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2 years ago

All of the elements in the actinide family are ? (liquids/radioactive).

Chemistry

2 answers:

Colt1911 [192]2 years ago

4 0

Answer:

c-Radioactive

Explanation:

Aleksandr [31]2 years ago

3 0

Answer:

Radioactive

Explanation:

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Given that ΔH = −571.6 kJ/mol for the reaction 2 H2(g) + O2(g) → 2 H2O(l), calculate ΔH for these reactions. (a) 2 H2O(l) → 2 H2

pashok25 [27]

Answer : The value of $\Delta H$ for the reaction is +571.6 kJ/mole.

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction is,

$2H_2(g)+O_2(g)\rightarrow 2H_2O(l)$ $\Delta H_1=-571.6kJ/mole$

Now we have to determine the value of $\Delta H$ for the following reaction i.e,

$2H_2O(l)\rightarrow 2H_2(g)+O_2(g)$ $\Delta H_2=?$

According to the Hess’s law, if we reverse the reaction then the sign of $\Delta H$ change.

So, the value $\Delta H_2$ for the reaction will be:

$\Delta H_2=-(-571.6kJ/mole)$

$\Delta H_2=+571.6kJ/mole$

Hence, the value of $\Delta H$ for the reaction is +571.6 kJ/mole.

6 0

2 years ago

A chemist must prepare 300.0mL of nitric acid solution with a pH of 0.70 at 25°C. He will do this in three steps: Fill a 300.0mL

d1i1m1o1n [39]

Answer: The volume of concentrated solution required is 9.95 mL

Explanation:

To calculate the pH of the solution, we use the equation:

$pH=-\log[H^+]$

We are given:

pH = 0.70

Putting values in above equation, we get:

$0.70=-\log[H^+]$

$[H^+]=10^{-0.70}=0.199M$

1 mole of nitric acid produces 1 mole of hydrogen ions and 1 mole of nitrate ions.

Molarity of nitric acid = 0.199 M

To calculate the volume of the concentrated solution, we use the equation:

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated nitric acid solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted nitric acid solution

We are given:

$M_1=7.0M\\V_1=?mL\\M_2=0.199M\\V_2=350mL$

Putting values in above equation, we get:

$7.0\times V_1=0.199\times 350.0\\\\V_1=\frac{0.199\times 350}{7.0}=9.95mL$

Hence, the volume of concentrated solution required is 9.95 mL

6 0

2 years ago

What are the metalloids on the periodic table?

Sauron [17]

The metalloids; boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po) and astatine (At) are the elements found along the step like line between metals and non-metals of the periodic table.

5 0

2 years ago

A chemist determined by measurements that 0.050 moles of aluminum participated in a chemical reaction. Calculate the mass of alu

Law Incorporation [45]

Answer:

13.5 g

Explanation:

This question is solved easily if we remember that the number of moles is obtained by dividing the mass into the atomic weight or molar mass depending if we are referring to elements or molecules.

Therefore, the mass of aluminum in the reaction will the 0.050 mol Al times the atomic weight of aluminum.

number of moles = n = mass of Al / Atomic Weight Al

⇒ mass Al = n x Atomic Weight Al = 0.050 mol x 27 g mol⁻¹

= 13.5 g

We have three significant figures in 0.050 and therefore we should have three significant figures in our answer.

8 0

3 years ago

Describe the electron sharing between 2 oxygen atoms

erastova [34]

When two oxygen atoms get close to each other, the attractions from the nucleus of both atoms attract the outer electrons.

(BRAINLIEST PLEASE!!!)

3 0

2 years ago