2 years ago

True or false? dry ice subliming (turning from a solid straight into a gas) is an example of a chemical change.

1 answer:

5 0

False because when a substance changes from one state of matter to another it is a physical change no matter how many states of matter it skips

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Explain why liquids and gases differ in density and ability to be compressed ?

EastWind [94]

Gases are less dense and the molecules are farther apart which means that it can be compressed

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2 years ago

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An ion always has a ________ or ________ charge. While a covalent bond always has no _________, meaning it is __________.

almond37 [142]

An ion has a positive or negative charge. While a covalent bond always has no charge, meaning it is neutral.

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3 years ago

The decomposition of dinitrogen pentoxide, N2O5, to NO2 and O2 is a first-order reaction. At 60°C, the rate constant is 2.8 × 10

Sati [7]

Answer:

a. 113 min

Explanation:

Considering the equilibrium:-

2N₂O₅ ⇔ 4NO₂ + O₂

At t = 0 125 kPa

At t = teq 125 - 2x 4x x

Thus, total pressure = 125 - 2x + 4x + x = 125 - 3x

125 - 3x = 176 kPa

x = 17 kPa

Remaining pressure of N₂O₅ = 125 - 2*17 kPa = 91 kPa

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

Given that:

The rate constant, k = $2.8\times 10^{-3}$ min⁻¹

Initial concentration $[A_0]$ = 125 kPa

Final concentration $[A_t]$ = 91 kPa

Time = ?

Applying in the above equation, we get that:-

$91=125e^{-2.8\times 10^{-3}\times t}$

$125e^{-2.8\times \:10^{-3}t}=91$

$-2.8\times \:10^{-3}t=\ln \left(\frac{91}{125}\right)$

$t=113\ min$

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2 years ago

If an element has 3 valence electrons, what charge will likely form on its ion? Hint: It will lose those electrons. What happens

guajiro [1.7K]

Answer:

The answer to your question is: letter A

Explanation:

If an atom lose 3 electrons its charge will be positive, it will be +3

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2 years ago

How many protons are in an isotope of sodium with a mass number of 25?

Hunter-Best [27]

How many protons are in an isotope of sodium with a mass number of 25? 11

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2 years ago