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3 years ago

8

An object in space is made of gas and gives off light and heat energy. We can only see it at night. Which object is it? (2 point

s)
Earth
moon
star
sun

1 answer:

strojnjashka [21]3 years ago

7 0

Answer:

stars

earth isn't made of gas. (and you can always see it)

moon us not gas, or give off heat

sun is only visible during the day

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Kamila [148]

Answer:

in the water, plants and small organisms like plankton take up mercury through passive surface absorption or through food intake. ... Methylmercury biomagnifies through the food chain as predators eat other organisms and absorb the contaminants that their food sources contained.

Explanation:n the water, plants and small organisms like plankton take up mercury through passive surface absorption or through food intake. ... Methylmercury biomagnifies through the food chain as predators eat other organisms and absorb the contaminants that their food sources contained.

4 0

2 years ago

What is the molarity of an HCl solution if 43.6 mL of a 0.125 M NaOH solution are needed to titrate a 25.0 mL sample of the acid

Sveta_85 [38]

Answer: The molarity of an HCl solution is 0.218 M if 43.6 mL of a 0.125 M NaOH solution are needed to titrate a 25.0 mL sample of the acid.

Explanation:

Given: $V_{1}$ = 43.6 mL, $M_{1}$ = 0.125 M

$V_{2}$ = 25.0 mL, $M_{2}$ = ?

Formula used to calculate the concentration of acid is as follows.

$M_{1}V_{1} = M_{2}V_{2}$

Substitute the values into above formula.

$M_{1}V_{1} = M_{2}V_{2}\\0.125 M \times 43.6 mL = M_{2} \times 25.0 mL\\M_{2} = 0.218 M$

Thus, we can conclude that the molarity of an HCl solution is 0.218 M if 43.6 mL of a 0.125 M NaOH solution are needed to titrate a 25.0 mL sample of the acid.

3 0

2 years ago

For Mn3+, write an equation that shows how the cation acts as an acid.

Mkey [24]

An acid is a compound which will give H+ ions or H3O^+ ions

the reaction will be

$[Mn(H_{2}O )_{6} ^{+3} +H_{2}O --> [MnOH(H_{2}O)_{5}]^{+2} + H_{3}O^{+}$

Thus as there is evolution of H_{3}O^{+} the Mn+3 is an acid

8 0

3 years ago

Read 2 more answers

What is the formula used to calculate the heat required to warm or cool one phase of matter

Ronch [10]

Answer:

SPECIFIC HEAT CAPACITY

Explanation:

Q = MC DELTA T

q = heat

c = specific heat

T = temperature ( final - initial )

4 0

3 years ago

Identify the neutral element represented by this excited-state electron configuration, then write the ground-state electron conf

sineoko [7]

Answer:

1s² 2s² 2p³

Nitrogen

Explanation:

Excited state configuration: 1s² 2s² 2p² 3s¹

Unknown:

Ground state configuration = ?

Element symbol = ?

Solution:

Let us start by understanding what a ground state configuration entails:

A ground state configuration shows the lowest allowed energy levels of an atom. The excited state denotes when electrons have moved to higher energy levels away from their ground state.

The superscript in the configuration depicts the number of electrons in each of the sublevels.

We can use this number to identify the atom we are dealing with:

Total number of electrons = 2 + 2 + 2 + 1 = 7 electrons

The element with 7 electrons on the periodic table is Nitrogen.

Now, the ground state configuration:

In writing the electronic configuration of an atom, certain rules must be complied with.

Aufbau's principle states that the sublevels with lower energies are filled up before those with higher energies. The order of filling is:

1s 2s 2p 3s 3p 4s etc

To fill the s-orbital = 2 electrons

p-orbital = 6 electrons

The outermost shell electrons are usually the ones excited.

Now, the 3s¹ shell is an excited one taking 1 electron from the second energy level;

The ground state configuration is 1s² 2s² 2p³

5 0

3 years ago