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3 years ago

What is the most metallic element in group 14?

1 answer:

7 0

The most metallic element in group 14 is francium. However, it is a <span>man-made element, except for one isotope, and all isotopes are so radioactive they almost instantly decay into another element.</span>

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How are energy and mass connected during the formation of an atom?

Jlenok [28]

I think the right answer for this question is option A. The energy absorbed so the mass will be increased.

6 0

3 years ago

What will most likely happen if a sound wave moves from the air through a solid?

Alchen [17]

<span>The wavelength of the associated sound will increase. This will be noticed by the sound having a lower tone. As the sound passes through the solid object, not only will it sound lower in tone, it will sound softer, evidenced by if a person closes a door to a room and listens to a sound played from inside.</span>

7 0

3 years ago

Read 2 more answers

What is the pH at the half-equivalence point in the titration of a weak base with a strong acid? The pKb of the weak base is 7.9

ValentinkaMS [17]

Hey there!

Given the reaction:

B + H⁺ => HB⁺

At half-equivalence point : [B] = [HB⁺]

=> [B] / [HB⁺] = 1

Henderson-Hasselbalch equation :

pH = pKa + log ( [B] ) / ( HB⁺)]

pH = 14 - pKb + log ( 1 )

pH = 14 - 7.95 + 0

pH = 6.05

Answer C

Hope that helps!

5 0

3 years ago

Properties of a substance which can be measured or observed without altering the identity of the substance being measured are __

rosijanka [135]

Answer:

The correct answer is physical properties and/or phase properties.

Explanation:

Chemical properties can alter the substance (if you burn wood, it becomes ash and is no longer wood).

Reactive properties are also chemically changing the substance.

Phase properties are where the element can be in solid, liquid, or gas form so these could also be an answer.

8 0

3 years ago

A crime lab received a 235-gram sample. The sample had a molecular mass of 128.1 grams and the empirical formula is CH2O. How ma

kvv77 [185]

Explanation:

Given parameters:

Mass of sample = 235g

Molecular mass of sample = 128.1g

Empirical formula = CH₂O

Unknown:

Mass of each element in the sample = ?

Solution:

To solve this problem, we must know that the empirical formula of any compound is the simplest ratio of the atoms it contains. This is not the true formula of the compound.

Molecular formula = (Empirical formula)ₙ

Let us find the molecular mass of the sample;

CH₂O = 12 + 2(1) + 16 = 30g

128.1 = (30)n

n = 4

The molecular formula of the compound is; (CH₂O)₄ = C₄H₈O₄

Now to find the grams of each element in the sample;

Express the molecular mass of each element and that of the compound as a fraction and multiply with the given mass;

For C;

$\frac{4 x 12}{128.1} x 235\\$ = 88.06g