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3 years ago

Pumice is a lightweight rock that sometimes forms when lava is very rich in _____.

Chemistry

2 answers:

Oksi-84 [34.3K]3 years ago

3 0

Answer: gases

(has bubbles in the rock)

tatuchka [14]3 years ago

3 0

This question is incomplete. Here is the complete question:

Pumice is a lightweight rock that sometimes forms when lava is very rich in _____. A. silica B. gases C. feldspar D. volcanic glass

Answer:

The correct answer is option D. volcanic glass.

Explanation:

Pumice stone is a very common stone used for construction or cleaning among other things.

This rock is formed through lava that contains water and gas and comes from the inside of a volcano, so when this lava is thrown out of the volcano it cools and hardens, and is filled with bubbles of volcanic gas.

This type of rock is low density and can float on water.

Given this information we can say that the correct answer is the option D. volcanic glass

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Abiotic factors are no living part of an environment. True or False

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Answer:

true

Explanation:

abiotic means nonliving and biotic means living

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3 years ago

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Answer:

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3 years ago

"Compounds A and B react to give a single product, C. Write the rate law for each of the following cases and determine the units

olasank [31]

Answer:

Part a: Units of k is $M^{-2}s^{-1}$ where reaction is first order in A and second order in B

Part b: Units of k is $M^{-1}s^{-1}$ where reaction is first order in A and second order overall.

Part c: Units of k is $M^{-1}s^{-1}$ where reaction is independent of the concentration of A and second order overall.

Part d: Units of k is $M^{-3}s^{-1}$ where reaction reaction is second order in both A and B.

Explanation:

As the reaction is given as

$A+B \rightarrow C$

where as the rate is given as

$r=k[A]^x[B]^y$

where x is the order wrt A and y is the order wrt B.

Part a:

x=1 and y=2 now the reaction rate equation is given as

$r=k[A]^1[B]^2$

Now the units are given as

$r=k[A]^1[B]^2\\M/s =k[M]^1[M]^2\\M/s =k[M]^{1+2}\\M/s =k[M]^{3}\\M^{1-3}/s =k\\M^{-2}s^{-1} =k$

The units of k is $M^{-2}s^{-1}$

Part b:

x=1 and o=2

x+y=o

1+y=2

y=2-1

y=1

Now the reaction rate equation is given as

$r=k[A]^1[B]^1$

Now the units are given as

$r=k[A]^1[B]^1\\M/s =k[M]^1[M]^1\\M/s =k[M]^{1+1}\\M/s =k[M]^{2}\\M^{1-2}/s =k\\M^{-1}s^{-1} =k$

The units of k is $M^{-1}s^{-1}$

Part c:

x=0 and o=2

x+y=o

0+y=2

y=2

Now the reaction rate equation is given as

$r=k[A]^0[B]^2$

Now the units are given as

$r=k[B]^2\\M/s =k[M]^2\\M/s =k[M]^{2}\\M^{1-2}/s =k\\M^{-1}s^{-1} =k$

The units of k is $M^{-1}s^{-1}$

Part d:

x=2 and y=2

Now the reaction rate equation is given as

$r=k[A]^2[B]^2$

Now the units are given as

$r=k[A]^2[B]^2\\M/s =k[M]^2[M]^2\\M/s =k[M]^{2+2}\\M/s =k[M]^{4}\\M^{1-4}/s =k\\M^{-3}s^{-1} =k$

The units of k is $M^{-3}s^{-1}$

7 0

3 years ago

A cylindrical glass tube of length 27.4cm and radius 4 cm is filled with gas. The empty tube has a mass of 254.3 g. The tube fil

Temka [501]

Density of the gas is 3.05 × 10⁻³ g / cm³.

Explanation:

Volume of the cylinder = π r² h

where r is the radius and h is the height of the height or the length of the glass tube.

Here r = 4 cm and h = 27.4 cm

Volume of the cylinder = 3.14 × 4 × 4 × 27.4 = 1376.6 cm³

We have to find the mass of the gas by subtracting the mass of the tube filled with the substance from the mass of the empty tube.

Mass of the substance = 258.5 - 254.3 = 4.2 g

We have to find the density using the formula as,

$$ Density = \frac{mass}{volume}$

Plugin the values as,

$$ Density = \frac{4.2}{1376.6}$

= 3.05 × 10⁻³ g / cm³

So the Density of the gas is 3.05 × 10⁻³ g / cm³.

3 0

3 years ago

A gaseous mixture contains 5.0 moles of nitrogen and 10.0 moles of helium . What is the total pressure if the temperature is 25

jolli1 [7]

Answer:

A) 122 atm

Explanation:

PV = nRT

Solve for P --> P = nRT/V

n = 10.0 mol + 5.0 mol = 15.0 mol

R = 0.08206 L atm / mol K

T = 25 + 273 = 298 K

V = 3.0

P = (15.0)(0.08206)(298) / (3.0) = 122 atm

6 0

3 years ago