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2 years ago

) Which direction does thermal energy flow in the following diagram? *

Chemistry

1 answer:

Karo-lina-s [1.5K]2 years ago

3 0

Answer:

the heat flows from the hand to the ice cream

Explanation:

we produce body heat therefore it moves to the ice cream also there is no possible way the heat could move from the ice cream because the ice cream is cold

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His transmitter is mostly located in diffuse neuronal systems in the CNS, with cell bodies particularly in the raphe nuclei. It

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Answer: The correct answer is a) Acetylcholine.

Explanation:

The acetylcholine is a very important neurotransmitter involved in the mediation of synaptic activity between neurons. Among its most important functions we find: expression of mood states, vasodilation, gastrointestinal motility, bronchoconstriction, circular iris muscle contraction and sweat gland secretion.

Therefore the correct answer is a) Acetylcholine.

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4 years ago

If you have 100 particles of hydrogen and 100 particles of oxygen, how many units of water can you form? Will you use all the pa

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Explanation:

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3 years ago

Air resistance depends upon _____.

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Answer:

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3 years ago

What are some chemical/physical properties that make calcium hazardous or useful? 50 points for this

Talja [164]

"Calcium's chemical properties are attributed to its location in group 2 of the periodic table. As an alkaline earth metal, it is a good reducing agent for preparing other metals, such as uranium and thorium. It reacts violently when placed in water, forming calcium hydroxide, more commonly known as lime. This is the reason why water that is high in calcium causes lime buildup on the interior of pipes. Calcium also reacts rapidly when exposed to air. It develops an oxide coating, which prevents the mass of calcium from corroding. If exposed to air at a high temperature, calcium burns to produce nitride. The most common calcium isotope is Calcium-40. It has an ionic radius of 0.099 nm, a standard potential of -2.87 volts and an ionization energy of 589.6 kJ per mole. Calcium compounds are important in a number of industries. Calcium oxide, for example, is used in high intensity lights. Calcium hydroxide is useful for breaking down wood and rocks".
-Reference.com
"The calcium oxide, Ca(OH)2, has many applications in which the hydroxyl ion is necessary. In the process of calcium hydroxide quenching, the volume of blown out lime [Ca(OH)2] expends to double the initial quantity of quick lime (CaO), fact that makes it useful to break down rocks or wood".

"The quick lime is an excellent absorbent for the carbon dioxide, because it produces carbonate, which is very insoluble".

"The calcium silicate, CaSi, prepared in an electric oven from lime, silica and reducing carbonated agents, is useful as a steel-deoxidizing agent. Calcium carbide, CaC2, is produces when heating up a mixture of lime and carbon at 3000ºC in an electric oven and it is an acetylate which produces acetylene by hydrolysis. The acetylene is the base material of a great number of important chemicals for the organic industrial chemistry".

"The pure calcium carbonate occurs in two crystalline forms: calcite, hexagonal shaped, which possesses birrefringent properties, and aragonite, rhombohedric. The natural carbonates are the most abundant calcium minerals. The Iceland spar and the calcite are essentially pure carbonate forms, whilst the marble is impure and much more compact, reason why it can be polished. It’s very demanded as construction material. Although the calcium carbonate is very little soluble in water, it is quite soluble if the water contains dissolved carbon dioxide, for in these solutions it forms bicarbonate when dissolving. This fact explains the cave formation, where the lime stone deposits have been in contact with acid waters".
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6 0

3 years ago

A propane stove burned 470 grams propane and produced 625 grams of water (this is the actual yield) C3H8 +5O2=3CO2+4H20. What wa

Liula [17]

Answer:

81.3%

Explanation:

Step 1:

The balanced equation for the reaction:

This is shown below:

C3H8 + 5O2 —> 3CO2 + 4H2O

Step 2:

Data obtained from the question. This includes:

Mass of propane (C3H8) = 470 g

Actual yield of water (H2O) = 625 g

Percentage yield of water (H2O) =?

Step 3:

Determination of the mass of propane (C3H8) burned and the mass of water (H2O) produce from the balanced equation. This is illustrated below:

C3H8 + 5O2 —> 3CO2 + 4H2O

Molar Mass of C3H8 = (3x12) + (8x1) = 36 + 8 = 44g/mol

Molar Mass of H2O = (2x1) + 16 = 2 + 16 = 18g/mol

Mass of H2O from the balanced equation = 4 x 18 = 72g

From the balanced equation above,

44g of C3H8 was burned and 72g of H2O was produced.

Step 4:

Determination of the theoretical yield of H2O. This is illustrated below:

From the balanced equation above,

44g of C3H8 produced 72g of H2O.

Therefore, 470g of C3H8 will produce = (470x72)/44 = 769.09g of H2O.

Therefore, the theoretical yield of H2O is 769.09g

Step 5:

Determination of the percentage yield of water (H2O). This is illustrated below:

Actual yield of water (H2O) = 625g

theoretical yield of H2O = 769.09g

Percentage yield of water (H2O) =?

Percentage yield = Actual yield/Theoretical yield x100

Percentage yield = 625/769.09 x100

Percentage yield = 81.3%

Therefore, the percentage yield of water (H2O) is 81.3%

4 0

4 years ago