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3 years ago

When heat energy is removed, two changes are observed:

Chemistry

2 answers:

Softa [21]3 years ago

3 0

Answer: A is condensation and B is freezing.

The process in which the gas changes to the liquid phase due to the removal of heat is known as condensation. Rains are formed in this way. The water vapour rises. As it raises above it loses heat and then cools down and condenses and comes down as rainfall.

The process in which the liquid changes to a solid on removal of heat is known as freezing. Formation of ice is an example. When the heat is removed at -4 degree Celsius the water freezes to ice.

nikitadnepr [17]3 years ago

3 0

Answer:

A is condensation and B is freezing.

Explanation:

Condensation is the process in which a gas changes into a liquid. Evaporation is the process in which a liquid changes into a gas. Freezing is when liquid changes to solid/solid liquid. Melting is when a solid/solid liquid changes to liquid.

In change A, a gas changes to a liquid; this is called condensation

In change B, a liquid changes into a solid; this is called freezing.

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A 1.540 gram sample of an alloy containing only tin and zinc was reacted with excess fluorine gas to produce 2.489 grams in tota

sineoko [7]

Answer:

Tin: 54.3%

Zinc: 45.7%

Explanation:

The molar masses of the elements are:

Tin: Sn = 117.710 g/mol

Zinc: Zn = 65.409 g/mol

Fluorine: F = 18.998 g/mol

The fluorine gas in excess, so the reaction consumes all the alloy, and all the tin is converted to SnF₄ and all the zinc is converted to ZnF₂. The molar masses of the fluorides are:

SnF₄ = 117.710 + 4*18.998 = 193.702 g/mol

ZnF₂ = 65.409 + 2*18.998 = 103.405 g/mol

If we call x the number of moles of SnF₄, and y the number of moles of ZnF₂, the total mass can be calculated knowing that the mass is the number of moles multiplied by the molar mass:

193.702x + 103.405y = 2.489

The number of moles of Sn is the same as SnF₄ (1:1), and also the number of moles of Zn is the same as ZnF₂ (1:1), so the mass of the alloy:

117.710x + 65.409y = 1.540

if we multiply it by -1.581 and sum with the other equation:

117.710x*(-1.581) + 65.409y*(-1.581) + 193.702x + 103.405y = 1.540*(-1.581) + 2.489

7.60249x = 0.05426

x = 0.0071 mol of Sn

117.710*0.0071 + 65.409y = 1.540

65.409y = 0.704259

y = 0.0108 mol of Zn

The masses are the molar mass multiplied by the number of moles:

Sn: 117.710*0.0071 = 0.836 g

Zn: 65.409*0.0108 = 0.704 g

The percent composition is the mass of the substance divided by the total mass multiplied by 100%:

Sn: (0.836/1.540)*100% = 54.3%

Zn: (0.704/1.540)*100% = 45.7%

6 0

3 years ago

Iodine is blue-black, crystalline, and solid. It sublimes to a violet-colored gas and reacts with aluminum and many other metals

Pepsi [2]

Answer:

blue-black PHYSICAL PROPERTY
crystalline PHYSICAL PROPERTY
solid PHYSICAL PROPERTY
sublimes to a violet-colored gas PHYSICAL PROPERTY
reacts with aluminum and many other metals CHEMICAL PROPERTY

Explanation:

Chemical properties are visible through chemical reactions, in which the chemical identity changes to form new substances. On the other hand, physical properties are evident without a change in the identity of a substance.

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<em>Which of these five properties are physical and which are chemical?</em>

blue-black PHYSICAL PROPERTY
crystalline PHYSICAL PROPERTY
solid PHYSICAL PROPERTY
sublimes to a violet-colored gas PHYSICAL PROPERTY
reacts with aluminum and many other metals CHEMICAL PROPERTY

4 0

3 years ago

Mole ratio of co2 carbonate to water

tino4ka555 [31]

Pls make ur question alittle clearer by may be saying the chemical compound or writing the required reaction

4 0

3 years ago

Which of the following is the largest volume? 4.0 x 101 m3 3.8 x 107 cm3 3.8 x 105 dm3 3.8 x 108 mm3

fiasKO [112]

Answer : Option A) 4.0 X 101 $m^{3}$

Explanation : As per the measurement chart the greatest metric system is measured in meters.

So the rest values are given in the form of metric values which are obviously less than that of meters. values of centimeters, decimeter and millimeters are less than that of meters.

8 0

3 years ago

Which type of reaction?

polet [3.4K]

condensation polymerization, since a byproduct of the reaction is a single molecule of water (hence condensation of water)

addition polymerization is if you add the two polymers together like blocks and should have no byproducts

esterification is when you combine an organic acid with an alcohol. Since neither of the two polymers look like acids, you can rule this out.

never heard of saponification, Im an mechanical engineer not an organic chemist

3 0

3 years ago