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3 years ago

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People have developed models of the universe for thousands of years. Identify two observations that a model of the universe woul

d need to explain in order to be useful

1 answer:

ella [17]3 years ago

4 0

It It would both need to show and explaine the universe

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Consider a buffer solution that is 0.50 M in NH3 and 0.20 M in NH4Cl. For ammonia, pKb=4.75. Calculate the pH of 1.0 L of the so

vladimir2022 [97]

You have 0.50 mol of NH3 and 0.20 mol of NH4+ to start (NH4Cl dissolves completely), given the molarity and 1.0 L solution.

30.0 mL of 1.0 M HCl is 0.0300 mol of HCl. This will react with the NH3 to produced 0.030 mol of NH4+.

You now have 0.47 mol NH3 and 0.23 mol NH4+. Now use the Henderson-Hasselbach equation to calculate your pH. The equation says to use concentration of acid and base, but you can just use the moles of them because it doesn’t make a difference.

pH = pKa + log(base/acid)

pKa = 14 - pKb = 14 - 4.75 = 9.25

pH = 9.25 + log(0.47/0.23) = 9.56

5 0

3 years ago

const2013 [10]

Answer:

b

Explanation:

6 0

3 years ago

An atom has a mass number of 24 and 13 neutrons. what is the atomic number of this atom? express your answer as an integer.

Murljashka [212]

A=24
N(n)=13

N(p)=A-N(n)

N(p)=24-13=11

²⁴Na - sodium

atomic number is 11

5 0

3 years ago

How do you find the number of neutrons in an element

e-lub [12.9K]

Answer:

Mass number -Atomic number

6 0

3 years ago

Read 2 more answers

What is the correct ratio of the atoms of the two elements present in a sample of the compound copper chloride, CuCl2?

Aleonysh [2.5K]

The correct ratio of the atoms of the two elements in the sample of copper chloride compound would be 1:2.

<h3>Atoms of elements</h3>

Copper chloride has a chemical formula, $CuCl_2$ .

Thus, an atom of copper, Cu, combines with 2 atoms of chlorine, Cl.

The 2 chlorine atoms are recipients of an electron each from the copper atom which happens to have 2 electrons in its outermost valence shell.

Therefore, the ratio of copper to chlorine atoms in the compound is 1:2.

More on atoms of elements can be found here: brainly.com/question/15173445

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8 0

2 years ago