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2 years ago

Please help!

Chemistry

2 answers:

ANEK [815]2 years ago

8 0

Answer:

A- Physical, B- Chemical, C- chemical, D- Physical

Explanation:

A is physical because you can see it changing its form is changing.

B is Chemical because a new substance is formed creating the orange color of rust.

C is a Chemical reaction because it is being broken down so the banana itself is changing not just how we see it.

D is physical because we are just changing the shape/ size of the item, not anything to do with its substances.

motikmotik2 years ago

8 0

Answer:

a. physical change, it is reverse reversible since no new substance is created.

b.chemical change, The iron reacts with water and oxygen to form hydrated iron(III) oxide, which we see as rust.

c. chemical change, Bananas contain compounds known as polyphenol oxidases and iron-containing chemicals. These chemicals react with oxygen to turn the fruit brown.

d. physical change, there is no new substance created, and there is no change in the original composition of wood.

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Use the periodic table to identify the element with the electron configuration 1s²2s²2p⁴. Write its orbital diagram, and give th

natta225 [31]

Answer:

1. Orbital diagram

2p⁴ ║ ↑↓ ║ "↑" ║ ↑

2s² ║ ↑↓ ║

1s² ║ ↑↓ ║

2. Quantum numbers

n = 2,
l = 1,

$m_{l}$ = 0,

$m_{s}$ = +1/2

Explanation:

The fill in rule is:

Follow shell number: from the inner most shell to the outer most shell, our case from shell 1 to 2

Follow the The Aufbau principle, 1s<2s<2p<3s<3p<4s<3d<4p<5s<4d<5p<6s<4f<5d<6p<7s<5f<6d<7p
Hunds' rule: Every orbital in a sublevel is singly occupied before any orbital is doubly occupied. All of the electrons in singly occupied orbitals have the same spin (to maximize total spin).

So, the orbital diagram of given element is as below and the sixth electron is marked between " "

2p⁴ ║ ↑↓ ║ "↑" ║ ↑

2s² ║ ↑↓ ║

1s² ║ ↑↓ ║

The quantum number of an electron consists of four number:

n (shell number, - 1, 2, 3...)
l (subshell number or orbital number, 0 - orbital s, 1 - orbital p, 2 - orbital d...)
$m_{l}$ (orbital energy, or "which box the electron is in"). For example, orbital p (l = 1) has 3 "boxes", it was number from -1, 0, 1. Orbital d (l = 2) has 5 "boxes", numbered -2, -1, 0, 1, 2
$m_{s}$ (spin of electron), either -1/2 or +1/2

In our case, the electron marked with " " has quantum number

n = 2, shell number 2,
l = 1, subshell or orbital p,

$m_{l}$ = 0, 2nd "box" in the range -1, 0, 1

$m_{s}$ = +1/2, single electron always has +1/2

3 0

4 years ago

Find the mass of an object on earth if its weight is 100N

Kaylis [27]

Answer:

0.19 kg

8 N

1.964 N

58.86 N

15 kg

Explanation:

w = Weight of an object = 100 N

g = Acceleration due to gravity of Earth = $9.81\ \text{m/s}^2$

m = Mass of an object

Weight is given by

$w=mg\\\Rightarrow m=\dfrac{w}{g}\\\Rightarrow m=\dfrac{100}{9.81}\\\Rightarrow m=10.19\ \text{kg}$

Mass of the object is 0.19 kg

g = $2\ \text{m/s}^2$

m = 4 kg

$w=mg\\\Rightarrow w=4\times 2\\\Rightarrow w=8\ \text{N}$

Weight of the object is 8 N.

m = 200 g

$w=mg\\\Rightarrow w=0.2\times 9.81\\\Rightarrow w=1.964\ \text{N}$

Weight of the object is 1.964 N.

Weight is the force the Earth exerts on an object which is on the surface of the Earth.

m = 6kg

$w=mg\\\Rightarrow w=6\times 9.81\\\Rightarrow w=58.86\ \text{N}$

The force of the object is 58.86 N.

w = 150 N

a = g = $10\ \text{m/s}^2$

$m=\dfrac{w}{g}\\\Rightarrow m=\dfrac{150}{10}\\\Rightarrow m=15\ \text{kg}$

Mass of the object is 15 kg.

7 0

3 years ago

Is aluminium malleable or rigid?

grandymaker [24]

Aluminum is malleabe

4 0

3 years ago

What is the pH of 0.26 M ammonium ion? NH4+(aq) + H2O(1) NH3(aq) + H30* (aq) a. 4.33 b.9.25 c. 3.87 d. 4.92 e. 4.75

choli [55]

Answer:

b) pH = 9.25

Explanation:

NH4+(aq) + H2O(l) ↔ NH3(aq) + H3O+(aq)
NH3 + H2O ↔ NH4+ + OH-
2 H2O ↔ H3O+ + OH-

⇒ Kb = [ NH4+ ] * [ OH- ] / [ NH3 ] = 1.86 E-5......from literature

mass balance NH4+:

⇒ M NH4+ = [ NH4+ ] - [ OH- ]

∴ [ NH3 ] ≅ M NH4+ = 0.26 M

⇒ Kb = (( 0.26 + [ OH- ] )) * [ OH- ] / 0.26 = 1.86 E-5

⇒ 0.26 [ OH-] + [ OH- ]² = 4.836 E-6

⇒ [ OH- ]² + 0.26 [ OH- ] - 4.836 E-6 = 0

⇒ [ OH- ] = 1.859 E-5 M

⇒ pOH = - Log ( 1.859 E-5 )

⇒ pOH = 4.7305

⇒ pH = 14 - pOH = 9.269

6 0

3 years ago

(-15)+(-12)+14 how do u simplify

Lena [83]

Answer:

-15-12-14=-13

Explanation:

we simplify by opening the bracket

5 0

3 years ago