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3 years ago

Which statement about atoms and molecules is

Chemistry

2 answers:

Pavel [41]3 years ago

8 0

Elements always exist as pair of atoms called molecules .

Explanation:-

The material which has only one types of similar atoms called element .
Ex:-Sodium,Carbon etc

zhuklara [117]3 years ago

3 0

Answer:

Elements always exists as pairs of atoms called molecules

Explanation:

Elements are simply substances in its pure form.
The atom of an element is simply referring to a single element. eg we have sodium atom as Na, it appears singly and in its pure form
A molecule then refers to when an atom of the same element is paired up. i.e not in a single state. eg, we have one atom of hydrogen molecule as H2, Oxygen molecule as O2.
Note. the molecular elements appear in pairs while the atomic elements appear singly.

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a. Calculate the pH of a solution that has [H3O+]= 4.3 x 10-5 M. b. Is the solution acidic or basic? How do you know?

Luda [366]

Answer:

* $pH=4.37$

* The solution is acidic since the pH is below 7.

Explanation:

Hello,

In this case, we can mathematically define the pH by:

$pH=-log([H_3O^+])$

Thus, for the given hydronium concentration we simply compute the pH:

$pH=-log(4.3x10^{-5})=4.37$

Thereby, we conclude the solution is acidic due to the fact that the pH is below 7 which is the neutral point and above it the solutions are basic.

Regards.

3 0

3 years ago

If a reaction occurs, what will be the products of the unbalanced reaction below?

castortr0y [4]

Explanation:

I think the correct answer is B

Hope this helped u

8 0

3 years ago

At standard temperature and pressure. 0.500 mole of xenon gas occupies

ANEK [815]

Answer:

0.500 mole of Xe (g) occupies 11.2 L at STP.

General Formulas and Concepts:

Gas Laws

STP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm, 273 K

Stoichiometry

Mole ratio
Dimensional Analysis

Explanation:

Step 1: Define

Identify.

0.500 mole Xe (g)

Step 2: Convert

[DA] Set up: $\displaystyle 0.500 \ \text{mole Xe} \bigg( \frac{22.4 \ \text{L Xe}}{1 \ \text{mole Xe}} \bigg)$
[DA] Evaluate: $\displaystyle 0.500 \ \text{mole Xe} \bigg( \frac{22.4 \ \text{L Xe}}{1 \ \text{mole Xe}} \bigg) = 11.2 \ \text{L Xe}$

Topic: AP Chemistry

Unit: Stoichiometry

3 0

2 years ago

The half-life of radium-226 is 1590 years. if a sample contains 100 mg, how many mg will remain after 1000 years?

Katyanochek1 [597]

Answer:

$a=64.7mg$

Explanation:

Hello,

In this case, we need to remember that for the required time for a radioactive nuclide as radium-226 to decrease to one half its initial amount we are talking about its half-life. Furthermore, the amount of remaining radioactive material as a function of the half-lives is computed as follows:

$a=a_0(\frac{1}{2} )^{\frac{t}{t_{1/2}} }$

Therefore, for an initial amount of 100 mg with a half-life of 1590 years, after 1000 years, we have:

$a=100mg(\frac{1}{2} )^{\frac{1000years}{1590years} }\\\\a=64.7mg$

Best regards.

4 0

3 years ago

Consider this reaction:

ryzh [129]

Answer:

I think it's 6 moles are produced

3 0

2 years ago