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2 years ago

What are the representative elements usually called

Chemistry

1 answer:

antiseptic1488 [7]2 years ago

4 0

Answer:

There are two sets of groups in the periodic table. The first set are Group A elements and are also known as representative elements. The second set are Group B elements and are also known as transition metals. Representative elements are the most abundant elements on earth.

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Suppose that coal of density 1.5 g/cm^3 is pure carbon. (It is, in fact, much more complicated, but this is a reasonable first a

NISA [10]

Answer:

q = -6464.9 kJ

Explanation:

We are given that the heat of combustion is ∆H° = −394 kJ per mol of carbon.Therefore what we need to do is calculate how many moles of C are in the lump of coal by finding its mass since the density is given.

vol = 5.6 cm x 5.1 cm x 4.6 cm = 131.38 cm³

m = d x v = 1.5 g/cm³ x 131.38 cm³ = 197.06 g

mol C = m/MW = 197.06 g/ 12.01g/mol = 16.41 mol

q = −394 kJ /mol C x 16.41 mol C = -6464.9 kJ

7 0

3 years ago

A buret is filled with 0.1517 M A 25.0 mL portion of an unknown acid and two drops of indicator are added to an Erlenmeyer flask

erik [133]

Answer:

Molarity of Unknown Acid = 0.1332 M

Explanation:

Data for solving problem:

Molarity of base in buret (M₁)= 0.1517 M

volume of the acid in Erlenmeyer flask (V₂)= 25.0 mL

Volume of the base in the buret (V₁) = final volume of buret - initial volume in buret

final volume of buret = 22.5 mL

initial volume in buret = 0.55 mL

Volume of the base in the buret (V₁) = 22.5 mL -0.55 mL = 21.95 mL

Volume of the base in the buret (V₁) = 21.95 mL

Molarity of Unknown acid in the Erlenmeyer flask (M₂) = To be find

Explanation:

It is acid base titration and formula for this titration is as follows:

Molarity of base x Volume of base = Molarity of acid x volume of acid

it can be written as

M₁V₁ = M₂V₂ -------------------- equation (1)

we have to find M₂

so by rearrangment the equation (1)

M₁V₁ / V₂ = M₂ ------------------ equation (2)

put the values in equation in equation (2)

M₂ = 0.1517 M x 21.95 mL / 25.0 mL

M₂ = 3.3298 /25.0

M₂ = 0.1332 M

so the Molarity of Unknown acid is <u>0.1332 M</u>

5 0

3 years ago

What type of tectonic activity occurs in the San Andreas Fault?

kykrilka [37]

The answer is a strike-slip. More specifically a right-lateral strike-slip.

6 0

3 years ago

Determine the empirical formula for a compound that contains 15.8% carbon and 84.2% sulfer

nydimaria [60]

Answer:

Carbon Disulfide CS2

Explanation:

6 0

2 years ago

If the initial volume is 55ml and the final volume after some rocks of sandstone are added is 65ml what is the volume of the chi

AfilCa [17]

Answer:

Volume = 10ml

Density = 1/5 g/ml or 0.20g/ml

Explanation:

The rocks are 10ml since the initial volume went up by 10.

Since density = mass/volume, you divide 2 by 10.

D = 2/10

D = 1/5 g/ml or 0.20g/ml

(Unit is g/ml aka grams/millileter)

7 0

2 years ago