1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kirill115 [55]
3 years ago
14

HELP PLS THIS IS DUE IN 15 MINUTES PLS PLS PLS!!! I WILL MARK BRAINLIEST IWTH THE BEST ANSWER!!!

Chemistry
2 answers:
jarptica [38.1K]3 years ago
7 0

Answer:

A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding.

Explanation:

mixer [17]3 years ago
3 0

Answer:

A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity.

physical changes are boiling, melting, freezing, and shredding.

Explanation:

You might be interested in
A compound is 42.9% C, 2.4% H, 16.7% N, and 38.1% O, by mass. Addition of 6.45 g of this compound to 50.0 mL benzene, lowers the
Romashka [77]

This is an incomplete question, here is a complete question.

A compound is 42.9% C, 2.4% H, 16.7% N and 38.1% O by mass. Addition of 6.45 g of this compound to 50.0 mL benzene, C₆H₆ (d= 0.879 g/mL; Kf= 5.12 degrees Celsius/m), lowers the freezing point from 5.53 to 1.37 degrees Celsius. What is the molecular formula of this compound?

Answer : The molecular of the compound is, C_6H_4N_2O_4

Explanation :

First we have to calculate the mass of benzene.

\text{Mass of benzene}=\text{Density of benzene}\times \text{Volume of benzene}

\text{Mass of benzene}=0.879g/mL\times 50.0mL=43.95g

Now we have to calculate the molar mass of unknown compound.

Given:

Mass of unknown compound (solute) = 6.45 g

Mass of benzene (solvent) = 43.95 g  = 0.04395 kg

Formula used :  

\Delta T_f=K_f\times m\\\\\Delta T_f=K_f\times\frac{\text{Mass of unknown compound}}{\text{Molar mass of unknown compound}\times \text{Mass of benzene in Kg}}

where,

\Delta T_f = change in freezing point  = 5.53-1.37=4.16^oC

\Delta T_s = freezing point of solution

\Delta T^o = freezing point of benzene

Molal-freezing-point-depression constant (K_f) for benzene = 5.12^oC/m

m = molality

Now put all the given values in this formula, we get

4.16^oC=(5.12^oC/m)\times \frac{6.45g}{\text{Molar mass of unknown compound}\times 0.04395kg}

\text{Molar mass of unknown compound}=180.6g/mol

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of C = 42.9 g

Mass of H = 2.4 g

Mass of N = 16.7 g

Mass of O = 38.1 g

Molar mass of C = 12 g/mole

Molar mass of H = 1 g/mole

Molar mass of N = 14 g/mole

Molar mass of O = 16 g/mole

Step 1 : convert given masses into moles.

Moles of C = \frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{42.9g}{12g/mole}=3.575moles

Moles of H = \frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{2.4g}{1g/mole}=2.4moles

Moles of N = \frac{\text{ given mass of N}}{\text{ molar mass of N}}= \frac{16.7g}{14g/mole}=1.193moles

Moles of O = \frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{38.1g}{16g/mole}=2.381moles

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = \frac{3.575}{1.193}=2.99\approx 3

For H = \frac{2.4}{1.193}=2.01\approx 2

For N = \frac{1.193}{1.193}=1

For O = \frac{2.381}{1.193}=1.99\approx 2

The ratio of C : H : N : O = 3 : 2 : 1 : 2

The mole ratio of the element is represented by subscripts in empirical formula.

The Empirical formula = C_3H_2N_1O_2

The empirical formula weight = 3(12) + 2(1) + 1(14) + 2(16) = 84 gram/eq

Now we have to calculate the molecular formula of the compound.

Formula used :

n=\frac{\text{Molecular formula}}{\text{Empirical formula weight}}

n=\frac{180.6}{84}=2

Molecular formula = (C_3H_2N_1O_2)_n=(C_3H_2N_1O_2)_2=C_6H_4N_2O_4

Therefore, the molecular of the compound is, C_6H_4N_2O_4

3 0
3 years ago
A beam balance is called a first class lever why?​
Dmitriy789 [7]

Answer:

A beam balance is an example of a first class lever.

Explanation:

A beam balance is an example of a first class lever. In a first class lever, the fulcrum is between the effort (force) and the load. The effort (force) moves over a large distance to move the load a smaller distance.

Other examples of first class lever are pliers, scissors, a crow bar, a claw hammer, a see-saw and a weighing balance etc.

8 0
2 years ago
Which statement is true of a
soldier1979 [14.2K]
I think the awnser to your question is C
6 0
3 years ago
Brenda rode a skateboard 95 meters west. It took her 20 seconds. What was
Artemon [7]

Answer:

D. 4.75 m/s west

Explanation:

You can immediately get the answer once you know the formula for<em> velocity.</em>

  • The formula for velocity is: Velocity (V) = \frac{distance (d)}{time (t)}

The distance is 95 meters while the time is 20 seconds. All you have to do is to divide <u>95 meters by 20 seconds</u>.

Let's solve:

  • V = \frac{d}{t}
  • V = \frac{95 meters}{20 seconds}
  • V = 4.75 meters per second

Since Brenda is going west with her her skateboard, then you have to add <em>west </em>as her direction.

Brenda's velocity is 4.75 m/s west.

5 0
3 years ago
ASAP!
Sav [38]

When a radioactive isotope releases an alpha particle, the atomic number of the atom is decreased by four.

So, the correct answer is B.

Hope this helps,

Davinia.

4 0
3 years ago
Other questions:
  • Which equation obeys the law of conservation of mass?
    14·2 answers
  • Identify the type of reaction, write the products with phases, and balance. Show all work.
    7·1 answer
  • A balanced chemical equation used to prepare ammonium carbonate, (nh4)2co3 , is: 2 n h 3 ( g ) + c o 2 ( g ) + h 2 o ( l ) ⟶ ( n
    9·1 answer
  • What occurs in a chemical reaction?
    6·2 answers
  • A piece of wood with a density of 0.85 g/cm^3 has a mass of 25 g. what is the volume of the wood?
    6·2 answers
  • Is "isotope" another name for an atom??
    12·2 answers
  • What did scientists mix to make the savanna cat
    10·2 answers
  • What is true about most of the wavelengths found in the electromagnetic spectrum?
    12·1 answer
  • An ice skater moves back and forth on an ice rink. She speeds up on the straight portion of the rink. She slows down near each e
    10·1 answer
  • Compare the boiling points of alcohol, ethers and alkanes and explain one reason for the difference
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!