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Goshia [24]
3 years ago
5

What questions might remain that will one day be answered by new technology?

Chemistry
1 answer:
kumpel [21]3 years ago
5 0

Answer:

Can we find a safe cure for cancer?

Explanation:

pls mark brainliest

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Iron, a metal, has which of the following features?
Nastasia [14]

Answer: A sea of electrons

Explanation:

4 0
3 years ago
A freezer compartment is covered with a 2-mm-thick layer of frost at the time it malfunctions. If the compartment is in ambient
ruslelena [56]

Answer:

The time required to melt the frost is 3.25 hours.

Explanation:

The time required to melt the frost dependes on the latent heat of the frost and the amount of heat it is transfered by convection to the air .

The heat transferred per unit area can be expressed as:

q=h_c*A*\Delta T\\\\q/A=h_c*\Delta T

being hc the convective heat transfer coefficient (2 Wm^-2K^-1) and ΔT the difference of temperature (20-0=20 °C or K).

q/A=h_c*\Delta T=2\frac{W}{m^2K}*20K=40\frac{W}{m^2}

If we take 1 m^2 of ice, with 2 mm of thickness, we have this volume

V=T*A = 0.002 m * 1 m^2=0.002m^3

The mass of the frost can be estimated as

M=\rho * V=700\frac{kg}{m^3}*0.002m^3= 1.4 kg

Then,  the amount of heat needed to melt this surface (1 m²) of frost is

Q=L*M=334\frac{kJ}{kg}*1.4kg= 467.6kJ

The time needed to melt the frost can be calculated as

t=\frac{Q}{(q/A)}=\frac{467.6kJ/m2}{40W/m2} = 11.69\frac{kJ}{W}*\frac{1W*s}{1J}*\frac{1000J}{1kJ}=   11690s=3.25h

7 0
3 years ago
Las sustancias ionicas y los metale sson electricamente neutros. ¿como es esto posible si estan formados por iones, que posen ca
Anton [14]

Answer:

ver explicacion

Explanation:

Los iones se forman cuando las especies químicas pierden o ganan electrones.

Las sustancias iónicas consisten en un ión positivo y negativo cuyas cargas se equilibran exactamente entre sí, por lo que el compuesto iónico es neutro.

Los átomos de metal se mantienen unidos por el enlace metálico. Esto implica la interacción entre iones metálicos cargados positivamente y un mar de electrones negativos. Las cargas positivas de los iones metálicos están exactamente equilibradas por el mar de electrones cargados negativamente, por lo que el metal es neutro.

8 0
3 years ago
What is the electron configuration for 1s2 2s2 2p6 3s2 3p6​
Sliva [168]
This is going to lead you to the element Argon. Is this what you are asking?
7 0
2 years ago
(50 POINTS, PLEASE HELP!!) Go back and read the goals for this lesson on page 1. Form a summary statement for each goal, showing
kakasveta [241]

Answer:

An atom is made of up subatomic particles called protons, neutrons and electrons. The center of an atom is called the nucleus and is where the protons and neutrons are held while electrons orbit the nucleus in orbital shells. A electron has a negative charge, a proton has a positive charge, and a neutron has no charge (neutral).

The atomic number of a atom is the total amount of the atom's protons. In a neutral atom (Not an ion), the amount of electrons is the same as the protons. Therefore, the atomic number also tells the amount of electrons in the atom.

A ion is a negatively or positively charged particle due to the giving or taking of electrons with one or more atoms (Called an ionic bond). An atom that gives away electrons becomes positively charge because that atom now has more protons than neutrons. An atom that takes an electron becomes negatively charge because that atom now has more electrons than protons.

Atomic Mass is the sum of an atom proton and neutrons. To determine how many neutron an atom has, subtract the atomic mass from the atomic number. Electrons do not play a part in atomic mass as their mass is  1/1,836 of a proton's mass.

A isotope is two or more forms of the same element that contain equal amounts of protons but different amount of neutrons.

6 0
2 years ago
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