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denis23 [38]
2 years ago
8

Which is the most important question for deciding if a chemical reaction has occurred?

Chemistry
2 answers:
777dan777 [17]2 years ago
7 0

Answer:

all these are physical properties except release of heat so it's probably heat energy given off

navik [9.2K]2 years ago
4 0

Answer:Was any heat energy given off?

Explanation:

A chemical reaction may exothermic (heat is given off) or endothermic (heat is absorbed). Size, density or texture of the substance are strictly physical properties which cannot confirm that a chemical reaction has transpired in the sample. The evolution of heat ultimately confirms that a chemical process has taken place.

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Certain glass objects are not meant to be heated and could shatter if exposed to a heat source. What two examples of heat-sensit
Stels [109]

Answer: the heat-sensitive glassware that were given are : Volumetric and Graduated cylinder.

Explanation:glass material that reacts to ambient temperatures radiated off of other surfaces like hands or water is known as heat sensitive glassware. They are not meant to be heated and could shatter if exposed to a heat source. Examples from the video includes Volumetric and Graduated cylinder. Hope this helps. Thanks.

8 0
2 years ago
What mass of solid lead would displace exactly 234.6 liters of water?
eimsori [14]
Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions.

The mass of solid lead would displace exactly 234.6 liters of water should be <span>2,674,440</span>
6 0
2 years ago
Read 2 more answers
SEP Use Models Why does the number of electrons in each principal energy shell increase as the number of the shell increases?
zlopas [31]

Answer:

See explanation

Explanation:

The number of electrons in each principal energy shell increases as the number of shells increases because more electronic orbitals become available to accommodate the electrons.

For instance, the n= 2 level only accommodates eight electrons in the s and p orbitals whereas the n=3 level accommodates 18 electrons in s, p and d orbitals respectively.

Each principal level accommodates 2n^2 electrons where n= the principal energy shell.

4 0
1 year ago
A sample of thallium(III) peroxide, Tl2(O2)3, contains 2.45 mol of thallium(III) ions. The number of moles of peroxide ions in t
Naddika [18.5K]

Answer:

The correct answer is 3.675 moles.

Explanation:

Based on the question, the reaction taking place is,  

Tl₂(O₂)₃ ⇒ 2Tl⁺³ + 3O₂⁻²

Thus, 1 mole of thallium peroxide comprise 2 moles of thallium and 3 moles of peroxide ions.  

However, based on the given question, a sample of thallium peroxide comprise 2.45 moles of thallium ions. The moles of peroxide ions present in the sample will be,  

= 2.45 × 3 / 2

= 3.675 moles.  

Hence, the moles of peroxide ions present in the given sample is 3.675.  

7 0
2 years ago
How many grams of nano3 would you add to 500g of h2o in order to prepare a solution that is 0.500 molal in nano3?
VARVARA [1.3K]
When the concentration is expressed in molality, it is expressed in moles of solute per kilogram of solvent. Since we are given the mass of the solvent, which is water, we can compute for the moles of solute NaNO3.

0.5 m = x mol NaNO3/0.5 kg water
x = 0.25 mol NaNO3

Since the molar mass of NaNO3 is 85 g/mol, the mass is

0.25 mol * 85 g/mol = 21.25 grams NaNO3 needed
4 0
2 years ago
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