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4 years ago

HELP ME WITH THIS. I'M BEING TIMED

Chemistry

1 answer:

telo118 [61]4 years ago

3 0

Answer: D. Theories are refined as new scientific information is discovered.

Explanation: New evidence might alter a theory’s accuracy while not necessarily making it absolutely untrue.

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Which of the following best describes a vacuum? Hot Cold Shiny Empty

wel

Answer:

shiny

Explanation:

4 0

3 years ago

Read 2 more answers

Please Help!!! Time LImit. Extra Points and Brainiest.

evablogger [386]

Answer:

A and D

Explanation:

8 0

3 years ago

A solar heating specialist is considering paraffin (Cp = 2.90 J/g O C) as a storage material for heat. How many kg of paraffin w

Stels [109]

Answer:

Mass of paraffin that would be needed to collect the amount of energy as 4.73 x 10³ kg of water is 6.85 * 10³ kg

Explanation:

Specific heat capacity of paraffin, Cp = 2.90 J/g.°C = 2900 J/kg.°C

Specific heat capacity of water = 4.20 J/g.°C = 4200 J/kg.°C

Amount of heat energy that can be stored by 4.73 * 10³ kg of water heated through a degree rise in temperature can be calculated as below:

Using H = mCpθ where m is mass of substance, Cp is specific heat capacity and θ is temperature change

H = 4.73 * 10³ kg * 4200 J/kg.°C * 1°C

H = 19866000 J

Mass of paraffin that would be needed to collect the amount of energy as 4.73 x 10 3 kg of water for a degree rise in temperature is calculated as follows:

H = mCpθ

19866000J = m * 2900 J/kg.°C * 1°C

m = 19866000J / 2900 J/kg

m = 6850.34 kg = 6.85 * 10³ kg

Therefore, mass of paraffin that would be needed to collect the amount of energy as 4.73 x 10³ kg of water is 6.85 * 10³ kg

7 0

3 years ago

A 13.00 g sample of a compound contains 4.15 g potassium (k), 3.76 g chlorine (cl), and oxygen (o). calculate the empirical form

MrRissso [65]

To solve this problem, let us all convert the mass of each element into number of moles using the formula:

moles = mass / molar mass

Where,

molar mass K = 39.10 g / mol

molar mass Cl = 35.45 g / mol

molar mass O = 16 g / mol

and mass O = 13 g – 4.15 g – 3.76 g = 5.09 g

moles K = 4.15 g / (39.10 g / mol) = 0.106 mol

moles Cl = 3.76 g / (35.45 g / mol) = 0.106 mol

moles O = 5.09 g / (16 g / mol) = 0.318 mol

The ratio becomes:

0.106 K: 0.106 Cl: 0.318 O

We divide all numbers with the smallest number, in this case 0.106. This becomes:

K: Cl: 3O

Therefore the empirical formula is:

$KClO_{3}$

7 0

3 years ago

A compound containing only carbon, hydrogen, and oxygen is analyzed and found to have the exact same percentage of carbon as it

Wittaler [7]

Answer:

Explanation:

Since we aren't told the mass of material we have, let's assume the boss was generous, and precise, and we have 100.00 grams of the mystery compound. We are told only that hydrogen is 5.988% and that the only other two elements are carbon and oxygen, with equal percentages. (100%-5.988%)/2 = 47.006% of each. See the attached table.

We now have the number of grams of each element, so let's convert that into moles of each by dividing the mass by the element's molar mass, The result in the table is

Moles

C 3.91

H 5.99

O 2.94

We need whole numbers for the empirical formula, so round to C4H6O3, the empirical formula. Possibly acetoacetic acid, a metabolite.

8 0

2 years ago