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Alla [95]
4 years ago
7

HURRY PLEASE! True or false: Making an observation is the first step of the scientific method.

Chemistry
1 answer:
lions [1.4K]4 years ago
8 0

Answer:

True

Explanation:

You must first observe your data then form a hypothesis.

You might be interested in
Calculate the change in entropy when 10.0 g of CO2 isothermally expands from a volume of 6.15 L to 11.5 L. Assume that the gas b
USPshnik [31]

Answer:

The change in entropy of the carbon dioxide is 1.183\times 10^{-3} kilojoules per Kelvin.

Explanation:

By assuming that carbon dioxide behaves ideally, the change in entropy (\Delta S), measured in kilojoules per Kelvin, is defined by the following expression:

\Delta S = m\cdot \bar c_{v}\cdot \ln \frac{T_{f}}{T_{o}}+m\cdot \frac{R_{u}}{M}\cdot \ln \frac{V_{f}}{V_{o}} (1)

Where:

m - Mass of the gas, measured in kilograms.

\bar c_{v} - Isochoric specific heat of the gas, measured in kilojoules per kilogram-Kelvin.

T_{o}, T_{f} - Initial and final temperatures of the gas, measured in Kelvin.

V_{o}, V_{f} - Initial and final volumes of the gas, measured in liters.

R_{u} - Ideal gas constant, measured in kilopascal-cubic meter per kilomole-Kelvin.

M - Molar mass, measured in kilograms per kilomole.

If we know that T_{o} = T_{f}, m = 0.010\,kg, R_{u} = 8.315\,\frac{kPa\cdot m^{3}}{kmol\cdot K}, M = 44.010\,\frac{kg}{kmol}, V_{o} = 6.15\,L and V_{f} = 11.5\,L, then the change in entropy of the carbon dioxide is:

\Delta S = \left[\frac{ (0.010\,kg)\cdot \left(8.315\,\frac{kPa\cdot m^{3}}{kmol\cdot K} \right)}{44.010\,\frac{kg}{kmol} } \right]\cdot \ln \left(\frac{11.5\,L}{6.15\,L}\right)

\Delta S = 1.183\times 10^{-3}\,\frac{kJ}{K}

The change in entropy of the carbon dioxide is 1.183\times 10^{-3} kilojoules per Kelvin.

4 0
3 years ago
Question 23 (5 points)
iren [92.7K]

Answer:

λ = 6.25 × 10⁻¹⁰ m

x-ray

General Formulas and Concepts:

Speed of Light = Wavelength times Frequency

  • c = λν

Explanation:

<u>Step 1: Define</u>

C = 3.0 × 10⁸ m/s

ν  = 4.80 × 10¹⁷ Hz (s⁻¹)

λ = unknown

<u>Step 2: Solve for wavelength</u>

3.0 × 10⁸ m/s = λ(4.80 × 10¹⁷ Hz)

λ = 6.25 × 10⁻¹⁰ m

<u>Step 3: Check</u>

<em>We are given 3 sig figs. Follow sig fig rules.</em>

6.25 has 3 sig figs. No changes necessary.

<u>Step 4: Identify</u>

6.25 × 10⁻¹⁰ m is in the x-ray spectrum according the the Electromagnetic Spectrum

5 0
3 years ago
A rock that has a mass if 180 grams dropped in a graduated cylinder that was originally filled to 52ml; it now reads 62ml. What
Vlad [161]

Answer:

<h2>18 g/mL</h2>

Explanation:

The density of a substance can be found by using the formula

density =  \frac{mass}{volume} \\

volume = final volume of water - initial volume of water

volume = 62 - 52 = 10 mL

From the question we have

density =  \frac{180}{10}  \\

We have the final answer as

<h3>18 g/mL</h3>

Hope this helps you

5 0
3 years ago
What experiment did J. J. Thomson do?
scoundrel [369]

Answer:

A. He sent a cathode ray between electrically charged metal plates

5 0
4 years ago
What is the mass in kilograms of an object that weighs 50.0lbs?
Aleonysh [2.5K]

The amount of matter in an object is said to be its mass. The SI base unit of mass is kilograms i.e. kg.

The mass of the object = 50.0 lbs (given)

For converting lbs to kg:

1 lb = 0.453592 kg

So, 50 lbs = 50\times 0.453592 kg = 22.6796 kg \simeq 22.68 kg

Hence, the mass of 50.0lbs object in kilograms is 22.68 kg.

5 0
3 years ago
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