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3 years ago

I NEED HELP ASAP DON'T JUST ANSWER FOR POINTS OR YOU WILL GET REPORTED!

Chemistry

2 answers:

White raven [17]3 years ago

7 0

Answer:

The number of neutrons is entirely dependent on the Mass number of the particular atom. The standard mass for potassium is 39.

Potassium is element number 19, so it has 19 protons and 19 electrons in the neutral atom. It has therefore 39-19 = 20 Neutrons.

Explanation:

Lelu [443]3 years ago

4 0

Answer:

Number of Protons 19

Explanation:

Number of Neutrons 20

Number of Electrons 19

Melting Point 63.65° C

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A mineral is scratched by apatite but not by calcite what could it’s hardness value be

mojhsa [17]

Answer:

hi!

Explanation:

The Mohs Hardness Scale ranks the order of hardness of minerals and some common objects. For example, your fingernail can scratch the minerals talc and gypsum, with a hardness of 2 or lower. A copper penny can scratch calcite, gypsum, and talc.

One of the most important tests for identifying mineral specimens is the Mohs Hardness Test.

This test compares the resistance of a mineral to being scratched by ten reference minerals known as the Mohs Hardness Scale (see table at left).

The test is useful because most specimens of a given mineral are very close to the same hardness. This makes hardness a reliable diagnostic property for most minerals.

"Hardness" is the resistance of a material to being scratched. The test is conducted by placing a sharp point of one specimen on an unmarked surface of another specimen and attempting to produce a scratch.

5 0

3 years ago

Read 2 more answers

A sample of gas is held at 100oc at a volume of 20 L.if the volume is increased to 40 L what is the new temperature of the gas i

ElenaW [278]

Answer:

470 °C

Explanation:

This looks like a case where we can use Charles’ Law:

$\dfrac{V_{1}}{T_{1}} =\dfrac{V_{2}}{T_{2}}$

Data:

V₁ = 20 L; T₁ = 100 °C

V₂ = 40 L; T₂ = ?

Calculations:

(a) Convert the temperature to kelvins

T₁ = (100 + 273.15) K = 373.15 K

(b) Calculate the new temperature

$\begin{array}{rcl}\dfrac{V_{1}}{T_{1}}& =&\dfrac{V_{2}}{T_{2}}\\\\ \dfrac{\text{20 L}}{\text{373.15 K}} &=&\dfrac{\text{40 L}}{T_{2}}\\\\{\text{15 000 K}} & = & 20T_{2}\\T_{2} & = &\dfrac{\text{15 000 K}}{20 }\\\\T_{2} & = & \textbf{750 K}\\\end{array}$

Note: The answer can have only two significant figures because that is all you gave for the volumes.

(c) Convert the temperature to Celsius

T₂ = (750 – 273.15) °C = 470 °C

3 0

3 years ago

What is the effect of tap water, sea water, and rainwater on the rusting rate of iron?

UkoKoshka [18]

Answer:

The more acidic the solution the faster it rusts. More Na = more rust

Explanation:

4 0

3 years ago

Are the following quantum number combinations allowed? If not, show two ways to correct them:

evablogger [386]

Answer:

(a) n = 2; l = 0; ml = -1 ⇒ WRONG

change ml = 0, or l = 1 to correct.

(b) n = 4, l = 3; ml = -1 ⇒ CORRECT

(d) n = 5, l = 2; ml = +3 ⇒ WRONG

change ml = 0, ±1 or ±2, or l = 3 or l = 4 to correct.

Explanation:

The rules for electron quantum numbers are:

1. Shell number, 1 ≤ n

2. Subshell number, 0 ≤ l ≤ n − 1

3. Orbital energy shift, -l ≤ ml ≤ l

4. Spin, either -1/2 or +1/2

Now, apply in our case

(a) n = 2; l = 0; ml = -1 ⇒ WRONG

-l ≤ ml ≤ l, so either change ml = 0 or l = 1 to correct.

(b) n = 4, l = 3; ml = -1 ⇒ CORRECT

(d) n = 5, l = 2; ml = +3 ⇒ WRONG

-l ≤ ml ≤ l, so either change ml = 0, ±1 or ±2, or l = 3 or l = 4 to correct.

7 0

4 years ago

What can a swarm of grasshoppers do to a farmers crop?

Brums [2.3K]

It could destroy the crops by jumping all over them

8 0

3 years ago