All categories

3 years ago

Why are chemical changes considered "unseen?"

2 answers:

6 0

Chemical changes are considered unseen because they occur at the atomic level, changing the actual structure of the thing. This is in comparison to a physical change, which is visible.

Andrej [43]3 years ago

5 0

Chemical changes are considered unseen because they occur at the atomic level, changing the actual structure of the thing.

You might be interested in

A volume of 80.0 mL of H2O is initially at room temperature (22.00 ∘C). A chilled steel rod at 2.00 ∘C is placed in the water. I

murzikaleks [220]

Answer:

The mass of the steel bar is 26.833 grams

Explanation:

Step 1: data given

ΣQ gained = ΣQ lost

Q=m*C*ΔT

with m = mass in grams

with C= specific heat capacity ( in J/(g°C))

with ΔT = change in temperature = T2-T1

Qsteel = Qwater

msteel * Csteel * (T2steel - T1steel) = mwater * Cwater * (T2water - T1water)

Mass of steel = TO BE DETERMINED

mass of water =⇒ since 1mL = 1g : 80 mL = 80g

Csteel =0.452 J/(g °C

Cwater = 4.18 J/(g °C

initial temperature steel T1 : 2 °C

final temperature steel T2 = 21.3 °C

initial temperature water T1 =22 °C

final temperature water T2 = 21.3 °C

Step 2: Calculate mass of steel

msteel * Csteel * (T2steel - T1steel) = mwater * Cwater * (T2water - T1water)

msteel * 0.452 *(21.3-2) = 80 * 4.18 * (21.3-22)

msteel = (80 * 4.18 * (-0.7)) / (0.452 * 19.3)

msteel = -234.08 / 8.7236

msteel = -26.833 g

Since mass can't be negative we should take the absolute value of it = 26.833g

The mass of the steel bar is 26.833 grams

6 0

3 years ago

What is smaller than one cell

mr_godi [17]

The organelles and substances inside the organelles are smaller. On a molecular level a group that are smaller are hadrons, which are the group of particles that consist of protons and neutrons. Even smaller than hadrons are leptons, which consist of neutrinos, electons, and MANY others.

6 0

3 years ago

Why ammonium is not a molecular ion

In-s [12.5K]

Answer:

See below

Explanation:

Ammonium $(NH_{4}^+)$ is not a molecular ion because it is just a poly-atomic ion. A molecular ion has a "negative or positive charge" as a whole but the positive charge on here is not on the whole. So, it is a poly-atomic ion and not molecular ion.

3 0

3 years ago

Equation 3x-5=-2x+ 10? O 0 x= 5 -5 = x -15 = -5x -5x = 15

Harman [31]

Answer:

are those the answer choice

7 0

3 years ago

What happens to the electronegativity as you go from Lithium to Francium? Why?

Y_Kistochka [10]

Answer:

Electronegativity in group 1 decreases as we go from Lithium to Francium.

Explanation:

Electronegativity is defined as the tendency of an element to attract an electron pair towards itself.

In a group generally this tendency decreases from top to bottom as the size of the atom increases and hence the positive nucleus get far from the outer orbital.

In the same way group 1 elements i.e. from Lithium to Francium electronegativity decreases.

8 0

3 years ago