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3 years ago

Name two things that reduce friction

Chemistry

2 answers:

coldgirl [10]3 years ago

7 0

Oil and a smooth surface

photoshop1234 [79]3 years ago

5 0

Two ways are: Make the surfaces smoother and Lubrication<span> </span>

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Natural gas burns in air to form carbon dioxide and water, releasing heat. CH4(g)+2O2(g)→CO2(g)+2H2O(g) ΔHrxn = -802.3 kJ.

Olenka [21]

Answer:

1) Minimum mass of methane required to heat 45.0 g of water by 21.0°C is 0.0788 g.

2) Minimum mass of methane required to heat 50.0 g of water by 26.0°C is 0.108 g.

Explanation:

$CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(g) ,\Delta H_{rxn} =-802.3 kJ$

1) Minimum mass of methane required to raise the temperature of water by 21.0°C.

Mass of water = m = 45.0 g

Specific heat capacity of water = c = 4.18 J/g°C

Change in temperature of water = ΔT = 21.0°C.

Heat required to raise the temperature of water by 21.0°C = Q

$Q=mc\Delta T= 45.0 g\times 4.18 J/g^oC\times 21.0^oC$

Q = 3,950.1 J = 3.9501 kJ

According to reaction 1 mole of methane on combustion gives 802.3 kJ of heat.

Then 3.950.1 kJ of heat will be given by:

$=\frac{3.950.1 kJ}{802.3 kJ}=0.004923 mol$

Mass of 0.004923 moles of methane :

0.004923 mol × 16 g/mol=0.0788 g

Minimum mass of methane required to heat 45.0 g of water by 21.0°C is 0.0788 g.

2) Minimum mass of methane required to raise the temperature of water by 26.0°C.

Mass of water = m = 50.0 g

Specific heat capacity of water = c = 4.18 J/g°C

Change in temperature of water = ΔT = 26.0°C.

Heat required to raise the temperature of water by 21.0°C = Q

$Q=mc\Delta T= 50.0 g\times 4.18 J/g^oC\times 26.0^oC$

Q = 5,434 J= 5.434 kJ

According to reaction 1 mole of methane on combustion gives 802.3 kJ of heat.

Then 5.434 kJ of heat will be given by:

$=\frac{5.434 kJ}{802.3 kJ}=0.006773 mol$

Mass of 0.006773 moles of methane :

0.006773 mol × 16 g/mol= 0.108 g

Minimum mass of methane required to heat 50.0 g of water by 26.0°C is 0.108 g.

6 0

4 years ago

Commercial agriculture can often lead to water-quality problems. In one to two sentences, explain how two of those problems occu

anygoal [31]

Commercial agriculture can often lead to water-quality problems in the following ways:

The washing of fertilizers and pesticides into water bodies from farms.

<h3>What is water quality?</h3>

Water quality refers to the state of a water body that encompasses it's physical, chemical and biological characteristics.

The water quality of a water body is crucial to its suitability for domestic or drinking purpose.

Commercial agriculture greatly affects water quality in the following ways:

The washing of fertilizers and pesticides into water bodies from farms.

Learn more about water quality at: brainly.com/question/20848502

#SPJ1

4 0

2 years ago

What is the order of decreasing ionization energy?

Hatshy [7]

Your answer would be 3!!

6 0

3 years ago

The compounds n-butane, ch3(ch2)2ch3, and trimethylamine, n(ch3)3, have very similar molecular weights. However, their melting p

Ostrovityanka [42]

<h3>Answer:</h3>

The lowest boiling point is of n-Butane because it only experiences London Dispersion Forces between molecules.

<h3>Explanation:</h3>

Lets take start with the melting point of both compounds.

n-Butane = - 140 °C

Trimethylamine = - 117 °C

Intermolecular Forces in n-Butane:

As we know n-Butane is made up of Carbon and Hydrogen atoms only bonded via single covalent bonds. The electronegativity difference between C and C atoms is zero while, that between C and H atoms is 0.35 which is less than 0.4. Hence, the bonds in n-Butane are purely non polar in nature. Therefore, only London Dispersion Forces are found in n-Butane which are considered as the weakest intermolecular interactions.

Intermolecular Forces in Trimethylamine:

Trimethylamine (a tertiary amine) is made up of Nitrogen, Carbon and Hydrogen atoms bonded via single covalent bonds. The electronegativity difference between N and C atoms is 0.49 which is greater than 0.4. Hence, the C-N bond is polar in nature. Therefore, Dipole-Dipole interactions will be formed along with London Dispersion Forces which are stronger than Dispersion Forces. Therefore, due to Dipole-Dipole interactions Trimethylamine will have greater melting point than n-Butane.

5 0

4 years ago

What's the difference between a mole of propane and a gram of propane? <br>

kobusy [5.1K]

B. A gram would have a lot more molecules of propane than a mole

5 0

3 years ago