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3 years ago

A piece of copper at 10 °C is dropped into a glass of water at 35 °C. Which statement is correct?

Chemistry

2 answers:

kakasveta [241]3 years ago

8 0

I say B. Why? because the heat will keep on moving in molecules until it reaches same temperature

Sergeu [11.5K]3 years ago

5 0

Answer:

The correct answer is option B, that is, heat will flow from the water in the glass to the copper until both reach the same temperature.

Explanation:

Let us see a perfectly thermal insulation system with a glass of water at higher temperatures and a piece of copper at a lower temperature, and when both encounters each other than water will lose some of the heat and that heat will be gained by the copper. The procedure will take place until and unless both attain a similar temperature. After attaining a similar temperature, there will be no change in temperature or heat between the two. The change in heat is a function of temperature difference.

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Describes two uses of surfactants at least one must be something that was not described in the passage

Morgarella [4.7K]

Answer:

We don't have the passage. A random sampling of surfactant uses includes:

removal of oily materials from objects (clothes and dishes)
forms remarkable structures called bubbles
Assists in forming emulsions (e.g., mayonaise and paints)

Explanation:

The structure of a surfactant makes one end of a molecule hydrophilic and the other end hydrophobic. In water, they self-assemble into micelles, an arrangement in which the hydrophobic ends align towards the center, and the hydrophilic ends are pointed outwards to the water. This self-assembly is apparant when bubbles are made. The molecules quickly align themselves such that the hyrophilic ends are oriented inwards towards a thin layer of water and the hydrophobic ends are pointed outward to the air. This arrangement allows a mono-molecular sphere of water molecules to remain stable enough to float, reflect light, and please. These same properties allow the inverse to occur. Soap molecules surround a hydrophobic mass (e.g., the hamburger grease on your shirt) and solubilize it into small micelles which are then carried away in the surrounding water.

4 0

2 years ago

Noble Gases (18): (Name all noble gases)

Paul [167]

Answer :

The Noble gasses are Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn).

When air is cold, Oxygen liquefies first at $-182^oC$ . $N_2$ liquefies at $-195^oC$ . About 1% of the air is still gas composed of the noble gas Argon, Ar.
One noble gas was discovered on the sun. It’s spectrum was identify first. This is Helium, He.
One of noble gas is radioactive and seeps up your basement floors and walls. It is Radon, Rn.
This noble gas is used in electronic flashes and other bright lights. It is Xenon, Xe.
This noble gas is best known for its orange color in gas discharge tubes. It is used for signs that bear its name. It is Neon, Ne.

3 0

3 years ago

Assuming equal concentrations, rank these solutions by ph.? assuming equal concentrations, rank these solutions by ph. koh (aq h

polet [3.4K]

I remember coming across this question and the options were:
KOH, HCN, NH₃, HI, Sr(OH)₂

Now, a substance with a low pH is one that dissociates completely in water to release hydrogen ions, while basic substances dissociate completely to release hydroxide ions. Therefore, in the order of increasing pH:
HI, HCN, NH₃, Sr(OH)₂, KOH

7 0

3 years ago

A chemical reaction that releases heat to the surroundings is said to be __________ and has a __________ H at constant pressure

Savatey [412]

Answer:

The correct option is c) exothermic, negative.

Explanation:

Reactions that releases heat to the surroundings are called exothermic, and are characterized by negative entalpy (ΔH) values.

6 0

3 years ago

1. How many moles of nitrogen monoxide can be made using 5.0 moles of oxygen in

FrozenT [24]

Answer:

1) 10.0 moles of NO

2) 25 moles of NaCl

3) 1200 moles of CO2

4) 1.03 moles of MgO

5) 0.72 moles H2

6) 1041.15 grams BaCl2

7) 9.55 grams MgO

8) 45.5 grams Au

9 )14.93 grams AlCl3

Explanation:

1. How many moles of nitrogen monoxide can be made using 5.0 moles of oxygen in the following composition reaction?

N2 + O2 → 2NO

For 1 mol N2 we need 1 mol O2 to produce 2 moles of NO

For 5.0 moles of N2 we need 5.0 moles of O2 to produce 10.0 moles of NO

2. The neutralization of an acid with a base is a double replacement reaction in which a salt and water are formed. If you start with 25 moles of HCl and neutralize it with NaOH how many moles of NaCl will be formed?

