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3 years ago

How many electron shells does an atom of oxygen have? (A.) 1 (B.) 2 (C.) 3 (D.) 4

Physics

2 answers:

Vladimir79 [104]3 years ago

8 0

It has two electrons

Otrada [13]3 years ago

3 0

The answer is c 2 hope this helped

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When astronomers observe the spectra of distant galaxies,they notice that the hydrogen emission lines are shifted noticeably tow

34kurt

The amount of redshift increases in relation with the distance, meaning, the larger the redshift, the more distant the galaxy. The Hubble diagram which was created by Edwin Hubble in 1929 shows that the more redshifted a galaxy is the further away it is. The galaxies are moving away from Earth because the fabric of space itself is expanding. Subtle changes in the color of starlight let astronomers find planets, measure the speeds of galaxies, and track the expansion of the universe.

5 0

4 years ago

A 50 g copper calorimeter contains 250 g of water at 20 C. How much steam be condensed into the water to make the final temperat

Nostrana [21]

Answer:

Approximately $13\; \rm g$ of steam at $100\; \rm ^\circ C$ (assuming that the boiling point of water in this experiment is $100\; \rm ^\circ C\!$ .)

Explanation:

Latent heat of condensation/evaporation of water: $2260\; \rm J \cdot g^{-1}$ .

Both mass values in this question are given in grams. Hence, convert the specific heat values from this question to $\rm J \cdot g^{-1}$ .

Specific heat of water: $4.2\; \rm J \cdot g^{-1}\cdot \rm K^{-1}$ .

Specific heat of copper: $0.39\; \rm J \cdot g^{-1}\cdot K^{-1}$ .

The temperature of this calorimeter and the $250\; \rm g$ of water that it initially contains increased from $20\; \rm ^\circ C$ to $50\; \rm ^\circ C$ . Calculate the amount of energy that would be absorbed:

$\begin{aligned}& Q(\text{copper}) \\ =\;& c \cdot m \cdot \Delta t \\ =\;& 0.39\; \rm J \cdot g^{-1}\cdot K^{-1} \times 50\; \rm g \times (50\;{\rm ^\circ C} - 20\;{\rm ^\circ C}) \\ =\; & 585\; \rm J \end{aligned}$ .

$\begin{aligned}& Q(\text{cool water}) \\ =\;& c \cdot m \cdot \Delta t \\ =\;& 4.2\; \rm J \cdot g^{-1}\cdot K^{-1} \times 250\; \rm g \times (50\;{\rm ^\circ C} - 20\;{\rm ^\circ C}) \\ =\; & 31500\; \rm J \end{aligned}$ .

Hence, it would take an extra $585\; \rm J + 31500\; \rm J = 32085\; \rm J$ of energy to increase the temperature of the calorimeter and the $250\; \rm g$ of water that it initially contains from $20\; \rm ^\circ C$ to $50\; \rm ^\circ C$ .

Assume that it would take $x$ grams of steam at $100\; \rm ^\circ C$ ensure that the equilibrium temperature of the system is $50\; \rm ^\circ C$ .

In other words, $x\; \rm g$ of steam at $100\; \rm ^\circ C$ would need to release $32085\; \rm J$ as it condenses (releases latent heat) and cools down to $50\; \rm ^\circ C$ .

Latent heat of condensation from $x\; \rm g$ of steam: $2260\; {\rm J \cdot g^{-1}} \times (x\; {\rm g}) = (2260\, x)\; \rm J$ .

Energy released when that $x\; {\rm g}$ of water from the steam cools down from $100\; \rm ^\circ C$ to $50\; \rm ^\circ C$ :

$\begin{aligned}Q = \;& c \cdot m \cdot \Delta t \\ =\;& 4.2\; {\rm J \cdot g^{-1}\cdot K^{-1}} \times (x\; \rm g) \times (100\;{\rm ^\circ C} - 50\;{\rm ^\circ C}) \\ =\; & (210\, x)\; \rm J \end{aligned}$ .

These two parts of energy should add up to $32085\; \rm J$ . That would be exactly what it would take to raise the temperature of the calorimeter and the water that it initially contains from $20\; \rm ^\circ C$ to $50\; \rm ^\circ C$ .

$(2260\, x)\; {\rm J} + (210\, x)\; {\rm J} = 32085\; \rm J$ .

Solve for $x$ :

$x \approx 13$ .

Hence, it would take approximately $13\; \rm g$ of steam at $100\; \rm ^\circ C$ for the equilibrium temperature of the system to be $50\; \rm ^\circ C$ .

4 0

3 years ago

Which of the following factors will negatively impact the rate of diffusion of a molecule?

Maurinko [17]

Answer:

A low difference in the concentration of the molecule across the media

Explanation:

Diffusion is a type of passive transport where the molecules move in the influence of concentration gradient of diffusing molecules i.e. from the higher concentration region to the lower concentration region. There are some factors which affect the rate of diffusion, these are written below -

Mass of diffusing molecule - lighter molecules diffuse faster and heavier one diffuse relatively slower.
Concentration gradient - rate of diffusion is higher if the difference in concentration of the diffusing particles is larger in the two regions.
Distance traveled - molecules diffuse faster if they need to travel little distance during diffusion.
Temperature - rate of diffusion will be greater at higher temperatures because the movement of diffusing molecules gets increased.
Solvent density - rate of diffusion tend to be lower if the solvent has higher density.

Looking at these factors we can conclude that the second statement in the question tells about a negative impact regarding the diffusion because due to low difference in concentration across the two media, the rate of diffusion will be lower.

3 0

3 years ago

which of the folloing statements about ionization energy is true? A elements toward the bottom of a group periodic table general

beks73 [17]

accept the flow of electrons.resist the flow of electrons.accept the flow of protons.resist the flow of protons.It is one of these

6 0

3 years ago

Someone please answer this, ill give you brainliest and your earning 50 points.

Tema [17]

All of the following are non-renewable resources except

O natural gas

O oil

O minerals

O water ✓ 

Water is a renewable source because evaporation and condensation takes place everytime on our planet

3 0

2 years ago

Read 2 more answers