Lichens, a combination of fungi and algae, grow on the surface of rocks. They secrete acids that slowly eat away at the surface of the rock.

Is this an example of chemical or physical weathering?


physical


chemical

Answer:

1. False. White blood cells do.

2. False. Every seven years your cells are in the process of dying and being replaced. Although some cells don't die but your cells don't last for more than a period of 7 years.

3. True.

4. True.

5. False.

Explanation:

Answer:

[tex]\boxed {\boxed {\sf D. \ Sodium}}[/tex]

Explanation:

Valence electrons are electrons in the outermost shell.

One way to find valence electrons is with the electron configuration. This is often found on the Periodic Table. The last number in this configuration is the number of valence electrons, because an electron configuration shows where  electrons are located and the last number represents the outer shell.

In addition, all group 1 or alkali metals have 1 valence electrons. These include lithium, sodium, potassium, rubidium, cesium, and francium.

Even though we already know it is sodium based on valence electrons, here is an explanation of the reaction ratio.

Since sodium has 1 valence electron, it wants to get rid of it to satisfy the Octet Rule (8 valence electrons). Group 17 elements have 7 valence electrons, so they need 1. The two elements will react in a 1 to 1 ratio because the sodium donates its 1 excess electron to the group 17 element that needs 1.

The element that has 1 valence electron in its outer shell and will react with a group 17 element in a 1:1 ratio is sodium. Therefore, the correct option is option D.

The electrons in an atom's highest energy level, commonly referred to as the valence shell, are called valence electrons. These electrons interact with other atoms and participate in chemical bonds. Alkali metal sodium (Na), which belongs to group 1 of the periodic table, contains one valence electron in its outermost shell. Halogens, or group 17 elements, have 7 valence electrons.

Chlorine (Cl) is a member of group 17 and combines with sodium to generate sodium chloride (NaCl), an ionic compound. One sodium atom contributes its one valence electron to a chlorine atom, creating a stable ionic connection.

Therefore, the correct option is option D.

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Answer:

2.41 Litres

Explanation:

Using the combined gas law equation as follows;

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure (atm)

P2 = final pressure (atm)

V1 = initial volume (L)

V2 = final volume (L)

T1 = initial temperature (K)

T2 = final temperature (K)

According to the information provided in this question;

P1 = 1 atm

P2 = 0.65 atm

V1 = 1.75 liters

V2 = ?

T1 = 21°C = 21 + 273 = 294 K

T2 = -10°C = -10 + 273 = 263 K

Using P1V1/T1 = P2V2/T2

1 × 1.75/294 = 0.65 × V2/263

1.75/294 = 0.65V2/263

Cross multiply

294 × 0.65V2 = 1.75 × 263

191.1 V2 = 460.25

V2 = 460.25 ÷ 191.1

V2 = 2.41 L

Answer:

ok I want

have a good day better than yesterday

thanks a lot for your points

me too ahahahahahahahaha

Answer:

V1P1=V2P2

300*30=x*40

900=40x

decide both side by 40to be left by volume x

900÷40=x

x=225L

Answer:

0.897 J/g.⁰C

Explanation:

Given the following data:

m = 170 g (mass)

ΔT = 20.0⁰C (change in temperature)

q = 3050 J (amount of heat)

The amount of heat (q) is calculated as follows:

q = m x Cp x ΔT

Thus, we introduce the data in the mathematical expression to calculate the specific heat (Cp):

Cp = q/(m x ΔT) = 3050 J/(170 g x 20.0⁰C) = 0.897 J/g.⁰C

Answer:

5ppm

Explanation:

there are 1 million (1,000,000) µg (micrograms or mcg) per g (gram) ("micro" means millionth). So, 4. 1 part per million (ppm) for a 1g sample is 1 µg or .

I know you said no links, but this is a converter that explained it much better than I know how to

http://www.endmemo.com/sconvert/ppmug_g.php#:~:text=%C2%BB%20Microgram%2Fgram%20Conversions%3A&text=ug%2Fg%E2%86%94ppm%201%20ug%2Fg%20%3D%201%20ppm

heres a screenshot of the site (since i understand links are awful)

Answer:

The number of electrons in the outermost shell of an atom determines its reactivity. Noble gases have low reactivity because they have full electron shells. Halogens are highly reactive because they readily gain an electron to fill their outermost shell.

Hope this Helps!~

Answer:

b. [tex]\% diss =4.4x10^{-2}\%[/tex]

Explanation:

Hello there!

In this case, given the ionization reaction of HClO as weak acid:

[tex]HClO\rightleftharpoons H^++ClO^-[/tex]

We can write the equilibrium expression as shown below:

[tex]Ka=3.5x10^{-8}=\frac{[H^+][ClO^-]}{[HClO]}[/tex]

In such a way, via the definition of x as the reaction extent, we can write:

[tex]3.5x10^{-8}=\frac{x^2}{[HClO]}[/tex]

As long as Ka<<<<1 so that the x on the bottom can be neglected. Thus, we solve for x as shown below:

[tex]x=\sqrt{3.5x10^{-8}*0.18} =\\\\x=7.94x10^{-5}M[/tex]

And finally the percent dissociation:

[tex]\% diss=\frac{x}{[HClO]} *100\%\\\\\% diss=\frac{7.94x10^{-5}M}{0.18}*100\% \\\\\% diss =0.044\%=4.4x10^{-2}\%[/tex]

Which is choice b.

Best regards!

Answer: B

your welcome Bsbssnsnsmsllqql

Answer:

Alpha particle- B. He (Helium 4 atom )

He  represents an alpha particle and the correct option is option B.

