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3 years ago

How do balanced chemical equations show the conservation of mass

Chemistry

2 answers:

antiseptic1488 [7]3 years ago

4 0

Answer: Matter cannot be created or destroyed

Explanation: Balanced equations are set equations we cannot change one element or compound in the equation without changing the entire equation. So balanced equation show the conservation of mass because while other substances may be formed from the synthesis or decomposition of compounds new elements are never introduced and are not created out of thin air :)

Rudiy273 years ago

3 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.

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A certain first-order reaction (A→products) has a rate constant of 8.10×10−3 s−1 at 45 ∘C. How many minutes does it take for the

stira [4]

Answer:

The answer is 5.7 minutes

Explanation:

A first-order reaction follow the law of $Ln [A] = -k.t + Ln [A]_{0}$ . Where [A] is the concentration of the reactant at any t time of the reaction, $[A]_{0}$ is the concentration of the reactant at the beginning of the reaction and k is the rate constant.

Dropping the concentration of the reactant to 6.25% means the concentration of A at the end of the reaction has to be $[A]=\frac{6.25}{100}.[A]_{0}$ . And the rate constant (k) is 8.10×10−3 s−1

Replacing the equation of the law:

$Ln \frac{6.25}{100}.[A]_{0} = -8.10x10^{-3}s^{-1}.t + Ln[A]_{0}$

Clearing the equation:

$Ln [A]_{0}.\frac{6.25}{100} - Ln [A]_{0} = -8.10x10^{-3}s^{-1}.t$

Considering the property of logarithms: $Ln A - Ln B = Ln \frac{A}{B}$

Using the property:

$Ln \frac{[A]_{0}}{[A]_{0}}.\frac{6.25}{100} = -8.10x10^{-3}s^{-1}.t$

Clearing t and solving:

$t = \frac{Ln \frac{6.25}{100} }{-8.10x10^{-3}s^{-1} } = 342.3s$

The answer is in the unit of seconds, but every minute contains 60 seconds, converting the units:

$342.3x\frac{1min}{60s} = 5.7min$

6 0

3 years ago

The first ionization energy, e, of a potassium atom is 0.696 aj. what is the wavelength of light, in nm, that is just sufficient

elena55 [62]

The formula to be used for this problem is as follows:

E = hc/λ, where h is the Planck's constant, c is the speed of light and λ is the wavelength. Also 1 aJ = 10⁻¹⁸ J

0.696×10⁻¹⁸ = (6.62607004×10⁻³⁴ m²·kg/s)(3×10⁸ m/s)/λ
Solving for λ,
λ = 2.656×10⁻⁷ m or 0.022656 nm

6 0

3 years ago

What neutral element has 17 electrons an 18 neutrons?

pishuonlain [190]

Answer:

chlorine atom

A chlorine atom has 17 protons, 18 neutrons, and 17 electrons.

Explanation:

4 0

2 years ago

Read 2 more answers

If 42.8 mL of 0.204 M HCl solution is needed to neutralize a solution of Ca(OH)2, how many grams of Ca(OH)2 must be in the solut

Aneli [31]

Hey There!

At neutralisation moles of H⁺ from HCl = moles of OH⁻ from Ca(OH)2 so :

0.204 * 42.8 / 1000 => 0.0087312 moles

Moles of Ca(OH)2 :

2 HCl + Ca(OH)2 = CaCl2 + 2 H2O

0.0087312 / 2 => 0.0043656 moles ( since each Ca(OH)2 ives 2 OH⁻ ions )

Therefore:

Molar mass Ca(OH)2 = 74.1 g/mol

mass = moles of Ca(OH)2 * molar mass

mass = 0.0043656 * 74.1

mass = 0.32 g of Ca(OH)2

Hope that helps!

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3 years ago

How many significant figures are in the quantity 12.0 mL? O A. 1 B. 2 C. 3 O D. 12

insens350 [35]

Answer:

C. 3

Explanation:

12.0 - 3 significant figures 1,2 and 0, because 0 is after decimal point.

7 0

3 years ago