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rewona [7]
3 years ago
7

A student has a sample of solid calcium. It is shiny and metallic looking. He squeezes a pipet of concentrated sulfuric acid ont

o the calcium. Bubbles are produced and the calcium appears to disappear. The test tube gets hot. What kind of change occurred?
Chemistry
1 answer:
Nikitich [7]3 years ago
4 0

Answer:

Physical change

Explanation:

There are two types of changes: physical change and chemical change. Physical change is defined as the change that changes the physical appearance of the substance and do not affcet the chemical composition of the substance whereas chemical change causes changes in the chemical composition of the susbstance.

The given example shows physical change because solid calcium undergoes sublimation. process in which a solid substance changes into gaseous phase directly without undergoing liquid phase.

Hence, the correct answer is "Physical change".

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What is the relation between celsius and kelvin?
kogti [31]
0 degree Celsius is equal to 272 k
So to convert C to k we need to add 273
To convert K to C we need to subtract 273
4 0
3 years ago
Based on the graph below, if you chose an alien at random on day 20, what form would it most likely be in?
ArbitrLikvidat [17]

Answer:

A. Thin

Explanation:

i took the test a while back yw <3

4 0
3 years ago
Different kinds of wood have different densities. The density of american white oak wood is generally 0.77 g/cm3. If Jim grabs a
mixas84 [53]

Answer:

m= 29.645 g

Explanation:

Density:

Density is equal to the mass of substance divided by its volume.

Units:

SI unit of density is Kg/m3.

Other units are given below,

g/cm3, g/mL , kg/L

Formula:

D=m/v

D= density

m=mass

V=volume

Symbol:

The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.

Given data:

density of wood = 0.77 g/cm³

volume= 38.5 cm³

mass= ?

Solution:

d= m/v

m= d × v

m= 0.77 g/cm³× 38.5 cm³

m= 29.645 g

7 0
3 years ago
A. List the potential acute health effects.
AleksandrR [38]

When we handle chemical substances we must be very careful because they can put our:

  • Physical integrity.
  • Health
  • Life at risk.

<h3>What is a chemical?</h3>

A chemical substance is a chemical compound resulting from the union of two or more chemical elements. Compounds have different uses depending on their properties. However, some can be harmful and life-threatening to humans.

<h3>Potential acute effects.</h3>

The potential acute effects of some compounds may be related to skin contact causing:

  • Inflammation
  • Redness
  • Rash
  • Burns
  • Dry
  • Among other.

On the other hand, the chronic effects of chemical compounds can be:

  • Diseases in the central nervous system.
  • Respiratory diseases.
  • Skin diseases.
  • Degenerative diseases of the bone system.

<h3>What to do when a chemical is ingested?</h3>

There are a large number of chemical substances and each one has different properties. Therefore, it is very difficult to generalize about a treatment in case of ingestion. What must be done is to know the level of risk of the substance that is being handled and avoid ingesting it at all costs. However, if it is ingested, go to the emergency room.

<h3>Product flammability</h3>

Not all chemical compounds have the same flammable response to fire. Due to the above, it is necessary to identify if the substance that we are handling is highly or slightly flammable, for this we can consult the manual of the substance or the label of its packaging.

<h3>3 Chemical that produces a potentially dangerous reaction with hydrochloric acid.</h3>

According to some studies and the hydrochloric acid safety data sheet, it can have dangerous reactions with:

  • Reacts violently with water.
  • Gives off hydrogen in reaction with metals.
  • Keep away from strong bases.

<h3>How to handle small spills?</h3>
  • Contain the spill.
  • Soak up with inert absorbent material.
  • Prevent the product from entering the sewage system.
  • Keep in suitable, closed containers for disposal.

<h3>Personal Protection</h3>

When we handle chemical substances we are facing a potential risk. Due to the above, protocols have been developed for its handling, which include the use of protection elements such as:

  • Gloves
  • Glasses
  • Helmet
  • Mask
  • Boots
  • Special suit.
  • Among others.

Learn more about chemical compounds in: brainly.com/question/14498747

5 0
2 years ago
A mixture of gases is analyzed and found to have the following composition in mol %: CO2 12.0 CO 6.0 CH4 27.3 H2 9.9 N2 44.8 a)
vichka [17]

Answer:

a) CO₂: <em>21,9%; </em>CO: <em>7,0%; </em>CH₄: <em>18,2%; </em>H₂: <em>0,8%; </em>N₂: <em>52,1%</em>

b) 24,09 g/mol

Explanation:

a) It is posible to obtain the composition of the gas mixture in weight% using molecular mass of each compound, thus:

12% CO₂×\frac{44,01g}{1mol} = <em>528,1 g</em>

6% CO×\frac{28,01g}{1mol} = <em>168,1 g</em>

27,3% CH₄×\frac{16,05g}{1mol} = <em>438,2 g</em>

9,9% H₂×\frac{2,02g}{1mol} = <em>20,0 g</em>

44,8% N₂×\frac{28g}{1mol} = <em>1254,4 g</em>

The total mass of the gas mixture is:

528,1g + 168,1g + 438,2g + 20,0g + 1254,4g = <em>2408,8 g</em>

Thus composition of the gas mixture in weight% is:

CO₂: \frac{528,1g}{2408,8g}×100 = <em>21,9%</em>

CO: \frac{168,1g}{2408,8g}×100 = <em>7,0%</em>

CH₄: \frac{438,2g}{2408,8g}×100 = <em>18,2%</em>

H₂: \frac{20,0g}{2408,8g}×100 = <em>0,8%</em>

N₂: \frac{1254,4g}{2408,8g}×100 = <em>52,1%</em>

b) The average molecular weight of the gas mixture is determined with mole % composition, thus:

0,12×44,01g/mol + 0,06×28,01g/mol + 0,273×16,05g/mol + 0,099×2,02g/mol + 0,448×28g/mol = <em>24,09 g/mol</em>

I hope it helps!

6 0
3 years ago
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