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Maurinko [17]
3 years ago
15

A geologist determines that a sample of a mineral can't be scratched by a steel nail but can be scratched by a masonry drill bit

. Based on this information, the sample mineral has to be softer than A. orthoclase. B. fluorite. C. apatite. D. corundum.
Chemistry
2 answers:
MatroZZZ [7]3 years ago
7 0

Answer:

D. corundum.

Explanation:

Corundum is the hardest mineral in nature after diamond. For this reason it can only be scratched and worked by it. Mohs' hardness scale proves that corundum is indeed a very hard mineral and almost impossible to scratch. This scale states that the corundum has a hardness of 9.0, which indicates that it cannot be scratched by a drill.

Using the same scale, we can find out the hardness of the mineral exposed in the question. The mineral can be scratched by a drill, which means it has a hardness lower than 8.5, and the mineral cannot be scratched by a nail, which indicates that it has a hardness greater than 6.5. Based on this data, we can guarantee that this meniral is softer than the corundum.

KIM [24]3 years ago
4 0
D. Corundum

The mineral has a hardness greater than 6.5 (steel nail) and less than 8.5 (drill bit). All other choices have a hardness less than 8.5 but corundum has a hardness of 9.0. *Mohs hardness scale
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alukav5142 [94]

decameters - meters: multiply by 10

meters to meters: multiply by 1

centimeters to meters: divide by 100

millimeters to meters: divide by 1000

For the rows at the bottom:

hectometer row: 100, multiply by 100, 4500

decameter row: 10, multiply by 10, 450

meter row: 1, multiply by 1, 45

decimeter row: 0.1, divide by 10, 4.5

centimeter row: 0.01, divide by 100, 0.45

im guessing theres a millimeter row at the bottom:

millimeter row: 0.001, divide by 1000, 0.045


hope this helps!

5 0
3 years ago
Please help will reward brainliest
dimaraw [331]
The answer is most definitely “A”
7 0
3 years ago
→
marin [14]

Answer:

[A]²

Explanation:

Since the formation is independent of D, D is 0 order.

Since a quadruples when it is doubled it can be written as

2A^X= 4

To find the unknown power we can assume A= 1 to make the math simple. So When a = 2 (Because you doubled it) raised to X power it will equal 4

so the unknown power is 2

Making the rate law

[a]²[b]⁰

or simply just

[A]²

8 0
3 years ago
In an experiment, 132 grams of potassium bromide (KNO3) was dissolved in 100 grams of water at 70 °C in 1 minute. Which of the f
pishuonlain [190]
Answer: <span>A fewer number of particles of the sample will dissolve in 1 minute.

That is because normally the solubility and rate of solubility of the salts in water increase with the temperature. This is, the higher the temperature the higher and faster the number of particles that the water can dissolve. So, at 70°C more particles will be dissolved in water in 1 minute than at 20°C.
</span>
7 0
3 years ago
Read 2 more answers
The half life of 226/88 Ra is 1620 years. How much of a 12 g sample of 226/88 Ra will be left after 8 half lives?
Aloiza [94]

Answer:

0.0468 g.

Explanation:

  • The decay of radioactive elements obeys first-order kinetics.
  • For a first-order reaction: k = ln2/(t1/2) = 0.693/(t1/2).

Where, k is the rate constant of the reaction.

t1/2 is the half-life time of the reaction (t1/2 = 1620 years).

∴ k = ln2/(t1/2) = 0.693/(1620 years) = 4.28 x 10⁻⁴ year⁻¹.

  • For first-order reaction: <em>kt = lna/(a-x).</em>

where, k is the rate constant of the reaction (k = 4.28 x 10⁻⁴ year⁻¹).

t is the time of the reaction (t = t1/2 x 8 = 1620 years x 8 = 12960 year).

a is the initial concentration (a = 12.0 g).

(a-x) is the remaining concentration.

∴ kt = lna/(a-x)

(4.28 x 10⁻⁴ year⁻¹)(12960 year) = ln(12)/(a-x).

5.54688 = ln(12)/(a-x).

Taking e for the both sides:

256.34 = (12)/(a-x).

<em>∴ (a-x) = 12/256.34 = 0.0468 g.</em>

8 0
3 years ago
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