HCl + NaOH → NaCl + H2O

For 1 mol HCl we need 1 mol NaOH to produce 1 mol of NaCl and 1 mol H2O

For 25 moles of HCl we need 25 moles of NaOH to produce 25 moles of NaCl and 25 moles of H2O

3. A car burns gasoline (octane – C8H18) with oxygen. If you drive to Salt Lake and burn 150 moles of octane how many moles of carbon dioxide are you producing?

2C8H18 + 25O2 → 16CO2 + 18H2O

For 2 moles of octane we need 25 moles of O2 to produce 16 moles of CO2 and 18 moles of H2O

For 150 moles of octane we need 25*75 = 1875 moles of O2

To produce 16*75 = 1200 moles of CO2 and 18*75= 1350 moles

4. If 25 gram of magnesium combines with oxygen in a composition reaction, how many moles of magnesium oxide will be formed?

2Mg + O2 → 2MgO

Moles of Mg = 25.0 g/24.3 g/mol = 1.03 moles

For 2 moles Mg we need 1 mol O2 to produce 2 moles MgO

For 1.03 moles Mg we'll have 1.03 moles of MgO

5. . Lithium reacts with water in a single replacement reaction. How many moles of hydrogen gas a produced by 10 grams of lithium?

2Li + 2H2O → 2LiOH + H2

Moles Li = 10.0 grams/ 6.94 g/mol = 1.44 moles

For 2 moles Li we need 2 mole H2O to produce 2 moles LiOH and 1 mol H2

For 1.44 moles Li we need 1.44 moles H2O to produce 1.44 moles H2O and 0.72 moles H2

6. Barium chloride reacts with sodium sulfate in a double replacement reaction. How many grams of barium chloride are required to react with 5 moles of sodium sulfate?

BaCl2 + Na2SO4 → BaSO4 + 2NaCl

For 1 mol of BaCl2 we need 1 mol of Na2SO4 to produce 1 mol of BaSO4 and 2 moles NaCl

For 5 moles Na2SO4 we need 5 moles BaCl2

mass BaCl2 = 5 moles * 208.23 g/mol = 1041.15 grams BaCl2

7. Magnesium carbonate when heated decomposes to form magnesium oxide and carbon dioxide. How many grams of magnesium oxide will be formed if 20 grams of magnesium carbonate are heated?

MgCO3 → MgO + CO2

Moles MgCO3 = 20.0 grams / 84.31 g/mol

Moles MgCO3 = 0.237 moles

For 1 mol MgCO3 we'll have 1 mol MgO and 1 mol CO2

For 0.237 moles MgCO3 we'll have 0.237 moles MgO and 0.237 moles CO2

Mass MgO = 0.237 moles * 40.30 g/mol = 9.55 grams MgO

8. If 70 grams of gold III chloride decomposes into its elements, how many grams of gold will be produced?

2AuCl3 → 2Au + 3Cl2

Moles AuCl3 = 70 grams / 303.33 g/mol = 0.231 moles

For 2 moles AuCl3 we'll have 2 moles gold and 3 moles Cl2

For 0.231 moles AuCl3 we'll have 0.231 moles gold

Mass of gold = 0.231 moles * 196.97 g/mol = 45.5 grams Au

9. Chlorine is more reactive element than bromine, thus chlorine will replace bromine in compound through a single replacement reaction. If 30 grams of aluminum bromide react with chlorine in this fashion how many grams of aluminum chloride will be formed?

2AlBr3 + 3Cl2 → 2AlCl3 + 3Br2

Moles AlBr3 = 30 g /266.69 g/mol = 0.112 moles

For 2 moles AlBr2 we need 3 moles Cl2 to produce 2 moles AlCl3 and 3 moles Br2

For 0.112 moles AlBr3 we need 3/2 * 0.112 = 0.168 moles of Cl2

To produce 0.112 moles of AlCl3 and 0.168 moles of Br2

Mass AlCl3 = 0.112 moles * 133.34 g/mol = 14.93 grams AlCl3

8 0

3 years ago