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2 years ago

Which of the following is the best hypothesis?

2 answers:

8 0

B is correct

Which of the following is the best hypothesis?
OA. Physical changes are much less interesting to watch than
chemical changes.
B. If sodium carbonate is added to vinegar, the reaction will absorb
heat.
C. Tearing a piece of paper is an example of a physical change.
D. Some chemical reactions absorb heat, and others release heat.
SUBMIT
Help me y’all

DerKrebs [107]2 years ago

4 0

Answer:

B.) If sodium carbonate is added to vinegar, the reaction will absorb heat.

Explanation:

A.) is incorrect because this is not testable. Rather, it is just an opinion that cannot be proven correct or incorrect.

B.) is correct because this statement is testable. Tests need to be run to determine the accuracy of the statement.

C.) is incorrect because this statement explains something that does not need to be tested. It is an example of a physical change when one tears a piece of paper.

D.) is incorrect because this is already a true statement. It is obvious that not all reactions absorb/release heat. While tests could be run to further prove this statement true, it is already considered accurate.

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Do equal volumes of the same gas at the same temperature and pressure contain equal numbers of molecules (number of moles)?

tresset_1 [31]

Answer:Therefore, there must be a direct relationship between these volumes of gases and the number of molecules they contain. Avogadro's law says that: Equal volumes of different gaseous substances, measured under the same pressure and temperature conditions, contain the same number of molecules.

Explanation:I hope it works for you.

4 0

3 years ago

HELP PLEASE THE OTHER 'ANSWER' ISNT EVEN AN ANSWER!

hodyreva [135]

Answer:

most likely that (2) the replicated experiment was performed incorrectly.

Why, u ask? u dare question me:

1- The initial experiment invalidness cannot be proven.

2- the second answer is correct

3- Different labaratories does not effect the outcome, as long as the parameter and environment of the replicated experiment is the same as when the initial experiment was conducted.

4- Already knowing the data and errors would increase the precision of the replicated experiment.

5- Change in variables should still be in the objective (or purpose) of the experiment, thus, major difference in the outcome should not happen.

happy learning!

4 0

3 years ago

A 17.6-g sample of ammonium carbonate contains ________ mol of ammonium ions.

postnew [5]

These problems are a bit interesting. :)

First let's write the molecular formula for ammonium carbonate.

NH4CO3 (Note! The 4 and 3 are subscripts, and not coefficients)

17.6 gNH4CO3

Now to convert to mol of one of our substances we take the percent composition of that particular part of the molecule and multiply it by our starting mass. This is what it looks like using dimensional analyse.

17.6 gNH4CO3 * (Molar Mass of NH4 / Molar Mass of NH4CO3)

Grab a periodic table (or look one up) and find the molar masses for these molecules! Well. In this case I'll do it for you. (Note: I round the molar masses off to two decimal places)

NH4 = 14.01 + 4*1.01 = 18.05 g/mol
NH4CO3 = 14.01 + 4*1.01 + 12.01 + 3*16.00 = 78.06 g/mol

17.6 gNH4CO3 * (18.05 molNH4 / 78.06 molNH4CO3)
= 4.07 gNH4

Now just take the molar mass we found to convert that amount into moles!

4.07 gNH4 * (1 molNH4 / 18.05 gNH4) = 0.225 molNH4

4 0

2 years ago

Plz help i’m stuckkkk

scZoUnD [109]

Answer:

first

Explanation:

Assets = Equity + Liability. ...

Assets = Liabilities + Shareholder's Equity.

then ans will be in your feet it's east

3 0

3 years ago

(6 points) Calculate the maximum number of moles and grams of H2S that can form when 158 g of aluminum sulfide reacts with 131 g

Schach [20]

Answer:107.1 g, 124.1 g

Explanation:

The equation of the reaction is;

Al2S3(s) + 6H20(l) ----> 2Al(OH)3(s) + 3H2S(g)

Hence;

For Al2S3

Number of moles= reacting mass/molar mass

Number of moles = 158g/150gmol-1 =1.05 moles

If 1 mole of Al2S3 yields 3 moles of H2S

1.05 moles of Al2S will yield

1.05 × 3/1 = 3.15 moles

Mass of H2S = 3.15moles × 34 gmol-1 = 107.1 g

For water

Number of moles of water = 131g/18gmol-1= 7.3 moles

6 moles of water yields 3 moles of H2S

7.3 moles of water will yield 7.3 × 3/6 = 3.65 moles of H2S

3.65 moles × 34 gmol-1 =124.1 g

5 0

3 years ago