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3 years ago

Which phrase best defines radiant energy? (a)mechanical waves that require a medium to travel through

Chemistry

2 answers:

aleksklad [387]3 years ago

4 0

Answer:

D.) Energy transmitted by an electromagnetic wave.

Explanation:

In physics, and in particular as measured by radiometry, radiant energy is the energy of electromagnetic and gravitational radiation.

slava [35]3 years ago

3 0

Answer:

I think is b

Explanation:

if im wrong, heres some information:

mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium.[1] While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefore, the oscillating material does not move far from its initial equilibrium position. Mechanical waves transport energy. This energy propagates in the same direction as the wave. Any kind of wave (mechanical or electromagnetic) has a certain energy. Mechanical waves can be produced only in media which possess elasticity and inertia.

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"A crosslinked copolymer consists of 57 wt% ethylene (C2H4) repeat units and 43 wt% propylene (C3H6) repeat units. Determine the

ch4aika [34]

Explanation:

Percentage ethylene by weight = 57%

Percentage propylene by weight = 43%

Suppose in 100 grams of polymer:

Mass of ethylene = 57 g

Mass of propylene = 43 g

Moles of ethylene = $\frac{57 g}{28 g/mol}=2.036 mol$

Moles of propylene = $\frac{43g}{42g/mol}=1.024 mol$

1 mole = $N_A =6.022\times 10^{23}$ molecules/ atoms

Units of ethylene = $2.036 mol\times N_A$

Units of propylene = $1.024 mol\times N_A$

a) Fraction of ethylene units:

$=\frac{2.036 mol\times N_A}{2.306 mol\times N_A+1.024 mol\times N_A}=\frac{509}{765}$

b ) Fraction of propylene units:

$=\frac{1.024mol\times N_A}{2.306 mol\times N_A+1.024 mol\times N_A}=\frac{256}{765}$

3 0

3 years ago

What particle decay is this? 210 83 Bi→210 84 Po

sesenic [268]

Answer:

Beta emission

Explanation:

In beta emission, a neutron is converted into a proton thereby emitting an electron and a neutrino. A neutrino is a particle that serves to balance the spins.

When a nucleus undergoes beta emission, the mass number of the parent and daughter nuclei remain the same while the atomic number of the daughter nucleus is greater than that of its parent by one unit.

Hence, in beta emission, the daughter nucleus is found one pace to the right of the parent in the periodic table.

3 0

3 years ago

Given the standard enthalpy changes for the following two reactions:

lawyer [7]

Answer:

ΔH° = -186.2 kJ

Explanation:

Hello,

This case in which the Hess method is applied to compute the required chemical reaction. Thus, we should arrange the given first two reactions as:

(1) it is changed as:

SnCl2(s) --> Sn(s) + Cl2(g)...... ΔH° = 325.1 kJ

That is why the enthalpy of reaction sign is inverted.

(2) remains the same:

Sn(s) + 2Cl2(g) --> SnCl4(l)......ΔH° = -511.3 kJ

Therefore, by adding them, we obtain the requested chemical reaction:

(3) SnCl2(s) + Cl2(g) --> SnCl4(l)

For which the enthalpy change is:

ΔH° = 325.1 kJ - 511.3 kJ

ΔH° = -186.2 kJ

Best regards.

7 0

3 years ago

Read 2 more answers

Plant cells have a large central vacuole, which animal cells lack. What function does this organelle perform?

Lapatulllka [165]

The central vacuole stores materials, wastes, and helps give the plant structure and support.

Hope this helps!

5 0

3 years ago

Read 2 more answers

A solution is made by combining 500 mL of 0.10 M HF (Ka=7.2 x 10^-4) with 300 mL of 0.15 M NaF. What is the pH of the resulting

n200080 [17]

Answer:

b) 3.10

Explanation:

HF ⇄ H + + F

Using Henderson-Hasselbalch Equation:

pH = pKa + log [A-]/[HA].

Where;

pKa = Dissociation constant = -log Ka

Hence, pKa of HF = -log 7.2 x 10^-4 = 3.14266

[A-] = concentration of conjugate base after dissociation = moles of base/total volume

= 0.15 x 0.3/0.8

= 0.05625 M

[HA] = concentration of the acid = moles of acid/total volume

= 0.10 x 0.5/0.8

= 0.0625 M

Note: Total volume = 500 + 300 = 800 mL = 0.8 dm3

pH = 3.14266 + log [0.05625/0.0625]

= 3.14267 + (-0.04575749056)

= 3.09691250944

From all the available options below:

a) 2.97

b) 3.10

c) 3.19

d) 3.22

e) 3.32

The correct option is b.

4 0

3 years ago