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Aliun [14]
3 years ago
14

If a metal changes color over time from exposure to air, what has likely occurred?

Chemistry
1 answer:
natita [175]3 years ago
3 0

Answer:

Option A. a chemical change

Explanation:

A chemical change is a change in which new substance is formed and can not be easily reversed. A change of metal color when exposed to air for a long time is simply called rusting. This is a chemical change as new substance is formed. This can be seen when Zn roofing sheets changes color over time on exposure to air.

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9. Which of the following is true?
wlad13 [49]
The answer should be C
6 0
3 years ago
7. How many formula units are equal to a 0.25 g sample of Chromium (III) sulfate,
ryzh [129]

Answer:

38.541 × 10¹⁹ formula units

Explanation:

Given data:

Mass of chromium sulfate = 0.25 g

Formula units in 0.25 g = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ formula units of water

Number of moles of chromium sulfate =  Mass / molar mass

Number of moles of chromium sulfate = 0.25 g/ 392.16 g/ mol

Number of moles of chromium sulfate = 6.4 × 10⁻⁴ moles

Number of formula units:

1 mole = 6.022 × 10²³ formula units

6.4 × 10⁻⁴ moles × 6.022 × 10²³ formula units / 1 mol

38.541 × 10¹⁹ formula units

7 0
3 years ago
How many milliliters of sterile water for injection should be added to a vial containing 5 mg/mL of a drug to prepare a solution
jonny [76]

Answer:

7mL of sterile water is the initial amount of the concentrated solution is 3mL

Explanation:

In this problem, the vial must be <em>diluted </em>from 5mg/mL to 1.5mg/mL, that means the solution must be diluted:

5mg/mL / 1.5mg/mL = 3.33 times

If the initial amount of the drug in the vial is 3mL, the final volume must be:

10mL

That means the volume of water that should be added is:

10mL - 3mL:

<h3>7mL of sterile water is the initial amount of the concentrated solution is 3mL</h3>
4 0
3 years ago
Pleasee help <br> will name brainliest
zmey [24]

Answer:

0.125. work- divide the volume value by 1000

873. work- multiply the length value by 100

98100. work- Conversion factor: 1 kg = 100000 cg

1) Centigram = Kilogram * 100000

2) Centigram = 0.981 * 100000

3) Centigram = 98100

285.65. work- 12.5°C + 273.15 = 285.65K

446.85. work- 720K − 273.15 = 446.85°C

346.25. work- 73.1°C + 273.15 = 346.25K

Explanation:

i hope this helps:)  brainliest plss??

8 0
3 years ago
A student who is performing this experiment pours an 8.50 mL sample of the saturated borax solution into a 10 mL graduated cylin
belka [17]

Answer:

Ksp = 0.1762

Explanation:

Applying

a) moles of HCl added, n= CV=0.5×0.012 = 6×10-3mol

b) since 0.006mol is present in 0.012dm3 of HCl

It implies moles of borax

C) Concentration = 0.706M

Ksp = [0.5]^2[0.706]= 0.176

6 0
3 years ago
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