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Masteriza [31]
3 years ago
8

1.) How many periods are on the periodic table? Are periods the columns or the rows on the periodic table?

Chemistry
2 answers:
RideAnS [48]3 years ago
8 0
The periods are the rows, and there are 8 of them (I think)
mariarad [96]3 years ago
4 0

There are 8 periods. The periods are the rows.

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A 36.0−g sample of an unknown metal at 99°C was placed in a constant-pressure calorimeter containing 70.0 g of water at 24.0°C.
Dimas [21]

Answer: 0.52849 j /g °C

Explanation:

Given the following :

Mass of metal = 36g

Δ Temperature of metal = (28.4 - 99)°C = - 70.6°C

Mass of water = 70g

Δ in temperature of water = (28.4 - 24.0) = 4.4°C

Heat lost by metal = (heat gained by water + heat gained by calorimeter)

Quantity of heat(q) = mcΔT

Where; m = mass of object ; c = specific heat capacity of object

Heat lost by metal:

- (36 × c × - 70.6) = 2541.6c - - - - (1)

Heta gained by water and calorimeter :

(70 × 4.184 × 4.4) + (12.4 × 4.4) = 1288.672 + 54.56 = 1343.232 - - - - (2)

Equating (1) and (2)

2541.6c = 1343.232

c = 1343.232 / 2541.6

c = 0.52849 j /g °C

8 0
3 years ago
Consider the following reaction between calcium oxide and carbon dioxide: CaO(s)+CO2(g)→CaCO3(s) A chemist allows 14.4 g of CaO
sweet-ann [11.9K]

Answer:

Theoretical yield =26.03 g

Percent yield = 87%

Limiting reactant = CaO

Explanation:

Given data:

Mass of CaO = 14.4 g

Mass of CO₂ = 13.8 g

Actual yield of CaCO₃ = 22.6 g

Theoretical yield = ?

Percent yield = ?

Limiting reactant = ?

Solution:

Chemical equation:

CaO + CO₂   → CaCO₃

Number of moles of CaO:

Number of moles  = Mass /molar mass

Number of moles = 14.4 g / 56.1 g/mol

Number of moles  = 0.26 mol

Number of moles of CO₂:

Number of moles = Mass /molar mass

Number of moles = 13.8 g / 44 g/mol

Number of moles = 0.31 mol

Now we will compare the moles of CO₂ and CaO with CaCO₃ .

                  CO₂         :                CaCO₃  

                  1               :                 1

                 0.31           :              0.31

                CaO           :               CaCO₃  

                 1                :                 1

                 0.26         :              0.26

The number of moles of  CaCO₃ produced by CaO are less it will be limiting reactant.

Mass of CaCO₃: Theoretical yield

Mass of CaCO₃ = moles × molar mass

Mass of CaCO₃ =0.26 mol × 100.1 g/mol

Mass of CaCO₃ =  26.03 g

Percent yield:

Percent yield = actual yield / theoretical yield × 100

Percent yield = 22.6 g/ 26.03 g × 100

Percent yield = 0.87× 100

Percent yield = 87%

Limiting reactant:

The number of moles of  CaCO₃ produced by CaO are less it will be limiting reactant.

7 0
3 years ago
For each value of the principal quantum number n, what are the possible values of the electron spin quantum number?
Ede4ka [16]

Answer:

The values for spin quantum number +1/2 and - 1/2

Explanation:

Principal quantum number denoted by (n) is used to describe the shell or orbits that electrons are found. Principal quantum number can assume a value of n= 1,2, 3, 4,5............ which indicates K, L, M, N, O shell respectively.

To know the maximum number of electrons in each shell, the formula (2n²) can be used. The letter 'n' denotes the values of principal quantum number 1,2,3,4

For example

  • n=1 (K shell) has maximum number of 2 electrons
  • n=2 (L shell) has the maximum number of 8 electrons
  • n=3 (M shell) has the maximum number of 18 electrons
  • n=4 (N shell) has the maximum number of 32 electrons

All the electron in each shell will have a spin quantum number of +1/2 and - 1/2. One electron in each degenerate orbital will spin up (+1/2) while the other electron will spin down (-1/2).

7 0
3 years ago
What are the reaction types for the following?
Bingel [31]

Answer:

1. decomposition

2. combustion

3.single replacement

4. combination

5. double replacement

Explanation:

1. one compound is split into 2 elements

2. co2 and h20 was the product of the reaction

3. cu is replaced with co

4. 2 compounds become one compound

5. ca is replaced with na and na is replaced with ca

6 0
3 years ago
Which of the following elements is a nonmetal? a. selenium (Se) b. yttrium (Y) c. barium (Ba) d. calcium (Ca) e. All of these ar
san4es73 [151]

<u>Answer:</u>

The correct answer option is a. Selenium (Se).

<u>Explanation:</u>

From the given answer options, Selenium (Se) is the only element which is a non metal.

It has the atomic number 34 with atomic weight 78.96. It is a member of the sulfur group of the non metallic elements and falls in period 4 of the Periodic table.

Selenium has non metallic properties which are intermediate between the elements that lie above and below it in the Periodic table.

3 0
3 years ago
Read 2 more answers
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