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2 years ago

Is a graph that starts at 25 and drops to 21, stays the same in temperature an endothermic reaction or an exothermic reaction?

Chemistry

1 answer:

ki77a [65]2 years ago

5 0

Answer:

Explanation:

Endo and Exo thermic are defined by what changes take place in the environment of the reaction.

If the temperature goes up, the reaction is giving up heat. It is Exothermic.

If the temperature goes down, the reaction requires heat. It is Endothermic.

In this case, the temperature went down. The reaction is Endothermic.

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Three substances A, B, and C melt at 00C,500C and -1500C

Drupady [299]

Answer:

That information is better presented and analyzed in a table.

This table shows you all the information and the answers:

Substance         melting point   boiling point    room temperature    conclusion
                                    °C                  °C                      °C                (state)

A                                  0                    100                    25                    liquid

B                                  50                  200                    25                    solid
C                               -150                   10                 25                    gas

Explanation:

1) Substance A at 25° is above the melting point and below the boiling point, then it is liquid (just like water)

2) Substance B at 25°C is below the melting point, so it is solid.

3) Substance C at 25°C is above the boiling point, so it is gas.

7 0

3 years ago

Determine the number of atoms in 41.0 grams of calcium, Ca. (The mass of one mole of calcium is 40.08 g.)

Dovator [93]

Hi there!

Let me know if you have questions about my answer:

6.15 × 10²⁴

Explanation:

To find the number of atoms, divide the mass of calcium (m) by its molar mass (MM). This will give you the number of moles of calcium (n).

$n = m/MM$ Start with a formula

$=\frac{41.0g}{40.08g/mol}$ Substitute values from the question

$= \frac{41.0g*1mol}{40.08g}$ Simplify

$= \frac{41.0mol}{40.08}$ Cancel out the units "g"

$= 1.022...mol$ Number of moles of calcium, with 4 significant figures

Then, multiply the number of moles of calcium (n) by Avogadro's number ( $N_{A}$ ) to find the number of calcium atoms.

$Number.of.Ca=n*N_{A}$ Start with a formula

$= 1.022mol*\frac{6.022*10^{23}Ca}{1mol}$ Substitute values from the question

$= \frac{1.022mol*6.022*10^{23}Ca}{1mol}$ Simplify

$= 1.022*(6.022*10^{23}Ca)$ Cancel out the units "mol"

$= 6.154*10^{24} Ca$ Multiply, leave one extra digit to help round. "4" tells you to round down.

$= 6.15*10^{24} Ca$ Final answer to 3 significant figures*

*When multiplying and dividing numbers, your final answer will have the same number of significant figures as the number with the least number of significant figures in the question.

40.08 has 4 significant figures. 41.0 has 3 significant figures. So, you want 3 significant figures in your final answer.

I hope this helps!

Learn more about Avogadro's number here:

brainly.com/question/1445383

Check out another answer that uses significant figures:

brainly.com/question/3721164

7 0

2 years ago

what happens when an object speeds up,slows down, or changes direction A) velocity B) time C) deceleration D) acceleration

HACTEHA [7]

Whenever the motion of an object changes . . . speeding up, or slowing down,
or changing direction . . . that change is called "acceleration". Acceleration is produced by force on the object.If there is no force on the object, then there is no acceleration. That means that
its motion doesn't change. The object remains in constant, uniform motion .
moving with steady speed, in a straight line.

No force is necessary to keep an object moving, only to change its motion.

3 0

2 years ago

Read 2 more answers

what is the maximum number of covalent bonds that an oxygen atom with atomic number 8 can make with hydrogen? question 4 options

Oliga [24]

Maximum number of covalent bonds that an oxygen atom can make with hydrogen is 2.

the ground state electronic configuration of oxygen is 2s² 2p⁴ that means it has 6 electrons in its valence shell and require two electrons are required to complete its octate.
Two bonds are created when an electron donor atom shares the two needed electrons with oxygen. The ability of two oxygen atoms to share valence electrons results in the creation of a double bond between the two atoms.
There are no longer any empty orbitals in the octet of oxygen after it is complete. As a result, it is unable to accept more electrons or create more bonds.

Therefore, Oxygen can only generate two bonds because it needs two additional electrons to complete its octet, after which it will run out of empty orbitals in which to receive additional electrons and create additional bonds.

learn more about octate here:

https://brainly.in/question/24161245

#SPJ4

3 0

1 year ago

What is the steric number of H2O2?

chubhunter [2.5K]

Answer: 1(2)+6(2)=14

Explanation:

Not sure, but maybe.

8 0

3 years ago