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2 years ago

What happens to the total mass of a substance undergoing a physical change?

Chemistry

2 answers:

Mrrafil [7]2 years ago

8 0

Answer:

In a physical change, there is only a change in the form of the objects, but the chemical composition of the object remained the same. Since mass is affected by this composition, the mass of an object that undergone a physical change would remain the same.

Explanation:

Your welcome

fomenos2 years ago

6 0

It stays the same .

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in heating a kettle of water on an electric stove, 3.34×10^3 J of thermal energy was provided by the element of the stove. yet,

insens350 [35]

Answer:

The percentage efficiency of the electrical element is approximately 82.186%

Explanation:

The given parameters are;

The thermal energy provided by the stove element, $H_{supplied}$ = 3.34 × 10³ J

The amount thermal energy gained by the kettle, $H_{absorbed}$ = 5.95 × 10² J

The percentage efficiency of the electrical element in heating the kettle of water, η%, is given as follows;

$\eta \% = \dfrac{H_{supplied} - H_{absorbed} }{H_{supplied}} \times 100$

Therefore, we get;

$\eta \% = \dfrac{3.34 \times 10^3 - 5.95 \times 10^2}{3.34 \times 10^3} \times 100 = \dfrac{549}{668} \times 100 \approx 82.186 \%$

The percentage efficiency of the electrical element, η% ≈ 82.186%.

4 0

3 years ago

How many moles of CO gas are in 34.6 L?

Troyanec [42]

moles of CO gas : 1.545

<h3>Further explanation</h3>

Standard conditions for temperature and pressure are used as a reference in certain calculations or conditions

There are 2 conditions that are usually used as a reference : STP and RTP

Assuming the STP state :

Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters / mol.

Then for 34.6 L of CO gas :

$\tt moles=\dfrac{34.6}{22.4}=1.545$

6 0

2 years ago

Aqua regia, a mixture of HCl and HNO₃, has been used since alchemical times to dissolve many metals, including gold. Its orange

marissa [1.9K]

Aqua regia is an oxidative mixture that is highly corrosive and is composed of hydrochloric acid and nitric acid. The Ea (rev) for the reaction is 3 kJ.

<h3>What is activation energy?</h3>

The activation energy is the minimum required energy by the reactant to undergo changes to form the product. The activation energy of the reverse reaction is given by the difference in the production state and transition state.

It is given as,

Ea (rev) = Ea (fwd) − ΔHrxn

Given,

ΔH° = 83KJ

Ea (fwd) = 86 kJ/mol

Substituting the values above as:

Ea (rev) = 86 - 83

= 3 kJ

Therefore, the activation energy of the reverse reaction is 3 kJ.

Learn more about activation energy, here:

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4 0

1 year ago

Which of the following best compares the structure of carbohydrates and nucleic acids?

Serga [27]

I believe the best description comparing the structure of carbohydrates and nucleic acids would be A.

5 0

3 years ago

Read 2 more answers

If a flask maintained at 674 K contains 0.138 moles of NH4I(s) in equilibrium with 4.34×10-2 M NH3(g) and 9.39×10-2 M HI(g), wha

r-ruslan [8.4K]

Answer:

K = 4.07x10⁻³

Explanation:

Based on the reaction:

NH₄I(s) ⇄ NH₃(g) + HI(g)

You can define K of equilibrium as the ratio of concentrations of reactants and products, thus:

K = [NH₃] [HI] / [NH₄I]

But, as NH₄I is a solid, is not taken into account in the equilibrium, that means K expression is:

K = [NH₃] [HI]

As the concentrations in equilibrium of the gases is:

[NH₃] = 4.34x10⁻²M

[HI] = 9.39x10⁻²M

Equilibrium constant, K, is:

K = 4.34x10⁻²M * 9.39x10⁻²M

4 0

2 years ago