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tatyana61 [14]
3 years ago
5

A _________________ is developed through the scientific method, and it can be modified or improved upon. It may be represented b

y a model. As seen here, three different models were used to represent atomic structure as ideas changed over time. A) hypothesis B) law C) prediction D) theory
PLEASE HELP ME SOMEONE
Chemistry
1 answer:
hodyreva [135]3 years ago
5 0
The correct answer is D) Theory
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Predict the mass of iron (III) sulfide produced when 3.0 g of iron filings react completely with 2.5 g of yellow sulfur solid, S
777dan777 [17]
1) Chemical equation

16Fe(s) + 3S8(s) ---> 8Fe2S3

2) Molar ratios:

16 mol Fe : 3 mole S8 : 8 mol Fe2S3

3) Convert masses in grams to number of moles

number of moles = mass in grams / molar mass

a) iron, Fe

mass = 3.0 g
atomic mass = 55.845 g/mol

=> number of moles of Fe = 3.0g / 55.845 g/mol = 0.0537 mol

b) Sulfur, S8

mass = 2.5 g
molar mass = 8*32.065 g/mol = 256.52 g/mol

=> number of moles of S8 = 2.5g / 256.52 g/mol = 0.009746 mol

4) Limiting reactant

Theoretical ratio                           actual ratio

16 mol Fe / 3 mol S8                 0.0537 mol Fe / 0.009746 mol S8

5.33                                               5.50

So, there is a little bit more Fe than the theoretical needed to react all the S8, which means the S8 is the limiting reactant.

5) Calculate the number of moles of iron (III) produced with 2.5 g (0.009746 moles) of S8

3moles S8 / 8 moles Fe2S3 = 0.009746 moles S8 / x

=> x = 0.009746 * 8 / 3 moles Fe2S3 = 0.026 moles Fe2S3

6) Convert 0.026 moles Fe2S3 into grams

mass in grams = number of moles * molar mass

molar mass of Fe2S3 = 207.9 g/mol

mass = 0.026 mol * 207.9 g/mol = 5.40 g

7) Answer: option D)




3 0
3 years ago
Read 2 more answers
1a. A researcher accidentally spilled some sand into his beaker containing crystalline compound X. Knowing what he did about mel
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Answer:

See explanation

Explanation:

Many organic compounds have low melting points. This is due to the fact that many of these compounds are non polar.

However, compound X is slightly polar but still has a melting point which is far less than that of sand composed of a high melting point inorganic material.

Since sand has a much higher melting point compared to compound X, the researcher need not be worried that sand was spilled into his beaker.

7 0
2 years ago
Which of the following describes a reference point?
Vitek1552 [10]

Answer:

A

Explanation:

i think the answer is A

5 0
4 years ago
Methane (CH4), is said to be the cleanest burning fossil fuel. When burned, it releases carbon dioxide gas and forms water. Usin
LiRa [457]

From the stoichiometry of the balanced reaction equation, the correct statement are;

  • For every 1 molecule of methane CH4 that reacts, 2 molecules of H2O are produced.
  • For every 20 grams of methane (CH4) that reacts, 40 grams of H2O are produced.
  • For every 200 moles of methane (CH4) that reacts, 400 moles of H2O are produced.

<h3>What is combustion?</h3>

The term combustion refers to the burning of fossil fuels for the purpose of energy production. The equation for reaction is CH4 + 2O2 ---> CO2 + 2H2O.

Using this equation as shown, the true statements are;

  • For every 1 molecule of methane CH4 that reacts, 2 molecules of H2O are produced.
  • For every 20 grams of methane (CH4) that reacts, 40 grams of H2O are produced.
  • For every 200 moles of methane (CH4) that reacts, 400 moles of H2O are produced.

Learn more about combustion: brainly.com/question/15117038

3 0
2 years ago
A thermometer having first-order dynamics with a time constant of 1 min is placed in a temperature bath at 100oF. After the ther
sveticcg [70]

Answer:

(a) See below

(b) 103.935 °F; 102.235 °F

Explanation:

The equation relating the temperature to time is

T = T_{0} + \Delta T\left (1 - e^{-t/\tau} \right )

1. Calculate the thermometer readings after  0.5 min and 1 min

(a) After 0.5 min

\begin{array}{rcl}T & = & T_{0} + \Delta T\left (1 - e^{-t/\tau} \right )\\ & = & 100 + 10\left (1 - e^{-0.5/1} \right )\\ & = & 100 + 10\left (1 - e^{-0.5} \right )\\ & = & 100 + 10 (1 - 0.6065)\\ & = & 100 + 10(0.3935)\\ & = & 100 + 3.935\\ & = & 103.935\,^{\circ}F\\\end{array}

(b) After 1 min

\begin{array}{rcl}T & = & T_{0} + \Delta T\left (1 - e^{-t/\tau} \right )\\ & = & 100 + 10\left (1 - e^{-1/1} \right )\\ & = & 100 + 10\left (1 - e^{-1} \right )\\ & = & 100 + 10 (1 - 0.3679)\\ & = & 100 + 10(0.6321)\\ & = & 100 + 6.321\\ & = & 106.321\,^{\circ}F\\\end{array}

2. Calculate the thermometer reading after 2.0 min

T₀ =106.321 °F

ΔT = 100 - 106.321 °F = -6.321 °F

  t = t - 1, because the cooling starts 1 min late

\begin{array}{rcl}T & = & T_{0} + \Delta T\left (1 - e^{-(t - 1)/\tau} \right )\\ & = & 106.321 - 6.321\left (1 - e^{-(2 - 1)/1} \right )\\ & = & 106.321 - 6.321\left (1 - e^{-1} \right )\\ & = & 106.321 - 6.321 (1 - 0.3679)\\ & = & 106.321 - 6.321 (0.6321)\\ & = & 106.321 - 3.996\\ & = & 102.325\,^{\circ}F\\\end{array}

3. Plot the temperature readings as a function of time.

The graphs are shown below.

6 0
3 years ago
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