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2 years ago

Need help on stoichiometry asap please

Chemistry

1 answer:

lbvjy [14]2 years ago

8 0

1. Convert 135g Fe2O3 to moles, divide by 2, and multiply the resulting number by the molar mass of Al

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An element's atomic number is 68. How many protons would an atom of this element have?

Evgen [1.6K]

Answer: 68.

Explanation:

The atomic number is the number that idenfities an element.

The atomic number is the number of protons of an element.

Every element has a different number of protons.

The elements are arranged in the periodic table as per their atomic number (number of protons).

The first element is hydrogen (H), its atomic number is 1, and it has 1 proton.

The second element is helium (He), its atomic number is 2 (it has 2 protons)-

Those two elements form the first period (row) of the periodic table.

The second row (period) has the elements Li, Be, B, C, N, O, F and Ne, whose respective atomic numbers (number of protons are) 3, 4, 5, 6, 7, 8, 9, and 10, respectively.

And so, you may idenfity each of the 118 elements known, with a different atomic number (number of protons).

4 0

2 years ago

Read 2 more answers

Which of the following represents the electron configuration of rhodium

nordsb [41]

Answer:

i need a picture to solve

Explanation:

3 0

3 years ago

Convert 6.7 x 1024 molecules of nitrogen dioxide into grams.

BlackZzzverrR [31]

Answer:

510 g NO₂

General Formulas and Concepts:

Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
Reading the Periodic Table
Writing Compounds
Using Dimensional Analysis

Explanation:

Step 1: Define

6.7 × 10²⁴ molecules NO₂ (Nitrogen dioxide)

Step 2: Define conversions

Avogadro's Number

Molar Mass of N - 14.01 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of NO₂ - 14.01 + 2(16.00) = 46.01 g/mol

Step 3: Use Dimensional Analysis

$6.7 \cdot 10^{24} \ molecules \ NO_2(\frac{1 \ mol \ NO_2}{6.022 \cdot 10^{23} \ molecules \ NO_2} )(\frac{46.01 \ g \ NO_2}{1 \ mol \ NO_2} )$ = 511.901 g NO₂

Step 4: Check

We are given 2 sig figs. Follow sig fig rules.

511.901 g NO₂ ≈ 510 g NO₂

6 0

2 years ago

Calculate the total energy, in kilojoules, that is needed to turn a 46 g block

neonofarm [45]

Answer: The total energy, in kilojoules, that is needed to turn a 46 g block of ice at -25 degrees C into water vapor at 100 degrees C is 11.787 kJ.

Explanation:

Given: Mass = 46 g

Initial temperature = $-25^{o}C$

Final temperature = $100^{o}C$

Specific heat capacity of ice = 2.05 $J/g^{o}C$

Formula used to calculate the energy is as follows.

$q = m \times C \times (T_{2} - T_{1})$

where,

q = heat energy

m = mass

C = specific heat capacity

$T_{1}$ = initial temperature

$T_{2}$ = final temperature

Substitute the values into above formula as follows.

$q = m \times C \times (T_{2} - T_{1})\\= 46 g \times 2.05 J/g^{o}C \times (100 - (-25))^{o}C\\= 11787.5 J (1 J = 0.001 kJ)\\= 11.787 kJ$

Thus, we can conclude that the total energy, in kilojoules, that is needed to turn a 46 g block of ice at -25 degrees C into water vapor at 100 degrees C is 11.787 kJ.

7 0

2 years ago

How many moles of argon, Ar, are in 1.31×1024 Ar atoms?

ddd [48]

Answer:

2.18 mol Ar.

Explanation:

Hello there!

In this case, according to the definition of mole as the amount of particles of a given substance, it is possible to introduce the Avogadro's number to assert that 1 mole of any element contains 6.022x10²³ atoms; thus, the moles of Ar in the given amount of atoms turns out to be:

$1.31x10^{24}Ar atoms*\frac{1molAr}{6.022x10^{23}atoms}\\\\=2.18molAr$

Best regards!

5 0

2 years ago