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2 years ago

What three obstacles did dmitri mendeleev face in his life

2 answers:

8 0

~He was working without prior knowledge toward creating a periodic table of elements that had been done in Europe in the 1860s

~ scandal when he got married to his second wife before he divorced his first wife

~he was working with data that was not very precise (technology didn't exist at the time to make accurate measurements (e.g., weights) for the things he was working on.) Many elements had also not been discovered yet, so he had to guess at a lot of things when making his conclusions.

OLga [1]2 years ago

6 0

Answer:

Answered

Explanation:

1. He married his second wife before giving divorce to his first wife. This made him an outsider in the scientific community making it difficult for him to raise funds for the research.

2. Back then there were no precise measuring instruments, so it was difficult for him to measure correct data. Many of the elements were yet to be discovered, so he guessed and by fortune most of his guesses were right.

3.The elements that were not discovered at that time, he left blank spaces for them.

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An increase in temperature will effect vapor pressure by:

-BARSIC- [3]

Answer: Increases.

Explanation: As the temperature of a liquid or solid increases its vapor pressure also increases. Conversely, vapor pressure decreases as the temperature decreases.

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2 years ago

The easiest way to determine whether a process is exothermic or endothermic is to note the change in temperature in a calorimete

Kryger [21]

Answer:

In the calorimeter, water is the exothermic. The salt LiCI, which will dissolve, is the endothermic. The final temperature of the water after the dissolution of LiCI was lower than the initial temperature, meaning the process is exothermic. In the microscopic view of the disspolution of LiCI, water molecules were seen to move slowly as they gained energy.

Explanation:

Exothermic is a process in which heat is released during the process. Endothermic reactions absorbs heat from surrounding during a chemical process. The dissolution of salt into water is an exothermic reaction. During this process heat is release and water molecules are broken down which are surrounded by salt ions.

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2 years ago

7. You are about to perform some intricate electrical studies on single skeletal muscle fibers from a gastronemius muscle. But f

Vilka [71]

Answer:

58.61 grams

Explanation:

Taking The molecular weight of NaCl = 58.44 grams/mole

Determine how many grams of NaCl to prepare the bath solution

first we will calculate the moles of NaCl that is contained in 6L of 170 mM of NaCI solution

= ( 6 * 170 ) / 1000

= 1020 / 1000 = 1.020 moles

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= moles of NaCl * molar mass of NaCl

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2 years ago

. Calculate the mass of O2 produced if 3.450 g potassium chlorate is completely decomposed by heating in presence of a catalyst

Vesnalui [34]

2 KClO3(s) → 3 O2(g) + 2 KCl(s)

Note: MnO2 (Manganese Dioxide) is not part of the reaction. A catalyst lowers the activation energy and increases both forward and reverse reactions at equal rates.

molar mass of KClO3 = 122.5
Moles of KClO3 = 3.45 / 122.55 = 0.028

Moles of O2 produce = $\frac{3}{2} \times 0.028$

= 0.042 moles

molar mass of O2 = 32

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2 years ago

At 800 K, the equilibrium constant, Kp, for the following reaction is 3.2 × 10–7. 2 H2S(g) ⇌ 2 H2(g) + S2(g) A reaction vessel a

djverab [1.8K]

Answer:

0.008945 atm

Explanation:

In the reaction:

2H2S(g) ⇌ 2 H2(g) + S2(g)

Kp is defined as:

$Kp = P_{H_{2}}^2P_{S_{2}} / P_{H_{2}S}^2$

Where P is the pressure of each compound in equilibrium.

If initial pressure of H2S is 3.00atm, concentrations in equilibrium are:

H2S = 3.00 atm - 2X

H2 = 2X

S2: = X

Replacing:

$3.2x10^{-7} = (2X)^2X / (3-2X)^2$

$3.2x10^{-7} = 4X^3 / 9- 6X+4X^2$

0 = 4X³ - 1.28x10⁻⁶X² + 1.92x10⁻⁶X - 2.88x10⁻⁶

Solving for X:

X = 0.008945 atm

As in equilibrium, pressure of S2 is X, pressure is 0.008945 atm

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2 years ago