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Rasek [7]
3 years ago
9

A large bar of solid gold is melted into liquid. The liquid is then poured into molds to make a number of gold coins. Was this a

chemical or physical change? Explain
Chemistry
1 answer:
Kobotan [32]3 years ago
8 0

Answer:

it's physical change because none of the components of the bar of solid have been tampered with so solid to liquid is physical change

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Can the ratio of hydrogen to oxygen change if a solute is dissolved in the water
coldgirl [10]

Answer:

Water molecules feature the combinations of hydrogen and oxygen atoms in a 2:1 ratio. Since they are present in a fixed ratio of mass, water molecules obey the law of constant proportions. Water is formed when two molecules of the diatomic hydrogen gas, combine with one molecule of the diatomic oxygen gas to produce two molecules of water

4 0
3 years ago
The titration of Na2CO3 with HCl has the following qualitative profile: a. Identify the major species in solution at points A-F.
exis [7]

Answer:

Answer is explained in the explanation section below.

Explanation:

Solution:

Note: This question is incomplete and lacks very important data to solve this question. But I have found the similar question which shows the profiles about which question discusses. Using the data from that question, I have solved the question.

a) We need to find the major species from A to F.

Major Species at A:

1. Na_{2} CO_{3}

Major Species at B:

1. Na_{2} CO_{3}

2. NaHCO_{3}

Major Species at C:

1. NaHCO_{3}

Major Species at D:

1. NaHCO_{3}

2. H_{2}CO_{3}

Major Species at E:

1. H_{2}CO_{3}

Major Species at F:

1. H_{2}CO_{3}

b) pH calculation:

At Halfway point B:

pH = pKa_{1} + log[CO_{3}.^{-2}]/[HCO_{3}.^{-1}]

pH = pKa_{1} = 6.35

Similarly, at halfway point D.  

At point D,

pH = pKa_{2} + log [HCO_{3}.^{-1}]/[H2CO_{3}]

pH = pKa_{2} = 10.33

8 0
3 years ago
Why it’s possible to walk through air but not a concrete wall
Sunny_sXe [5.5K]

well you can't walk through the air but you can't walk through a concrete wall because all of the solid atoms holding it together

3 0
4 years ago
According to the equation, 2 H2 + O2 --> 2 H20, how many moles of oxygen are required to convert 12 moles of hydrogen to wate
DerKrebs [107]

Answer:

6 moles of oxygen, or 3O2.

Explanation:

I would build a proportion for this:

\frac{2(2)}{2}  =  \frac{12}{x}  \\ 4x = 24 \\ x = 6

5 0
3 years ago
What is the name of the pores, or holes, on the outer layer of the sponge that take water in?
ivanzaharov [21]
The tiny holes in a sponges outer layer that take in water are called ostia, I believe. Hope it helps
7 0
4 years ago
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