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4 years ago

Which of the following best explains the position of the two atoms in the periodic table? (4 points)

1 answer:

3 0

The position of a given element in the periodic table depends on the atomic number. Further the atomic number is equal to the number of protons and the number of electrons of the particular element.

Also for the considered element, depending on the atomic number, the placement in the periodic table will create groups (columns) and periods (rows).

As a example we will take two atoms carbon (C) and nitrogen (N):

carbon (C) - has a atomic number of 6, it contains 6 protons and 6 electrons, and you find this element in the group 14 and period 2 in the periodic table

nitrogen (N) - has a atomic number of 7, it contains 7 protons and 7 electrons, and you find this element in the group 15 and period 2 in the periodic table

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The machine the measures the strength of an earthquake is called...

Elina [12.6K]

B; Seismometer would be the answer.

4 0

3 years ago

What would you need to do to calculate the molality of 10 g of NaCl in 2 kg of

jasenka [17]

Answer:

O B. Convert the 10 g of NaCl to moles of NaCl.

Explanation:

The formula for finding the molality is m=moles of solute/kg of solvent. The solute for this question is NaCl and the solvent is water.

(10g NaCl)(1 mol NaCl/58.44g NaCl)=0.1711 mol NaCl

58.44 is the molar mass of NaCl

m=0.1711 mol NaCl/2 kg H2O

m=0.085557837

7 0

3 years ago

Using the SDS, write the major hazard of concentrated HCL

shusha [124]

Answer:

According to the Safety Data Sheet (SDS), the major harzard of concentrated HCl is that it may cause severe burns to skin, eyes and mucous membranes.

Explanation:

The SDS also informs that:

Most Important Hazards:

May cause severe burns to skin, eyes and mucous membranes.

 Steam produced is irritating.

 Pollution of rivers and water bodies by changing the pH. Affects flora and fauna that comes in contact with acid.

Product Effects:

 If in direct contact with eyes will cause serious burns and vision loss.

Adverse effects to human health:

 Inhalation causes severe respiratory tract irritation. May cause pulmonary edema. The contact with the skin causes burns, which can lead to dermatitis. Prolonged contact of acid leads to visual damage to vision loss. If swallowed, may cause burns to the mucous membranes of the mouth and digestive system.

Environmental Effects:

 Affects rivers and streams by changing the pH of the water. May contaminate the soil. Vapors may temporarily affect air quality.

Physical and chemical hazards:

 Reacts with metals such as; iron, aluminum, zinc, magnesium, among others, forming hydrogen, which mixed with air may cause explosion and air displacement upon ignition under specific.

4 0

4 years ago

Two students are given different samples of a substance and are instructed to determine the properties of the substance.

Hunter-Best [27]

The complete question is given below:

Two students are given different samples of a substance and are instructed to determine the properties of the substance.

Which statement describes a property that will be the same for both students?

A. color because it is an extensive property

B. mass because it is an extensive property

C. boiling point because it is an intensive property

D. volume because it is an intensive property .

ANSWER

The correct option is C.

The physical properties of substances are divided into two, intensive and extensive properties.

Intensive properties refers to those features of a substance that do not depend on the quantity of the material that is available. Whether the sample available is big or small, the intensive properties remain the same. Examples of intensive properties are: melting point, boiling point, refractive index, hardness, density color, etc. This question is asking us to look for an intensive property.

Extensive properties refers to those characteristics of a substance that depend on the amount of substance present. Examples of these properties are: mass, volume, size, weight, length, etc.

From the options given, option A is wrong because color is not an extensive property, it is intensive. Option B is wrong because the mass depend on the amount of sample given and the same thing apply to option D.

The correct option is C, because no matter the quantity of that substance that you have, the boiling point will always remains the same.

6 0

4 years ago

iron is made by a reduction of iron oxide with carbon monoxide. Fe2O3+3CO-2Fe+3CO2. Calculate the mass of iron that can be forme

lyudmila [28]

Answer:

Mass = 88.12 g

Explanation:

Given data:

Mass of iron oxide = 126 g

Mass of iron formed = ?

Solution:

Chemical equation:

Fe₂O₃ + 3CO → 2Fe + 3CO₂

Number of moles of iron oxide:

Number of moles = mass/molar mass

Number of moles = 126 g/ 159.69 g/mol

Number of moles = 0.789 mol

Now we will compare the moles of iron with iron oxide.

Fe₂O₃ : Fe

1 : 2

0.789 : 2/1×0.789 = 1.578 mol

Mass of iron:

Mass = number of moles ×molar mass

Mass = 1.578 mol × 55.84 g/mol

Mass = 88.12 g

4 0

3 years ago