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3 years ago

One type of sunburn occurs when skin is exposed

Chemistry

1 answer:

julia-pushkina [17]3 years ago

8 0

Answer:

E = 6.27 × 10⁻²³ Joules

Explanation:

E = h (Plancks constant) × f (frequency)

(Plancks constant = 6.63 × 10⁻³⁴ J×s)

f = λ × c (used to find frequency so you can satisfy energy equation)

*Have to find wavelength in meters to multiply by speed of light*

1. f = (3.15 × 10⁻⁷ m) × (3 × 10⁸ m/s)

2. f = 9.45 × 10¹⁰ s

3. E = (6.63 × 10⁻³⁴ J×s [Plancks constant]) × (9.45 × 10¹⁰ s)

E = 6.27 × 10⁻²³ Joules

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Which elements do not have a set number of valence electrons?

laila [671]

Answer:

the answer would be B. hope this helps!

Explanation:

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3 years ago

Which of the following are building blocks of elements A. Atoms B. Protons C. Ions 2. Atoms are made up of A. Air,water,soil B.

Serjik [45]

1. A - atoms

2. B - protons electrons and neutrons

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3 years ago

What makes metalloids a group of their own?

mestny [16]

Answer:

The metalloids are in a group of elements in the periodic table we know for the kinds of atom types.

Explanation:

Hope this helps u.. :D

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3 years ago

Convert 35 joules into calories.<br> OR 1.410 cal<br> OC 82,500 cal<br> OD. 1.420,000 cal

lesya692 [45]

Answer:

0.83Cal

Explanation:

Given parameters:

Amount of energy given;

35J;

Convert to Cal;

1 calorie = 42 joules

x calories = 35 joules

Cross multiply;

42x = 35

x = $\frac{35}{42}$ = 0.83Cal

7 0

3 years ago

From the mass of Al reacted, how many moles are present? What is the mole ratio between Al and H2 in the balanced chemical react

tigry1 [53]

Answer:

From the mass of Al reacted, how many moles are present? We don't have the mass of Al reacted

What is the mole ratio between Al and H2 in the balanced chemical reaction?

By stoichiometry, ratio between Al and H₂ is 3:2

What units are required on the temperature when doing calculations with gases? °K degrees

The value of R is 0.082 L.atm/mol.K

Explanation:

A chemical reaction for this can be this one:

2Al (s) + 6HCl (aq) → 2AlCl₃(aq) + 3H₂ (g)

Balanced

To get the moles which are present in the mass of Al reacted you must calculate:

Al Mass / Al molar mass = Al moles

The Ideal Gas equation is this one:

Pressure . Volume = n° moles . R (gases constant) . T°K

The temperature must be in K, because the units of R

We usually use R = 0.082 L.atm/mol.K

5 0

3 years ago