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3 years ago

(50 POINTS!)

Chemistry

2 answers:

aleksandrvk [35]3 years ago

7 0

Answer:

Can I get my 50 points now?

Explanation:

The helium is formed during the natural radioactive decay of elements such as uranium and thorium. These heavy elements were formed before the earth but they are not stable and very slowly, they decay. One mode of decay for uranium is to emit an alpha-particle.

nasty-shy [4]3 years ago

4 0

The sun converts hydrogen atoms into helium.

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If you looked at a glass containing a solution and a glass containing a suspension, how could you tell which glass contained the

marin [14]

Over time, the particles in the suspension would settle to the bottom when the movement keeping them suspended fades away. This will not happen with a solution.

6 0

3 years ago

Give below are the four mixtures. Choose the correct one which can be separated by winnowing. (i) soybean and chickpeas (ii) whe

victus00 [196]

Answer:

Banana wafers and chips

Explanation:

Winnowing is the process of separating heavier and lighter components of a mixture by blowing air through the mixture. This implies that the relative weight of the particles in the mixture determines whether they can be separated by winnowing or not.

However, chips are heavier than wafers. wafers refer to a very light snack which is easily blown away by a current of air. Hence banana chips and wafers can be separated using the method of winnowing.

4 0

3 years ago

When hydrogen sulfide gas is bubbled into a solution of sodium hydroxide, the reaction forms sodium sulfide and water. How many

Mumz [18]

Answer:

1.61 g Na₂S

Explanation:

To find the mass of sodium sulfide (Na₂S) generated from hydrogen sulfide (H₂S) and sodium hydroxide (NaOH), you need to (1) construct the balanced chemical equation, then (2) calculate the molar masses of each molecule involved, then (3) convert grams of each reagent to grams of the product (via the molar masses and mole-to-mole ratio from equation coefficients), and then (4) determine the limiting reagent and final answer. It is important to arrange the conversions in a way that allows for the cancellation of units (the desired unit should be in the numerator).

(Step 1)

The unbalanced equation:

H₂S + NaOH ---> Na₂S + H₂O

Reactants: 3 hydrogen, 1 sulfur, 1 sodium, 1 oxygen

Products: 2 hydrogen, 1 sulfur, 2 sodium, 1 oxygen

The balanced equation:

H₂S + 2 NaOH ---> Na₂S + 2 H₂O

Reactants: 4 hydrogen, 1 sulfur, 2 sodium 2 oxygen

Products: 4 hydrogen, 1 sulfur, 2 sodium, 4 oxygen

(Step 2)

Molar Mass (H₂S): 2(1.008 g/mol) + 32.065 g/mol

Molar Mass (H₂S): 34.081 g/mol

Molar Mass (NaOH): 22.990 g/mol + 15.998 g/mol + 1.008 g/mol

Molar Mass (NaOH): 39.998 g/mol

Molar Mass (Na₂S): 2(22.990 g/mol) + 32.065 g/mol

Molar Mass (Na₂S): 78.045 g/mol

(Step 3)

1.50 g H₂S 1 mole 1 mole Na₂S 78.045 g
----------------- x ---------------- x -------------------- x ----------------- =
34.081 g 1 mole H₂S 1 mole

= 3.43 g Na₂S

1.65 g NaOH 1 mole 1 mole Na₂S 78.045 g
-------------------- x ---------------- x ----------------------- x ---------------- =
39.998 g 2 moles NaOH 1 mole

= 1.61 g Na₂S

(Step 4)

Because NaOH generates less product, it will run out before all of the H₂S is used. This makes NaOH the limiting reagent and the final answer 1.61 grams Na₂S.

5 0

2 years ago

Anthracite is so hard and pure it is also referred to as a _____.

Serga [27]

Anthracite is also referred to as hard coal because it is so hard and pure. It is very hard and highly compacted with variety of coal that has submetallic luster. It has highest carbon content, the lowest impurities, and highest density of energy of all the coal deposits.

6 0

3 years ago

Define electronegativity

stira [4]

Answer: Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.

Explanation: Hope this helps!

6 0

3 years ago