Which of the following tends to form anions when bonding with other elements?

Derek needs a tool that delivers 25.00 mL of a sodium hydroxide solution. What tool would be best for him to use?

3241004551 [841]

He may use a pipette with a volume greater than 25 ml to transfer the solution.

4 0

3 years ago

What is the radius of a hydrogen atom whose electron is bound by 0.544 ev? express your answer with the appropriate units?

insens350 [35]

First, we need to calculate the principal quantum number n for this electron, using the equation:
E = (-13.60 eV) / (n x n)
where E is the energy that is used to bound the electron (here, E = - 0.544 eV).
- 0.544 eV = (-13.60 eV) / (n x n)
n x n = (- 13.60 eV) / (- 0.544 eV)
n x n = 25
n = 5

The orbital radius that is equal to the radius of a hydrogen atom is calculated using the equation:
r = 0.053 nm x n x n
r = 0.053 nm x 5 x 5
r = 0.053 nm x 25
r = 1.325 nm

6 0

2 years ago

One reaction involved in the conversion of iron ore to the metal is FeO(s) + CO(g) → Fe(s) + CO2(g) Use Hess’s Law to calculate

Ugo [173]

Answer:

$\delta H_{rxn} = -66.0 \ kJ/mole$

Explanation:

Given that:

$3FeO_3_{(s)}+CO_{(g)} \to 2Fe_3O_4_{(s)} +CO_{2(g)} \ \ \delta H = -47.0 \ kJ/mole -- equation (1) \\ \\ \\ Fe_2O_3_{(s)} +3CO_{(g)} \to 2FE_{(s)} + 3CO_{2(g)} \ \ \delta H = -25.0 \ kJ/mole -- equation (2) \\ \\ \\ Fe_3O_4_{(s)} + CO_{(g)} \to 3FeO_{(s)} + CO_{2(g)} \ \delta H = 19.0 \ kJ/mole -- equation (3)$

From equation (3) , multiplying (-1) with equation (3) and interchanging reactant with the product side; we have:

$3FeO_{(s)} + CO_{2(g)} \to Fe_3O_4_{(s)} + CO_{(g)} \ \delta H = -19.0 \ kJ/mole -- equation (4)$

Multiplying (2) with equation (4) ; we have:

$6FeO_{(s)} + 2CO_{2(g)} \to 2Fe_3O_4_{(s)} + 2CO_{(g)} \ \delta H = -38.0 \ kJ/mole -- equation (5)$

From equation (1) ; multiplying (-1) with equation (1); we have:

$2Fe_3O_4_{(s)} +CO_{2(g)} \to 3FeO_3_{(s)}+CO_{(g)} \ \ \delta H = 47.0 \ kJ/mole -- equation (6)$

From equation (2); multiplying (3) with equation (2); we have:

$3 Fe_2O_3_{(s)} +9CO_{(g)} \to 6FE_{(s)} + 9CO_{2(g)} \ \ \delta H = -75.0 \ kJ/mole -- equation (7)$

Now; Adding up equation (5), (6) & (7) ; we get:

$6FeO_{(s)} + 2CO_{2(g)} \to 2Fe_3O_4_{(s)} + 2CO_{(g)} \ \delta H = -38.0 \ kJ/mole -- equation (5)$

$2Fe_3O_4_{(s)} +CO_{2(g)} \to 3FeO_3_{(s)}+CO_{(g)} \ \ \delta H = 47.0 \ kJ/mole -- equation (6)$

$3 Fe_2O_3_{(s)} +9CO_{(g)} \to 6FE_{(s)} + 9CO_{2(g)} \ \ \delta H = -75.0 \ kJ/mole -- equation (7)$

$FeO \ \ \ + \ \ \ CO \ \ \to \ \ \ \ Fe_{(s)} + \ \ CO_{2(g)} \ \ \ \delta H = - 66.0 \ kJ/mole$

$\delta H_{rxn} = \delta H_1 + \delta H_2 + \delta H_3$ (According to Hess Law)

$\delta H_{rxn} = (-38.0 + 47.0 + (-75.0)) \ kJ/mole$

$\delta H_{rxn} = -66.0 \ kJ/mole$

8 0

2 years ago

A student places a 12-gram cube of ice inside a container. After six hours, the student returns to observe the contents of the c

jok3333 [9.3K]

Answer:

The answer is c

Explanation:

Because all of the Other ones did not make sense

7 0

2 years ago

Two elements next to each other that have decreasing atomic masses

pogonyaev

Answer:

Tellurium (Te) and iodine (I) are two elements next to each other that have decreasing atomic masses.

Explanation:

The atomic mass of tellurium (Te) is 127.60 g/mol and the atomic mass of iodine (I) is 126.904 g/mol; so, in spite of iodine being to the right of tellurium in the periodic table (because the atomic number of iodine is bigger than the atomic number of tellurium), the atomic mass of iodine is less than the atomic mass of tellurium.

The elements are arranged in increasing order of atomic number in the periodic table.

The atomic number is equal to the number of protons and the mass number is the sum of the protons and neutrons.

The mass number, except for the mass defect, represents the atomic mass of a particular isotope. But the atomic mass of an element is the weighted average of the atomic masses of the different natural isotopes of the element.

Normally, as the atomic number increases, you find that the atomic mass increases, so most of the elements in the periodic table, which as said are arranged in icreasing atomic number order, match with increasing atomic masses. But the relative isotope abundaces of the elements can change that.

It is the case that the most common isotopes of tellurium have atomic masses 128 amu and 130 amu, whilst most common isotopes of iodine have an atomic mass 127 amu. As result, tellurium has an average atomic mass of 127.60 g/mol whilst iodine has an average atomic mass of 126.904 g/mol.

5 0

2 years ago