Ask question

Ask question

All categories

Ksenya-84 [330]

3 years ago

14

Mount Rushmore national memory in South Dakota was carved out of grantie that formed from cooled magma what type of rock matches

this description

1 answer:

gulaghasi [49]3 years ago

7 0

Answer:

igneous rocks

Explanation:

igneous rocks forms from lava, such as obsidian, basalt, plumice, etc

You might be interested in

Why are physical properties such as hardness or cleavage useful to geologists when identify minerals?

nevsk [136]

Answer:

Physical properties are controlled by the mineral's chemical composition and atomic structure, this combination is distinct in each mineral.

Explanation:

Hello,

Since the physical properties depend on the mineral's chemical composition and the atomic structure (molecular arrangement), we can distinguish different minerals by measuring out hardness, cleavage and other properties in order to analyze their behavior under several conditions and subsequently use them in a particular application.

Best regards.

5 0

3 years ago

To what temperature in kelvin will a 2.3 L balloon have to be heated to expand to a volume of 400 L Assume the initial temperatu

olchik [2.2K]

Answer:

T₂ = 51826.1 K

Explanation:

Given data:

Initial Volume = 2.3 L

Final volume = 400 L

Initial temperature = 25 °C (25+ 273 = 298 K)

Final temperature = ?

Solution:

V₁/T₁ = V₂/T₂

T₂ = V₂ T₁/V₁

T₂ = 400 L . 298 K / 2.3 L

T₂ = 119200 K. L / 2.3 L

T₂ = 51826.1 K

7 0

3 years ago

Be sure to answer all parts. Find the pH during the titration of 20.00 mL of 0.1000 M triethylamine, (CH3CH2)3N (Kb = 5.2 × 10−4

Nataliya [291]

Answer:

(a) 10.62

(b) 2.82

(c) 1.95

Explanation:

The neutralization reaction in this question is

(CH3CH2)3N + HCl ⇒ (CH3CH2)3NH⁺ + Cl⁻

The problem can be solved by calculating the number of moles of triethylamine after addition of the portions of HCl. Since it is a weak base if it is not consumed completely, that is in excess we will have a buffer of a waek base. If its consumed completely the pH will be determined by the strong acid HCl.

The pOH for a buffer of a weak base is gven by

pOH = pKb + log [(CH3CH2)3NH⁺] / [(CH3CH2)3N]

(a) 11 mL of 0.100 M HCl

mol HCl = 0.011 L x 0.100 mol/L = 0.0011 mol HCl

mol (CH3CH2)3N reacted = 0.0011 mol

mol (CH3CH2)3NH⁺ produced = 0.0011 mol

mol (CH3CH2)3N initially = 0.020 L x 0.1000 mol/L 0.0020 mol

mol (CH3CH2)3N left = 0.0020 mol - 0.0011 = 0.0009 mol

pKb = - log Kb = - log (5.2 x 10⁻⁴) = 3.284

Now we can compute pOH,

pOH = 3.284 + log ( 0.0011 / 0.0009 ) = 3.37

pH = 14 - pOH = 14 - 3.37 = 10.62

(b) 20.60 mL HCl

mol HCl = 0.0206 L x 0.100 mol/L = 0.00206

mol (CH3CH2)3N consumed = 0.0020 mol

This is so because the acid will consume completely the 0.0020 mol of the weak base we had originally present.

Now the problem circumscribes to that of calculating the pH of the unreacted HCl

Total Vol = 0.0206 L + 0.02 L = 0.0406 L

mol HCl = 0.0206 L x .100 = 0.00206 mol

mol HCl left = 0.00206 mol - 0.0020 mol = 0.00006 mol

[HCl] = 0.00006 mol / 0.0406 L = 0.0015 M

Since HCl is a strong acid ( 100 % ionization) :

pH = - log [H⁺] = - log ( 0.0015 ) = 2.82

(c) We will compute the pH in the same way we did for part (b)

mol HCl = 0.025 L x 0.100 mol/L = 0.0025 mol

mol HCl left = 0.0025 mol - 0.0020 mol = 0.0005

Total Volume = 0.020 L + 0.025 L = 0.045 L

[HCl] = 0.0005 mol / 0.045 L = 0.111

pH = - log ( 0.111) = 1.95

3 0

3 years ago

How much energy is required to raise the temperature of 3kg of iron from 20 degrees Celsius to 25 degrees Celsius

Yuri [45]

Answer:

6750 J

Explanation:

The specific heat capacity of iron is 450 J/kg/K

Quantity of heat = mcθ; where m is the mass and c is the specific heat capacity and θ is the temperature change.

Therefore;

m = 3 kg, c = 450 J/kg/K and θ = 5°C

Quantity of heat = 3 × 450 × 5

<u>= 6150 Joules</u>

5 0

3 years ago

Assign an oxidation number to each element in the reaction. co(g) 2h2(g) → ch3oh(g) in co, the oxidation number of c is , and th

Andrei [34K]

The oxidation state is the number of electrons gained and donated. The oxidation state of C is +2, O is -2, H is 0, and in methanol, C is +1, H is +1, and O is -2.

<h3>What is the oxidation number?</h3>

The oxidation number denotes the number of electrons donated and gained after the bond formation. In general, the oxidation state of free elements is zero, and of hydrogen when the bond to non-metal is +1 and with metals is -1.

The chemical reaction is given as,

$\rm CO + 2H_{2} \rightarrow CH_{3}OH$

Here,

The oxidation number of carbon in carbon monoxide will be +2, and oxygen will be -2.

The oxidation number of hydrogen in dihydrogen will be zero, and in methanol, the oxidation number of carbon will be +1, hydrogen will be +1 and oxygen will be -2.

Therefore, the oxidation number of oxygen is -2 most of the time.

Learn more about oxidation numbers here:

brainly.com/question/16326344

7 0

2 years ago