A student placed a solid in a liquid, which produced the results shown in the following diagram.
solid: 20°C
OOO
gas bubbles
liquid: 20°C
1
2
Which of the following MOST likely took place?
A. a chemical reaction
chemical
o
O B. a phase change
C. a nuclear reaction
D. a destruction of mass

Answer:

Elements with short half lives exist because each element has stable isotopes, and the decay os isotopes create more isotopes as well.

Answer:

A. We still feel gravity because of inertia, which occurs all around us. Gravity is not felt as much because although it feels small, gravity is the attraction that keeps objects on Earth.

B. This is due to a field and a law, which states that opposites attract and like repel.

Answer:

%C= 42.1

%H=6.5

%O=51.4

Explanation:

Mass%=(mass/total)× 100%  

Answer: a

Explanation:

Bc I just did it and yeah

Answer:

Explanation:

B is the ans

pls mark BRAINLIEST

Answer:

1mpm(1 meters per minute) Explanation: Speed:Distance/time 25/25=1 plz mark as brainliest

Answer:

1mpm(1 meters per minute)

Answer:

d an acid - base reaction.

Explanation:

Answer:

single replacement

Explanation:Look it up and got it from quizlet it should be right.

Answer:

hope this help by the way found off of yahoo

Explanation:

Calculate the number of grams of nitrogen dioxide that are produced from

4 moles of nitric oxide.

2NO(g) + O2(g) -->2NO2(g)

I really need help with this... I need to know how to work it too... I can balance it out but not sure about grams...  This is it balanced out with 4 moles of nitric oxide

4NO(g) + 2O2(g) ->4NO2(g) please help and explain i want to learn this

Answer:

a, to reduce air bubbles

Explanation:

all its asking, is what is the purpose of the cover. and a is the most reasonable out of all of them, even though none of them make any sense.

Answer:

its both because your hight can change if u do exercises

Hope it helped.

Answer:

Approximately [tex]0.11823\; \rm g[/tex] in total for the five tablets.

(Approximately [tex]2.3646 \times 10^{-2}\; \rm g[/tex] per tablet.)

Explanation:

The relative atomic mass of an element is the ratio between:

The definition of moles ensures that the relative atomic mass of an element is approximately numerically equal to the mass (measured in grams) of one mole of the atoms of this element.

The question states that the relative atomic mass [tex]A_{\rm r}[/tex] of iron is [tex]56[/tex]. In other words, the mass of one mole of iron [tex]\rm Fe[/tex] atoms would be approximately [tex]56\; \rm g[/tex].

The question is asking for the mass of some amount of [tex]\rm Fe^{2+}[/tex] ions. Each [tex]\rm Fe^{2+}\![/tex] ion contains two fewer electrons than a neutral [tex]\rm Fe[/tex] atom. Hence, [tex]4.2225 \times 10^{4}\; \rm mol[/tex] of [tex]\rm Fe^{2+} \![/tex] ions might be lighter than the same number of [tex]\rm Fe \![/tex] atoms by a very small extent: The mass of one mole of electrons is approximately [tex]5 \times 10^{-4}\; \rm g[/tex], much smaller than the mass of the same number of [tex]\!\rm Fe[/tex] atoms (approximately [tex]56\; \rm g[/tex].)

Estimate the mass of these [tex]4.2225 \times 10^{4}\; \rm mol[/tex] of [tex]\rm Fe^{2+}[/tex] ions using the mass of the same number of [tex]\rm Fe[/tex] atoms:

[tex]\begin{aligned}&m({\rm Fe^{2+}}) \\ &\approx m({\rm Fe}) \\ &\approx 4.2225 \times 10^{-4}\; \rm mol \\ &\quad\quad \times 56\; \rm g \cdot mol^{-1} \\ &\approx 2.3646 \times 10^{-2}\; \rm g \end{aligned}[/tex].

Five of these tablets would contain approximately [tex]5 \times 2.3646 \times 10^{-2}\; \rm g \approx 0.11823\; \rm g[/tex] of [tex]\rm Fe^{2+}[/tex] ions.

