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nataly862011 [7]
3 years ago
11

On a class trip to the coast, you and your lab partner find a rock in the spot marked in red on the diagram. You show your teach

er the rock and he tells you to try to figure out what kind of rock it is by the composition and the way it has formed. You and your partner examine the rock. You make a list of observations, written above. What is an obvious choice and why?
Chemistry
2 answers:
NNADVOKAT [17]3 years ago
8 0
Cause it’s is the same
Amiraneli [1.4K]3 years ago
6 0

Answer:

D-Obsidian: it is an igneous rock often found in coastal areas, quickly cooled lava from volcanoes.

Explanation:

Obsidian has no crystals because it cools so quickly: it is called natural glass.

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Discuss the effect of changing the flow tube radius on flow rate.
dmitriy555 [2]

Answer:

The flow rate of a tube is the volume of fluid flowing through the tube per unit time. The flowrate is proportional to the product of the velocity of the fluid through the tube, and the cross-sectional area of the tube.

That is

Q = AV

where

A is the area of the tube

V is the velocity of the tube

The cross-sectional area of the tube is proportional to the radius of the tube. From the above equation, we can deduce that if the velocity of the fluid flowing through the tube is held constant, the flowrate of the fluid through the tube will increase with an increase in the radius of the tube, and it will decrease with a decrease in the radius of the tube.

7 0
2 years ago
The ph of 0.015 m hno2 (nitrous acid) aqueous solution was measured to be 2.63. what is the value of pka of nitrous acid?
Licemer1 [7]
Nitrous acid<span> dissociates as follows:
</span>
HNO₂(s) ⇄ H⁺(aq) + NO₂⁻(aq) 
           
According to the equation, an acid constant has the following form:

Ka = [H⁺] × [NO₂⁻ ] / [HNO₂] 

From pH, we can calculate the concentration of H⁺ and NO₂⁻:

[H⁺] = 10^-pH = 10^-2.63 = 0.00234 M = [NO₂⁻]

Now, the acid constant can be calculated:

Ka = 0.00234 x 0.00234 / 0.015  = 3.66 x 10⁻⁴

And finally,

pKa = -log Ka = 3.44 


7 0
2 years ago
An organic compound is 61.5% C, 2.56% H and 35.9% N by mass. 2.00 grams of this gas is entered into a 300.0 mL flask and heated
pashok25 [27]

Answer:

C₄H₂N₂

Explanation:

First we<u> calculate the moles of the gas</u>, using PV=nRT:

P = 2670 torr ⇒ 2670/760 = 3.51 atm

V = 300 mL ⇒ 300/1000 = 0.3 L

T = 228 °C ⇒ 228 + 273.16 = 501.16 K

  • 3.51 atm * 0.3 L = n * 0.082atm·L·mol⁻¹·K⁻¹ * 501.16 K
  • n = 0.0256 mol

Now we<u> calculate the molar mass of the compound</u>:

  • 2.00 g / 0.0256 mol = 78 g/mol

Finally we use the percentages given to<em> </em><u>calculate the empirical formula</u>:

  • C ⇒ 78 g/mol * 61.5/100 ÷ 12g/mol = 4
  • H ⇒ 78 g/mol * 2.56/100 ÷ 1g/mol = 2
  • N ⇒ 78 g/mol * 35.9/100 ÷ 14g/mol = 2

So the empirical formula is C₄H₂N₂

6 0
3 years ago
What is the capillary rise of ethanol in a glass tube with a 0.1 mm radius if the surface tension of ethanol is 0.032Jm2 and the
iragen [17]

Answer:

Explanation:

Expression for capillary rise is as follows

h = 2T / ρ g r where T is surface tension , ρ is density of liquid and r is radius of capillary tube.

T = .032 J m⁻²

ρ = .71 g / cm³

= 7100 kg / m³

r = .1 x 10⁻³ m = 10⁻⁴ m

h = 2 x .032 / (7100 x 9.8 x 10⁻⁴ )

h = .0092 m

= 9.2 mm .

5 0
2 years ago
How is this SI unit of temperature related to the metric unit of Celsius?
shtirl [24]

Answer:

Celsius is currently a derived unit for temperature in the SI system, kelvin being the base unit. ... The two main reference points of the Celsius scale were the freezing point of water (or melting point of ice) being defined as 0 °C and the boiling point of water being 100 °C.

Explanation:

Hope it helps

3 0
3 years ago
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