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3 years ago

15

18 Powdered sulfur is yellow, and powdered iron is gray. When powdered sulfur and powdered iron are mixed at 20°C, the powdered

iron
(1) becomes yellow (3) remains ionic
(2) becomes a liquid (4) remains magnetic

1 answer:

MAXImum [283]3 years ago

7 0

Powered sulfur is yellow, and powdered iron is gray. When powered sulfur are mixed at 20 degrees C, the powered iron remains magnetic.

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What is the change in internal energy (ΔΕ) of a system when 5 kJ of work is done on the system while it releases 13 kJ of energy

meriva

The change in internal energy (ΔΕ) of a system : -8 kJ

<h3>Further explanation </h3>

The laws of thermodynamics 1 state that: energy can be changed but cannot be destroyed or created

The equation is:

$\tt \Delta U=Q+W$

Energy owned by the system is expressed as internal energy (U)

This internal energy can change if it absorbs heat Q (U> 0), or releases heat (U <0). Or the internal energy can change if the system does work or accepts work (W)

The sign rules for heat and work are set as follows:

• The system receives heat, Q +

• The system releases heat, Q -

• The system does work, W -

• the system accepts work, W +

5 kJ of work is done on the system : W = +5 kJ

releases 13 kJ of energy to the surroundings : Q = -13 kJ

$\tt \Delta E=-13+5=-8~kJ$

6 0

2 years ago

Differentiate between the three types of simple permanent tissues on the basis of their cell walls

True [87]

Answer:

Parenchyma is the most simple and specialized tissue which is concerned mainly with the vegetative activities of the plant. The cells are isodiametric with well-developed intercellular spaces, vacuolated cytoplasm and cellulosic cell wall.

Collenchyma is the tissue of the primary body. The cells of the tissue contain protoplasm and are living without intercellular spaces. The cell wall articulate at the corners and are made up of cellulose, hemicellulose, and pectin.

Sclerenchyma is the thick-walled cell tissue. In the beginning, the cell is living and have protoplasm, but due to deposition of impermeable secondary board lignin, they become dead thick and hard.

5 0

3 years ago

A sample of 53.0 of carbon dioxide was obtained by heating 1.31 g of calcium carbont. What is the percent yield for this reactio

MaRussiya [10]

Answer:

92.04%

Explanation:

Given:

Mass of CO₂ obtained = 53.0 grams

Mass of calcium carbonate heated = 1.31 grams

Now,

the molar mass of the calcium carbonate = 100.08 grams

The number of moles heated in the problem = Mass / Molar mass

= (1.31 grams) / (100.08 grams/moles)

= 0.013088 moles

now,

1 mol of calcium carbonate yields 1 mol of CO₂

thus,

0.013088 moles of calcium carbonate will yield = 0.013088 mol of CO₂

now,

Theoretical mass of 0.013088 moles of CO₂ will be

= Number of moles × Molar mass of CO₂

= 0.013088 × 44 = 0.5758 grams

Thus, the percent yield for this reaction = $\frac{\textup{Actual yield}}{\textup{Theoretical yield}}\times100$

or

the percent yield for this reaction = $\frac{0.53}{0.5758}\times100$

or

the percent yield for this reaction = 92.04%

6 0

3 years ago

Is 2OH−+Ca2+−>2Ca(OH)2 balanced

wariber [46]

Answer:

No.

Explanation:

No. There is 1 atom of Ca on the left and 2 Ca's on the right and 2 OH's on the left and 4 on the right.

The balanced equation is:

4OH- + 2Ca2+ ----> 2Ca(OH)2.

3 0

2 years ago

Read 2 more answers

Osmotic pressure ____.a. occurs only in ionic solutions.b. is lower with 1 M NaCl than 1 M sucrose.c. is created using detergent

Firdavs [7]

Answer:

d. is the hydrostatic pressure produced on the surface of a semi-permeable membrane by osmosis.

Explanation:

Osmosis -

It is the flow of the molecules of solvent from a region of higher concentration towards the region of lower concentration via a semipermeable membrane , is known as osmosis.

Osmotic pressure -

It refers to the minimum amount of pressure , which is required to be applied to the solution in order to avoid the flow of pure solvent via the semipermeable membrane , is referred to as osmotic pressure.

Or in simple terms ,

Osmotic pressure is the pressure applied to resists the process of osmosis.

Hence ,

From the given options in the question,

The correct option regarding osmotic pressure is d.

6 0

3 years ago