Alpha particles are alternatively known as Alpha radiation or Alpha rays. It is a positively charged particle emitted from the decay of various radioactive materials.

They are emitted from the nucleus of some radionuclides during a form of radioactive decay, called alpha-decay.

Alpha particle mass is due to the two protons and two neutrons bonding.

An alpha-particle is identical to the nucleus of a normal (atomic mass four) helium atom i.e. a doubly ionised helium atom.

Therefore, He  represents an alpha particle and the correct option is option B.

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Answer:

the first on is Chromium(VI) peroxide or chromium oxide peroxide

the second on it Hydrogen Carbonate

Explanation:

I hope this helped ;)

Answer:

you probably not Finn look at this from 1 week

Explanation:

sooo ug

Explanation:

If you know the frequency of the photon, you can calculate the wavelength using the equation λ=cν where c is the speed of light and ν is the frequency.

λ=cν

f=T^-1,f=1/7.81×1014s

c=3×10^8m/s

λ=3×10^8m/s×1/7.81.×1014s

λ=37881.94m

Answer:

3

Explanation:

Answer:

3. 0.50 mol

Explanation:

Answer:

topaz and corundum

Explanation:

i know things

Answer:

Explanation:

False. The greater the concentration, the lower the freezing point.

Answer:

2 volts

Explanation:

I got that answer through a long process

Explanation:

                 Algae is a group of a photosynthetic eukaryotic organisms that plays a very important role on the ecosystem. It forms the lower base of the food chain and supports all the life forms of the ecosystem. It takes up water and carbon dioxide from the atmosphere to prepare food during the process of photosynthesis and maintains a balance in the ecosystem.

                In the context, if the algae disappears, the fish might die as the small fishes feeds on this algae. This is a concern as the algae is main component of food source and forms the base of the food chain. If there will be no algae there will be no life form on earth, as all species depend on each other to survive.

                  In order to prevent this from occurring, we must protect our algae. We must plant more trees, keep our water bodies healthy, we should not litter our ponds and lakes. We should also help these algae to grow and survive so that other life forms can feed them and thus maintain the ecosystem.

5.6 atm is  the partial pressure of the rest of the gases in the container other than the oxygen.

Each gas in a mixture adds to the overall pressure of a mixture. This portion represents the pressure. The pressure a gas would have if it were in its own volume and at its own temperature is known as the partial pressure. According to Dalton's law, the pressure distribution of an ideal gas mixture is equal to the combined partial pressures of the component gases.

The study of partial pressure is significant in the domains of physics, chemistry, and biology. The partial pressure of oxygen or carbon dioxide in the blood is used to calculate blood levels of each substance. The overall pressure in a container is equal to the sum of the partial pressures. The remaining gases must make up the remaining 5.6 atm if the oxygen partial pressure equals 4.2 atm and the sun reaches 9.8 atm in pressure.

Therefore, 5.6 atm is  the partial pressure of the rest of the gases in the container other than the oxygen.

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Answer: When the concentration of HI is tripled then the rate increases by a factor of 9.

Explanation:

The rate of a chemical reaction is the measure of concentration of reactants or the measure of concentration of products with respect to time.

As the rate of decomposition of HI is given as follows.

[tex]Rate = k[HI]^{2}[/tex]

When concentration of HI is tripled then the new rate will be as follows.

[tex]R^{'} = k[HI]^{2}\\= k \times (3)^{2}\\= 9k[/tex]

This shows that rate increases by a factor of 9.

Thus, we can conclude that when the concentration of HI is tripled then the rate increases by a factor of 9.

Answer:

B, C

Explanation:

Hope it helps i read it all

Answer:

85 g

Explanation:

molar mass of NH3 = 17 (get individual atom mass from periodic table and add)

to convert moles to grams use dimensional analysis

(5 mol) x (17 g / 1 mol)           basically just do 5 x 17

= 85 :)

Answer:

Filled below

Explanation:

#v.e means number of valence electrons.

Also, the column total v.e is gotten by adding the v.e of the metal to the v.e of the non metal based on the chemical formula of both of the 2 elements combined.

K: Cl: 5; KCl; 1 + 5 = 6

Be: S: 6; BeS; 2 + 6 = 8

Na: F: 7; NaF; 1 + 7 = 8

Mg: Se: MgSe; 2 + 6 = 8

Al; N; AlN; 1 + 5 = 6

Be; F; BeF2; 2 + 2(7) = 16

Mg; N; Mg3N2; 3(2) + 2(7) = 20

0001 M HCl is the same as saying that 1 *10-4 moles of H+ ions have been added to solution. The -log[. 0001] =4, so the pH of the solution =4.

Answer:

λ = 2.94 m (in meters)

λ = 2.94 x 10⁹ nm (in nanometers)

λ = 2.94 x 10¹⁰ A (in angstrom)

Explanation:

The wavelength of the radio station can be given as follows:

[tex]\lambda = \frac{c}{f}\\[/tex]

where,

λ = wavelength = ?

f = frequency = 102 MHz = 1.02 x 10⁸ Hz

c = speed of light = 3 x 10⁸ m/s

Therefore,

[tex]\lambda = \frac{3\ x\ 10^8\ m/s}{1.02\ x\ 10^8\ Hz}[/tex]

λ = 2.94 m (in meters)

λ = (2.94 m)(10⁹nm / 1 m)

λ = 2.94 x 10⁹ nm (in nanometers)

λ = (2.94 m)(10¹⁰ A / 1 m)

λ = 2.94 x 10¹⁰ A (in angstrom)

Answer:

1174.392 mph

Explanation:

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