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tester [92]
3 years ago
9

Which statements are true about physical changes? Select all that apply.

Chemistry
1 answer:
Vadim26 [7]3 years ago
6 0

Answer:

a

Explanation:

because physical changes are reversible while chemical changes are irreversible

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Which of the following statements is TRUE?
Flura [38]

Answer:

c. An ionic bond is much stronger than most covalent bonds

Explanation:

Ionic bonds are interatomic bonds that forms as a result of electrostatic attraction between two ions. For an ionic bond to be formed, one atom must have lost or gained electron from another that is transferring it. Ionic bonds typically form between atoms whose electronegativity differences are far apart.

Ionic bonds are usually stronger than other types of bonds due to the electrostatic attraction between ions.

One very distinct feature about ionic compounds is that they are conductors of electricity in either molten or aqueous. At room temperature, they are solids and contains no mobile ions.

7 0
3 years ago
If my primary DNA strand is ATACCGCAA <br> a write the complimentary DNA strand
Liula [17]

Answer:

TATGGCGTT

Explanation:

Complimentary base pairs:

A-T

C-G

Use the other letter for complimentary strands

6 0
3 years ago
Read 2 more answers
Which of the following is a balanced equation?<br><br>Select one:<br>a. A<br>b. B<br>c. C<br>d. D​
Phantasy [73]

Answer:

B

Explanation:

Balanced equations have the same number of elements on both sides. If the number of elements are equal to each other for every element in the equation on both sides, then the equation is balanced.

Important concept : The big number before an element or compound represents how many molecules of that compound or element there are in a reaction. To find the number of atoms of each element you multiply the coefficient by the subscript ( small number ) which represents the number of atoms of that element in each molecule. Ex. 3H2O. There is a coefficient of 3 meaning that there are 3 molecules of H2O. There is a subscript after H meaning there are 2 atoms of hydrogen in each molecule. To find the total number of atoms we multiply the subscript of hydrogen by the coefficient of the whole molecule. 3 * 2 = 6 , so there are a total of 6 atoms of hydrogen in 3H2O

A) Cu + 2AgNO3 ==> CuNO3 + 2Ag

                    1   Cu  1

                    2   Ag  2

                     2   N  1

                     3  O   3

The amount of nitrogen atoms is different on both sides of the equation therefore this is not a balanced equation

B) CCl4 + O2 ==> CO2 + 2Cl2

                     1  C  1

                     4  Cl  4

                     2  O  2

The number of atoms of each element is the same on both sides of the equation therefore this is the balanced equation, however lets check the other answer choices just in case.

C)  2K + H2SO4 ==> K2SO4 + 2H2

                        2  K   2

                        1   H   4

                        1   S    1

                        4  O   4

The number of Hydrogen atoms are different on each side of the equation therefore this is not a balanced equation.

D) 2Al2O3 ==> 2Al + 3O2

              4  Al  2

              6  O  6
There are a different amount of aluminum atoms on both sides of the equation therefore this is not a balanced equation.

               

3 0
2 years ago
What volume of a 1.5 M KOH solution is needed to provide 3.0 moles of KOH?
Brums [2.3K]

Answer:

  • Volume = <u>2.0 liter</u> of 1.5 M solution of KOH

Explanation:

<u>1) Data:</u>

a) Solution: KOH

b) M = 1.5 M

c) n = 3.0 mol

d) V = ?

<u>2) Formula:</u>

Molarity is a unit of concentration, defined as number of moles of solute per liter of solution:

  • M = n / V in liter

<u>3) Calculations:</u>

  • Solve for n: M = n / V ⇒ V = n / M

  • Substitute values: V = 3.0 mol / 1.5 M = 2.0 liter

You must use 2 significant figures in your answer: <u>2.0 liter.</u>

8 0
3 years ago
How does black and coloured objects absorb light and convert it into heat?
Nezavi [6.7K]

Answer:

Light energy can be converted into heat energy. A black object absorbs all wavelengths of light and converts them into heat, so the object gets warm. A white object reflects all wavelengths of light, so the light is not converted into heat and the temperature of the object does not increase noticeably.

5 0
2 years ago
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