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3 years ago

How does physical properties differ from chemical properties?

1 answer:

4 0

It's A.
Chemical properties cannot be determined by viewing or touching substance, and physical properties can be measured without changing the composition of matter:)

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Why is my family dissapointed in me?

Tems11 [23]

Answer:

literally same im failing almost every class and i just know my dad hates me because of it

Explanation:

6 0

3 years ago

Read 2 more answers

Technetium-99 is an ideal radioisotope for scanning organs because it has a half-life of 6.0 h and is a pure gamma emitter. supp

Nadusha1986 [10]

Answer: 20 mg Te-99 remains after 12 hours.

Explanation: N(t) = N(0)*(1/2)^(t/t1/2)

N(t) = (80 mg)*(0.5)^(12/6)

N(t) = 20 mg remains after 12 hours

3 0

2 years ago

Classify the following alcohol as primary,

Nata [24]

The classification of the alcohols gives;

Compound 1 - Primary alcohol
Compound 2 - Tertiary alcohol
Compound 3 - Secondary alcohol
Compound 4 - Secondary alcohol

<h3>What are alcohols?</h3>

Organic compounds occurs in families. The family of compounds is called a homologous series. The homologous series always have a functional group. The functional group is the atom, group of atoms or bond that is responsible for the chemical reactivity of the members of a given homologous series.

Now we know that the alcohols are those organic compounds that contains the -OH group. The could be aliphatic or alicyclic compounds. We shall now proceed to name the kind of alcohols that each of the compounds shown are;

Compound 1 - Primary alcohol
Compound 2 - Tertiary alcohol
Compound 3 - Secondary alcohol
Compound 4 - Secondary alcohol

Learn ore about alcohols:brainly.com/question/4698220

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3 0

2 years ago

Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natur

worty [1.4K]

Answer:

-376 kJ.

Explanation:

4 0

3 years ago

A rock contains 0.623 mg of 206Pb for every 1.000 mg of 238U present. Assuming that no lead was originally present, that all the

maxonik [38]

Answer:

t = 3,496x10⁹ years

Explanation:

The decay of ²³⁸U is:

²³⁸U → ²⁰⁶Pb + 8He + 6e⁻

Moles of ²⁰⁶Pb presents in 0,623mg are:

0,623x10⁻³g×(1mol / 206g) = 3,02x10⁻⁶ moles of ²⁰⁶Pb.

These moles are equals to moles of ²³⁸U before decay, that means, 3,02x10⁻⁶ moles²³⁸U

In grams:

3,02x10⁻⁶ moles²³⁸U× (238g / 1mol) = 7,20x10⁻⁴ g ²³⁸U = 0,720 mg²³⁸U

That means initial ²³⁸U was 1,000mg + 0,720mg =<em> 1,720mg</em>

Applying the formula:

ln (N₀/N) t₁₂ = t ln2

Where N₀ is initial amount of uranium (1,720mg), N is concentration of uranium (1,000mg), half-life time is a constant (t₁₂= 4,468x10⁹ years) and t is the time transcurred for the reaction. Replacing:

ln(1,720/1)*4,468x10⁹ years = t ln2

<em>t = 3,496x10⁹ years</em>

I hope it helps!

6 0

3 years ago