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4 years ago

Which statement accurately compares the trends in atomic number and atomic mass in the periodic table?

Chemistry

2 answers:

TiliK225 [7]4 years ago

8 0

Answer:

C. Both the atomic mass and the atomic number increase from left to right.

Explanation:

Dmitriy789 [7]4 years ago

7 0

The answer is , C. Both the atomic mass and the atomic number increase from left to right .

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Based on the tiles shown, how many moles of oxygen gas (o2) are needed to produce 36.04 grams of water (h2o) when reacting with

madreJ [45]

We calculate for the number of moles of water given its mass by dividing the given mass by the molar mass.
n water = (36.04 g) / (18 g/mol)
n water = 2 mols
From the given balanced equation, every 6 moles of water produced will require 7 moles of oxygen.
n oxygen = (2 mols H2O) x (7 moles O2 / 6 moles H2O)
n oxygen = 2.33 mols O2

3 0

3 years ago

Which of the following equations best describes the energy at point

rusak2 [61]

Answer:

The correct option is

B. PEA = KEC + PEC

Explanation:

The potential energy is the energy possessed due to position

From the image the point with the highest position and therefore the most potential energy and the lowest or zero kinetic energy is point A

Given that we have;

Total mechanical energy = The potential energy + The kinetic energy

Where there is constant total mechanical energy in the system, then, at the point A where the kinetic energy is zero, the potential energy is equal to the total mechanical of the system, we have;

Total mechanical energy = The potential energy at A = PEA

Total mechanical energy = PEA

At point C where we have the total mechanical energy presented as follows;

Total mechanical energy = Kinetic energy at C + Potential energy at C

Total mechanical energy = KEC + PEC

Therefore;

PEA = KEC + PEC.

7 0

3 years ago

How many grams of iron metal do you expect to be produced when 325 grams of an 87.5 percent by mass iron (II) nitrate solution r

Debora [2.8K]

Answer: 88.2 g

Solution:

1) Chemical equation:

<span>2Al (s) + 3Fe(NO3)2 (aq) → 3Fe (s) + 2Al(NO3)3 (aq)

2) Theoretical molar ratios

2 mol Al : 3 mol Fe(NO3)2 : 3 mol Fe : 2 mol Al(NO3)3

3) Starting mass of pure iron nitrate

% = (mass of iron nitrate / mass of solution) * 100 = 87.5

=> mass of iron nitrate = 87.5 * mass of solution / 100

mass of solution = 325 g

=> mass of iron nitrate = 87.5 * 325 g / 100 = 284.375 g

4) moles of iron nitrate

moles = mass in grams / molar mass

molar mass of Fe(NO3)2 = 179.85 g/mol

moles = 284.375 g/ 179.85 g/mol = 1.58 moles Fe(NO3)2

5) proportion:

             x                                 3 mol Fe
--------------------------- =     ----------------------
1.58 mol Fe(NO3)2          3 mol Fe(NO3)2

Clear x:

x = 1.58 mol Fe

6) Convert 1.58 mol Fe into grams

mass = number of moles * atomic mass

atomic mass of iron = 55.845 g / mol

mass = 1.58 moles * 55.845 g/mol = 88.24 g

Rounded to 3 significant figures: 88.2 grams of Fe.
</span>

6 0

3 years ago

neon has 3 different isotopes, neon-20, neon-21, and neon-22. the first isotope has a mass 19.992 amu and an abundance of 90.60%

il63 [147K]

Isotopes

Mass atom of Neon: 20.1797 amu

Mass atom X = mass isotope 1 . % + mass isotope 2.% +.....

$\tt 20.1797=19.992\times 0.906+x\times 0.0021+21.991.0\times 0920\\\\x=20.846~amu$

4 0

3 years ago

Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO 3 (s) PbO (s) CO 2 (g) ________ grams of lead (I

blsea [12.9K]

Answer:

We will have 7.30 grams lead(II) oxide

Explanation:

Step 1: Data given

Mass of lead (II)carbonate = 8.75 grams

Molar mass PbCO3 = 267.21 g/mol

Step 2: The balanced equation

PbCO3 (s) ⇆ PbO(s) + CO2(g)

Step 3: Calculate moles PbCO3

Moles PbCO3 = mass / molar mass

Moles PbCO3 = 8.75 grams / 267.21 g/mol

Moles PbCO3 = 0.0327 moles

Step 4: Calculate moles PbO

For 1 mol PbCO3 we'll have 1 mol PbO and 1 mol CO2

For 0.0327 moles PbCO3 we'll have 0.0327 moles PbO

Step 5: Calculate mass PbO

Mass PbO = moles PbO * molar mass PbO

Mass PbO = 0.0327 moles * 223.2 g/mol

Mass PbO = 7.30 grams

We will have 7.30 grams lead(II) oxide

7 0

4 years ago