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3 years ago

How is the law of conservation of mass shown by a balanced chemical equation?

Chemistry

1 answer:

valina [46]3 years ago

7 0

Answer:

Matter cannot be created or destroyed in chemical reactions. This is the law of conservation of mass. In every chemical reaction, the same mass of matter must end up in the products as started in the reactants. Balanced chemical equations show that mass is conserved in chemical reactions.

Hope this helps! (:

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What is the amount of energy (in kJ) released when 1 mole of photons are emitted from an electron transition of n

pychu [463]

Explanation:

The formula applied here is rydberg's equation (Bohr's equation.)

E = -Rh (1/(nf)^2 - 1/(ni)^2)

where Rh = Rydberg constant = 2.8*10^-18

1 mole = 6.02 * 10^23 particles

nf & ni stand for final & initial principal quantum numbers respectively.

your question lacks the principal quantum numbers.

3 0

2 years ago

2. A photon of wavelength for 4 x10 -7 m strikes on the metal surface the work

lina2011 [118]

Answer:

See explanation

Explanation:

Energy of the photon;

E = hc/λ

h= Planks constant

c= speed of light

λ = wavelength

E= 6.6 × 10^-34 × 3 × 10^8/4 x10 -7

E = 4.95 × 10^-19 J

If 1ev=1.602x10-19 J

x = 4.95 × 10^-19 J

x= 3.1 ev

From Einstein's photoelectric equation;

KE = E - Wo

Where;

KE = kinetic energy of ejected photoelectron

E= energy of the photon

Wo= work function of the metal

KE = 3.1 eV - 2.13 eV

KE= 0.97 eV

KE = 0.97 eV × 1.602x10-19 J

KE = 1.55 × 10^-19 J

KE = 1/2 mv^2

1.55 × 10^-19= 1/2 × 9.1 × 10^-31 × v^2

v= √2 × 1.55 × 10^-19/9.1 × 10^-31

v= 5.8 × 10^5 m/s

4 0

3 years ago

The table shows five items that a person may consider including in a safety contract.

zhenek [66]

Answer:

1,2, and 5

Explanation:

5 0

3 years ago

A sample of helium has a volume of 50.00 L at STP. How many helium atoms are in the sample? Show work

Setler79 [48]

Answer:

Explanation:

molar volume at STP=22.4 L

given volume=50.0 L

number of moles=given volume/molar volume

number of moles=50.0/22.4

number of moles=2.2

1 mole of helium =6.023*10^23 atoms

2.2 moles of helium =6.023*10^23*2.2=1.3*10^24

therefore 50.0 L of helium contain 1.33*10^24 atoms

4 0

3 years ago

CH4 + O2 → CO2 + H2O

Scilla [17]

Answer:

9.8 × 10²⁴ molecules H₂O

General Formulas and Concepts:

Atomic Structure

Reading a Periodic Table
Moles
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Organic

Naming carbons

Stoichiometry

Analyzing reaction rxn
Using Dimensional Analysis

Explanation:

Step 1: Define

[RxN - Unbalanced] CH₄ + O₂ → CO₂ + H₂O

[RxN - Balanced] CH₄ + 2O₂ → CO₂ + 2H₂O

[Given] 130 g CH₄

Step 2: Identify Conversions

Avogadro's Number

[RxN] 1 mol CH₄ → 2 mol H₂O

[PT] Molar Mass of C: 12.01 g/mol

[PT] Molar Mass of H: 1.01 g/mol

Molar Mass of CH₄: 12.01 + 4(1.01) = 16.05 g/mol

Step 3: Stoichiometry

[DA] Set up conversion: $\displaystyle 130 \ g \ CH_4(\frac{1 \ mol \ CH_4}{16.05 \ g \ CH_4})(\frac{2 \ mol \ H_2O}{1 \ mol \ CH_4})(\frac{6.022 \cdot 10^{23} \ molecules \ H_2O}{1 \ mol \ H_2O})$
[DA] Divide/Multiply [Cancel out units]: $\displaystyle 9.75526 \cdot 10^{24} \ molecules \ H_2O$

Step 4: Check

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

9.75526 × 10²⁴ molecules H₂O ≈ 9.8 × 10²⁴ molecules H₂O

8 0

2 years ago