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kotykmax [81]
3 years ago
5

20. Which of the following are pure substances?

Chemistry
1 answer:
Juliette [100K]3 years ago
3 0
The answer is III and V
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A 155g sample of copper was heated to 150.0 degrees Celsius, then placed into 250.0g water at 19.8 degrees Celsius. Calculate th
bogdanovich [222]
Once for the water and once for the copper. Set up a table that accounts for each of the variables you know, and then identify the ones you need to obtain. Give me a moment or two and I will work this out for you.

Okay, so like I said before, you will need to use the equation twice. Now, keep in mind that when the copper is placed in the water (the hot into the cold), there is a transfer of heat. This heat transfer is measured in Joules (J). So, the energy that the water gains is the same energy that the copper loses. This means that for your two equations, they can be set equal to each other, but the copper equation will have a negative sign in front to account for the energy it's losing to the water.

When set equal to each other, the equations should resemble something like this:
(cmΔt)H20 = -(cmΔt)Cu
(Cu is copper).

Remember, Δt is the final temperature minus the initial temperature (T2-T1). We are trying to find T2. Since we are submerging the copper into the water, we can assume that the final temperature at equilibrium is the same for both the copper and the water. At a thermodynamic equilibrium, there is no heat transfer because both materials are at the same temperature.

T2Cu = T2H20

Now, the algebra for this part of the problem is a bit confusing, so make sure you keep track of your variables. If done right, the algebra should work out so you have this:

T2 = ((cmT1)Cu + (cmT1)H20) / ((cm)H20 + (cm)Cu)
Insert the values for the variables. Once you plug and chug, your final answer should be
26.8 degrees Celsius.
3 0
3 years ago
What best explains why sodium is more likely to react with another element than an element such as neon?
hichkok12 [17]

Answer:

1 fewer electron

Explanation:

5 0
3 years ago
Read 2 more answers
Calculate the ratio of the velocity of helium atoms to the velocity of neon atoms at the same temperature.
o-na [289]

Answer:

vHe / vNe = 2.24

Explanation:

To obtain the velocity of an ideal gas you must use the formula:

v = √3RT / √M

Where R is gas constant (8.314 kgm²/s²molK); T is temperature and M is molar mass of the gas (4x10⁻³kg/mol for helium and 20,18x10⁻³ kg/mol for neon). Thus:

vHe = √3×8.314 kgm²/s²molK×T / √4x10⁻³kg/mol

vNe = √3×8.314 kgm²/s²molK×T / √20.18x10⁻³kg/mol

The ratio is:

vHe / vNe = √3×8.314 kgm²/s²molK×T / √4x10⁻³kg/mol / √3×8.314 kgm²/s²molK×T / √20.18x10⁻³kg/mol

vHe / vNe = √20.18x10⁻³kg/mol / √4x10⁻³kg/mol

<em>vHe / vNe = 2.24</em>

<em />

I hope it helps!

8 0
3 years ago
What are three types of subatomic particles
saw5 [17]

protons, neutrons, and electrons.

8 0
3 years ago
Scientists use what properties to help them identify and classify matter
Volgvan
Scientists use the physical and chemical properties to help them identify and classify matter. These physical and chemical properties are in a macro-perspective, in which these matter contains compounds, elements and atoms. Hence, matter can be classified in various ways, <span><span>
1.    </span>Atomic number either atomic mass each element has</span> 
<span><span>2.    </span>By substance of that matter either pure substance or mixed substance</span> <span>
3.    If they cannot reduce a certain substance into a much smaller quantified atomic structure then they they’ll use (2) to identify and classify it.</span>
5 0
3 years ago
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