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nekit [7.7K]
3 years ago
6

A reaction occurs in a calorimeter that heats up 15g water from 25 oC to 50 oC. The specific heat of water is 4.184 J/goC. Deter

mine the thermal energy (Q) that must have entered the water to produce this temperature change.
Chemistry
1 answer:
Anit [1.1K]3 years ago
7 0

The thermal energy (Q) needed : = 1882.8 J

<h3>Further explanation</h3>

Given

15g water from 25 °C to 50 °C

Required

The thermal energy (Q)

Solution

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  

∆T = temperature difference, ° C / K  

Input the value :

Q = 15 g x 4.184 J/g°C x (50 °C- 20 °C)

Q = 1882.8 J

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I NEED HELP PLEASE! :)
riadik2000 [5.3K]

Answer:

C_{21} H_{23} NO_{5}

Explanation:

First thing is we have assume all the percents are grams so we have

68.279g C, 6.2760g H, 3.7898g N, and 21.656g O

Now convert each gram to moles by dividing the the molar mass of each element

68.279g/12.01g= 5.685 moles of C

6.2760g/1.01g= 6.214 moles of H

3.7898g N/14.01g= 0.271 moles  of N

21.656g O/ 16.00g= 1.354 moles of O

Now to find the lowest ratios divide all the moles by the smallest number of moles you found, in our case, the smallest moles is 0.271 moles of N so divide everything by that....

5.685 moles/0.271 moles ------> ~21 C

6.214 moles/0.271 moles --------> ~23 H

0.271 moles  / 0.271 moles  ---------> 1 N

1.354 moles/ 0.271 moles ----------> ~5 O

So the empirical formula is C21H23NO5 C_{21} H_{23} NO_{5}

5 0
3 years ago
The ads informs you of the proper first aid actions needed in case of exposure to chemical
Mice21 [21]

Answer:

im guessing false

Explanation:

7 0
3 years ago
How many unpaired electrons are present in the ground state of a phosphorus atom? a. 3 0.0
inessss [21]

Answer:

3

Explanation:

You need to remember that to measure the number of unparied electrons in an atom you need to undestard its electron configuration, and the electron configuration of phosphorus is 1s2 2s2 2p6 3s2 3p3, just the last state "3p3" have unpaired electron, and because a p state can fits 6 electrons, and here are only 3, that means that those 3 are unpaired.

6 0
4 years ago
You notice something is growing in a 100ml pot of liquid soap. You take 1ml of this liquid soap and perform a serial dilution an
andrew-mc [135]

Answer:

3'700,000 cfu

Explanation:

One way to count the amount of bacteria in a medium is by doing a dilution of the sample and count how many colonies growth. Each colony is a cfu (Colony forming units).

In the problem, you count 37 colonies. The dilution was 1:100,000. That means the bacteria present in the soap is:

37 colonies × (100,000 / 1) = <em>3'700,000 cfu</em>

<em></em>

I hope it helps!

6 0
3 years ago
If xenon has an atomic number of 54 and a mass number of 108, how many neutrons does it have?
vladimir2022 [97]

1. The atomic number is equal to the number of protons in the nucleus, and the mass number is equal to the number of protons and neutros in the nucleus.

Therefore, to find the number of neutrons we must do mass number - atomic number, which equals 54.

Answer 1: a. 54

2. Atoms of a same element that have a different number of neutrons in the nucleus are called isotopes of an element.

Answer 2: d. Isotopes

3. Potassium has an electron configuration of [Ar] 4s^{1}, meaning that the first 3 shells are full, and that the last shell (4th one) has only 1 electron.

Answer 3: c. Shells 1, 2 and 3 are full and shell 4 has one electron.

4. An atomic bond isn't a specific bond, it's just a term. Polar covalent and non-polar covalent bonds are strong bonds, which leaves us with the hydrogen bonds, which are indeed the weakest bonds out there.

Answer 4: a. Hydrogen bond

Hope it helped,

BiologiaMagister

5 0
4 years ago
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