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Olin [163]
3 years ago
6

NEED HELP! An experiment _____. must always be done in a laboratory is best done if only one variable is tested for at a time ca

n be done only by direct observation must always be done in the field
Chemistry
1 answer:
hichkok12 [17]3 years ago
6 0

Answer:

Chemically

in chemistry

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Which type of metal atoms affect the flame color ?
QveST [7]
The color emitted be larger atoms is lower in energy then the light emitted by smaller atoms
4 0
3 years ago
If 190dm of hydrogen gas collected at 20°c and 760mmHg .Calculate it's volume at stp (standard pressure=760mmHg
Andrei [34K]

Answer:

177.1 L

Explanation:

The excersise can be solved, by the Ideal Gases Law.

P . V = n . R . T

In first step we need to determine the moles of gas:

We convert T° from, C° to K → 20°C + 273 = 293K

We convert P from mmHg to atm → 760 mmHg = 1atm

1Dm³ = 1L → 190L

We replace: 190 L . 1 atm = n . 0.082 . 293K

(190L.atm) / 0.082 . 293K = 7.91 moles.

We replace equation at STP conditions (1 atm and 273K)

V = (n . R .T) / P

V = (7.91 mol . 0.082 . 273K) / 1atm = 177.1 L

We can also make a rule of three:

At STP conditions 1 mol of gas occupies 22.4L

Then, 7.91 moles will be contained at (7.91 . 22.4) /1 = 177.1L

3 0
3 years ago
Which element, when combined with Iodine, would most likely form an ionic compound?
uranmaximum [27]

In an ionic compound the atoms are linked via ionic bonds. These are formed by the transfer of electrons from one atom to the other. The atom that loses electrons gains a positive charge whereas the atom that accepts electrons gains a negative. This happens in accordance with the octet rule wherein each atom is surrounded by 8 electrons

In the given example:

The valence electron configuration of Iodine (I) = 5s²5p⁵

It needs only one electron to complete its octet.

In the given options:

K = 4s¹

C = 2s²2p²

Cl = 3s²3p⁵

P = 3s²3p³

Thus K can donate its valence electron to Iodine. As a result K, will gain a stable noble gas configuration of argon while iodine would gain an octet. This would also balance the charges as K⁺I⁻ creating a neutral molecule.

Ans: Potassium (K)

4 0
3 years ago
Caclulate the pH of a solution with a hydrogen ion concentration of 1X10-7
LUCKY_DIMON [66]

Answer:

The pH of the solution is 7.00 .

Explanation:

The pH gives us an idea of the acidity or basicity of a solution. More precisely, it indicates the concentration of H30 + ions present in said solution. The pH scale ranges from 0 to 14: from 0 to 7 corresponds to acid solutions, 7 neutral solutions and between 7 and 14 basic solutions. It is calculated as:

pH = -log (H30 +)

pH= -log (1x10^-7)

<em>pH= 7.00</em>

7 0
4 years ago
Investigations were carried out in a science lab to explore the topic of chemical and physical changes. Investigation A Step 1.
Angelina_Jolie [31]

Answer : B) In step 2, there was a chemical change which was observed in sugar.

Explanation : In A step 2 there was a physical change that was seen. By just boiling the dissolved salt solution salt was obtained. Therefore, it is a physical change. In B step 2 there was a chemical change seen as sugar solution was thickened and turned brown. It was not obtained in its original form; there was a chemical reaction that took place during sugar evaporation. As chemical change is the one where the reaction is irreversible.

Therefore only in B step 2 there was a chemical change that was observed.

4 0
3 years ago
Read 2 more answers
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