Answer:

The molal concentration of the solution is approximately 0.124 molal

Explanation:

The given parameters are;

The reduced freezing point of the water = -0.23°C

For freezing point depression of a solution, we have;

[tex]\Delta T_f[/tex] = [tex]K_f[/tex]· b·i

Where;

[tex]\Delta T_f[/tex] = The freezing point depression

[tex]K_f[/tex] = Cyroscopic constant (The freezing-point depression constant) = 1.86° Cm⁻¹ for water

b = The molality of the solution

i = van't Hoff factor = 1

Therefore;

[tex]\Delta T_f[/tex] = [tex]T^{\circ}_f - T_f[/tex]

Where;

[tex]T^{\circ}_f[/tex] = The freezing point of pure water = 0°C

[tex]T_f[/tex] = The freezing point of the solution = -0.23°C

∴ [tex]\Delta T_f[/tex] = [tex]T^{\circ}_f - T_f[/tex] = 0°C - (-0.23°C) = 0.23 °C

From, [tex]\Delta T_f[/tex] = [tex]K_f[/tex]· b·i, we have;

0.23°C = 1.86°C/m × b × 1

∴ b  = (0.23°C/1.86°C/m) ≈ 0.124 molal

Therefore, the molal concentration of the solution, b ≈ 0.124 molal.

Answer:

Taxonomy

Explanation: Taxonomy formally names and classifies organisms by thier structure, function, and relationships

Answer:

B. increases the relative concentration of uranium-235 to 30-50% to avoid a nuclear explosion at higher percentages.

Explanation:

Uranium enrichment may be defined as a process which is necessary for creating effective nuclear fuel from the mined uranium by mainly increasing the percentage of the uranium-235 that undergoes fission with a thermal neutrons.

The enrichment process removes the unwanted uranium-238, thus making uranium 235 concentration higher. It takes up much work to increase the relative concentration of the uranium 235 to make it 30% to 50% so as to avoid a nuclear explosion at such higher percentages.

Answer:

i think its B

Explanation:

Answer:

because it is

Explanation:

simple

Answer:

Explanation: none

Answer:

Sr

Explanation:

because it's electronegativity is the highest.

Actually If you look very close to a plant you see this:

And to answer your question leaves are green due to sun nutrients water and im not sure  what else

Answer: The volume of the gas is 1.98 L.

Explanation:

To calculate the final volume of the system, we use the equation given by Charles' Law. This law states that volume of the gas is directly proportional to the temperature of the gas at constant pressure.

Mathematically,

[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}[/tex]

where,

[tex]V_1\text{ and }T_1[/tex] are the initial volume and temperature of the gas.

[tex]V_2\text{ and }T_2[/tex] are the final volume and temperature of the gas.

We are given:

[tex]V_1=2.2L\\T_1=30^oC=(30+273)K=303K\\V_2=?\\T_2=0^0C=(0+273)K=273K[/tex]

Putting values in above equation, we get:

[tex]\frac{2.2}{303}=\frac{V_2}{273}\\\\V_2=1.98L[/tex]

Thus the volume of the gas is 1.98 L

Answer:

wait are you talking about the bottom question??

[tex]\large \mathfrak{Solution : }[/tex]

volume = 12 ml = 0.012 litres = 0.012 cm³

mass = 6 g

And the relationship between mass, volume and density can be depicted by :

therefore, density = 500 g/cm³

Answer:

pH = 9

Explanation:

pOH = -log[OH-] = -log(1.0 x10^-5) = 5

pOH + pH = 14

pH = 14 - 5 = 9

In this exercise we have to use the knowledge of lunar eclipse to identify the alternatives that correspond to this effect, as follows:

A lunar eclipse happens when the Earth is between the Moon and the Sun, at times when they are aligned. Depending on the position of the Moon, it is total, partial or penumbral. Different stages of a lunar eclipse on a full moon night.

Now,  use the knowledge of solar eclipse to identify the alternatives that correspond to this effect, as follows:

Solar eclipse is an astronomical phenomenon that occurs when the Moon is positioned between the Earth and the Sun, hiding the light emitted by the star towards the planet.

See more about eclipse at brainly.com/question/25105283

Answer:

Electron dot structure

Explanation:

This is because electron dot structure is the structure that shows or indicate valence electrons of an atom and dots

is use around the element symbols . The number of dots shows the total number of valence electrons that are present in the atom of the molecules.

Answer:

Mitosis

Explanation:

Answer:

planets,meteoroids and asteroids  

Explanation: