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3 years ago

What types of organisms are most likely to become extinct (characteristics)?

1 answer:

4 0

Many rare and/or endemic species exhibit one or more of the following attributes which make them especially prone to extinction: (1) narrow (and single) geographical range, (2) only one or a few populations, (3) small population size and little genetic variability, (4) over-exploitation by people

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A sample of beach sand contains sand particles of different colors, small pebbles, and also shells. each component contains diff

JulijaS [17]

Answer is: this sample of sand is heterogeneous mixture.
Heterogeneous mixture is not uniform in composition (in this mixture different metals and minerals), but proportions of its components (in this mixture particles of different colors, small pebbles) vary throughout the sample.

5 0

3 years ago

Certain atoms emit photons of light with an energy of 3.820 ✕ 10−19 J. Calculate the frequency (in Hz) and wavelength (in nm) of

charle [14.2K]

Answer:

ν = 5,765x10¹⁴ Hz

λ = 520 nm

230,0 kJ/mole

Explanation:

To convert energy yo frequency you need to use:

E = hν

Where E is energy (3,820x10⁻¹⁹ J)

h is Planck's constant (6,626x10⁻³⁴ Js)

And ν is frequency, replacing ν = 5,765x10¹⁴ s⁻¹ ≡ 5,765x10¹⁴ Hz

To convert frequency to wavelength:

c = λν

Where s is speed of light (2,998x10⁸ ms⁻¹)

ν is frequency (5,765x10¹⁴ s⁻¹)

And λ is wavelength, replacing: λ = 5,200x10⁻⁷ ≡ 520 nm

If 1 photon produce 3,820x10⁻¹⁹ J, in mole of photons produce:

3,820x10⁻¹⁹ J × $\frac{6,022x10^{23}}{1 mole}$ = 230040 J/mole ≡ 230,0 kJ/mole

I hope it helps!

4 0

3 years ago

What is the percent-by-mass concentration of acetic acid (CH3COOH) in a vinegar solution that contains 51.80 g acetic acid in a

Semenov [28]

Answer : The percent-by-mass concentration of acetic acid is, 5.15 %

Explanation : Given,

Mass of acetic acid = 51.80 g

Density of solution = 1.005 g/ml

Volume of solution = 1.000 L = 1000 ml (1 L = 1000 ml)

First we have to calculate the mass of solution.

$\text{Mass of solution}=\text{Density of solution}\times \text{Volume of solution}$

$\text{Mass of solution}=1.005g/ml\times 1000ml=1005g$

Now we have to calculate the percent-by-mass concentration of acetic acid.

$\% \text{ by mass of acetic acid}=\frac{\text{Mass of acetic acid}}{\text{Mass of solution}}\times 100$

Now put all the given values in this formula, we get:

$\% \text{ by mass of acetic acid}=\frac{51.80g}{1005g}\times 100=5.15\%$

Therefore, the percent-by-mass concentration of acetic acid is, 5.15 %

6 0

2 years ago

? Question

masya89 [10]

Answer:

Gravity drives all mass wasting.

Explanation:

Mass wasting can be defined as the process of wasting away of earth's outer crust. This movement is also known as slope movement that causes large rock, soil, and debris to move downward, a force driven by gravity.

The term is often used interchangeably with landslide yet it is different. It is also known as mass movement as is cause massive downslope movement of rock, regolith, snow, ice, and-the-like on the earth's outer crust.

<u>All these movements are driven mainly by gravity. Gravity consantly tries to pull the rocks and soil down the slope but the resisting power. also known as shear strength, of moutains helps them to deny the gravitional force.</u>

Thus from the given options the statement that can be said to be true about mass wasting is that mass wasting is driven by gravity. So, the correct option is C.

4 0

3 years ago

How many electrons in an atom can have each of the following quantum number or sublevel designations?

Karo-lina-s [1.5K]

Answer: (a) 2 (b) 6 (c) 14

Explanation:

In the Azimuthal quantum number(l) electrons in a particular subshell (such as s, p, d, or f) are defined by values of l (0, 1, 2, or 3).

s is l=0, p is l=1, d is l=2, f is l=3.

The magnetic quantum number (ml) The value of ml can range from -l to +l, including zero. Thus the s, p, d, and f subshells contain 1, 3, 5, and 7 orbitals each, with values of m within the ranges 0, ±1, ±2, ±3 respectively. Each shell can have 2 x l + 1 sublevels, and each of these sublevel can accommodate up to two electrons.

(a) n=2, l=1, ml=0. If l=1 then 2 x 1+ 1=3 sublevels, 3*2=6 electrons. When l=1, ml =-1,0,+1, ml=0 accommodate two(2)electrons

(b) 5p. p is l=1 If l=1 then 2 x 1+ 1=3 sublevels, 3*2= electrons. This means in the 5 shell, the p orbital has 3 subshell and accommodate 6 electrons.

(c) n = 4, l = 3 if l=3 then 2 x 3+ 1=7 sublevel 7*2=14 electrons. This means the in the 4 shell, the f orbital has 7 subshell and accomdate 14 elections.

7 0

2 years ago