in form of heat is supplied to the reacting particles and so the rate of reaction is increased.

3 0
3 years ago
There are seven major levels of classification. Kingdom and Phylum are just two of the levels. Which of the following are also m
kumpel [21]
A) The class and C) Family would be the only accurate option. Here are the levels from largest to smallest: <span>kingdom, phylum, class, order, family, genus and species.</span>
7 0
3 years ago
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