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3 years ago

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Chemistry

1 answer:

Nadya [2.5K]3 years ago

6 0

Answer:

D. Protons ; neutrons.

Explanation:

For a given element the number of protons is fixed, but the number of neutrons differ because the element usually consist of a number of isotopes.

For example Carbon has isotopes which contain 12, 13 and 14 neutrons.

So that is why you average the number of neutrons to find the approximate atomic mass..

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Which of the following has the most atoms per mole?

BabaBlast [244]

Answer:

e) Na₃PO₄

Explanation:

a) BaSO₄

1 mole of BaSO ₄ = 6.022×10²³ molecules

1 mole of BaSO ₄ contain 1 atom of Ba one atom of S and four atoms of O.

Total number of atoms = 6 atoms

6.022×10²³ × 6 atoms = 36.132 ×10²³ atoms

b) NaNO₂

1 mole of NaNO₂= 6.022×10²³ molecules

1 mole of NaNO₂ contain 1 atom of Na one atom of N and two atoms of O.

Total number of atoms = 4 atoms

6.022×10²³ × 4 atoms = 24.088 ×10²³ atoms

c)KMnO₄

1 mole of KMnO₄ = 6.022×10²³ molecules

1 mole of KMnO₄ contain 1 atom of K one atom of Mn and four atoms of O.

Total number of atoms = 6 atoms

6.022×10²³ × 6 atoms = 36.132 ×10²³ atoms

d) KCl

1 mole of KCl = 6.022×10²³ molecules

1 mole of KCl contain 1 atom of K one atom of Cl.

Total number of atoms = 2 atoms

6.022×10²³ × 2 atoms = 12.044 ×10²³ atoms

e) Na₃PO₄

1 mole of Na₃PO₄ = 6.022×10²³ molecules

1 mole of Na₃PO₄ contain 3 atom of Na one atom of P and four atoms of O.

Total number of atoms = 8 atoms

6.022×10²³ × 8 atoms = 48.176×10²³ atoms

3 0

3 years ago

Determine the mass of water in kg, if 4300 cal of energy is placed in water, resulting in a temperature change to 101.0 oC from

Airida [17]

Answer:

0.5059kg

Explanation:

The heat absorbed for the water is determined using the equation:7

Q = C×m×ΔT

Where Q is heat absorbed (4300cal)

C is specific heat (1cal/g°C)

m is the mass in grams

ΔT is change in °C (101.0°C - 92.5°C = 8.5°C)

Replacing:

4300cal = 1cal/g°C×m×8.5°C

505.9g = m

In kg, the mass of water is:

6 0

3 years ago

Compare the keys to periodic tables a and b to the key to the periodic table in your textbook. what other information is provide

lesya692 [45]

What the definition of each period and group and element and every valence electron

5 0

3 years ago

List all the physical properties of the iceberg.

Semmy [17]

Answer: My answer is in the explanation

Explanation:

Physical and mechanical characteristics of iceberg ice were studied from samples collected near the shores of eastern Newfoundland. Although the physical characteristics show considerable diversity, iceberg ice has some common features and is generally porous, lacks significant concentrations of dissolved materials, contains internal cracks and has an irregular interlocking grain structure.

3 0

3 years ago

Zinc reacts with hydrochloric acid according to the reaction equation Zn ( s ) + 2 HCl ( aq ) ⟶ ZnCl 2 ( aq ) + H 2 ( g ) How ma

REY [17]

Answer:

34.7mL

Explanation:

First we have to convert our grams of Zinc to moles of zinc so we can relate that number to our chemical equation.

So: 6.25g Zn x (1 mol / 65.39 g) = 0.0956 mol Zn

All that was done above was multiplying the grams of zinc by the reciprocal of zincs molar mass so our units would cancel and leave us with moles of zinc.

So now we need to go to HCl!

To do that we multiply by the molar coefficients in the chemical equation:

$\frac{0.0956g Zn}{1 } (\frac{2 mol HCl}{1molZn})$

This leaves us with 2(0.0956) = 0.1912 mol HCl

Now we use the relationship M= moles / volume , to calculate our volume

Rearranging we get that V = moles / M

Now we plug in: V = 0.1912 mol HCl / 5.50 M HCl

V= 0.0347 L

To change this to milliliters we multiply by 1000 so:

34.7 mL

7 0

3 years ago