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3 years ago

Which element's properties form the basis for all life?

Chemistry

1 answer:

PilotLPTM [1.2K]3 years ago

4 0

Answer:

carbon

Explanation:

The properties of carbon forms the basis for all life. Explanation: The atoms of carbon are found in the molecules of all living species.

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Enter the net ionic equation for the reaction between HCHO2 (a weak acid) and NaOH.

olchik [2.2K]

Answer:

Answer in image below.

5 0

2 years ago

250.0 mL of 0.250 M calcium chloride is mixed with 440.0 mL of 0.155 M sodium hydroxide and a precipitation reaction occurs. Wha

Vladimir [108]

Answer:

Solid: 2.52 g

Concentrations: [CaCl₂] = 0.041 M, [NaCl] = 0.100 M

Explanation:

When calcium chloride (CaCl₂) reacts with sodium hydroxide (NaOH), a double replacement reaction occurs, forming NaCl and Ca(OH)₂. NaCl is a soluble salt, and Ca(OH)₂ is a little soluble base, thus, Ca(OH)₂ will be the precipiate.

The balanced reaction equation is:

CaCl₂(aq) + 2NaOH(aq) → 2NaCl(aq) + Ca(OH)₂(s)

The number of moles of the reactants mixed are their volume multiplied by their concentration:

nCaCl₂ = 0.250 L * 0.25 mol/L = 0.0625 mol

nNaOH = 0.440 L*0.155 mol/L = 0.0682 mol

One of the reactants is limiting, and the other is in excess. Let's suppose that CaCl₂ is limiting, then, by the stoichiometry:

1 mol of CaCl₂ ------------- 2 moles of NaOH

0.0625 mol ------------ x

By a simple direct three rule:

x = 0.125 mol of NaOH

Because there's less NaOH than the value found, NaOH must be the limiting reactant and CaCl₂ is in excess. Thus, by the stoichiometry:

1 mol of CaCl₂ ------------- 2 moles of NaOH

x ------------- 0.0682 mol

By a simple direct three rule:

2x = 0.0682

x = 0.0341 mol of CaCl₂ reacts

The number of moles of CaCl₂ that remains is: 0.0625 - 0.0341 = 0.0284 mol. The final volume is 250.0 mL + 440.0 mL = 690. mL = 0.69 L

[CaCl₂] = 0.0284/0.69 = 0.041 M

For the solube product:

2 moles of NaOH ------------ 2 moles of NaCl

0.0682 mol ------------ x

x = 0.0682 mol of NaCl formed

[NaCl] = 0.0682/0.69 = 0.100 M

For the precipitate:

2 moles of NaOH ----------- 1 mol of Ca(OH)₂

0.0682 mol ---------- x

x = 0.0341 mol of Ca(OH)₂ formed

The molar of Ca(OH)₂ is 74.0 g/mol, and the mass is the number of moles multiplied by the molar mass:

mCa(OH)₂ = 0.0341*74 = 2.52 g

8 0

3 years ago

You have 16.0 g of some compound and you perform an experiment to remove all of the oxygen, 11.2 g of iron is left. What is the

oksian1 [2.3K]

The empirical formula of this compound is equal to $Fe_{2}O_3$ .

<h3>Empirical formula</h3>

To calculate the empirical formula of a compound, it is necessary to know the number of moles present.

Therefore, we will use the molar mass of iron and oxygen to find the amount of moles, so that:

$MM_O = 16g/mol\\MM_Fe = 55.8g/mol$

$MM = \frac{m}{mol}$

Oxygen

$16 = \frac{4.8}{mol}$

$mol = 0.3$

Iron

$55.8 = \frac{11.2}{mol}$

$mol = 0.2$

Finally, as the empirical formula is composed of integers numbers of moles, just multiply the values by the smallest common factor to transform into an integer, so that:

O => $0.3 \times 10 = 3moles$

Fe => $0.2 \times 10 = 2moles$

So, the empirical formula of this compound is equal to $Fe_{2}O_3$

Learn more about empirical formula in: brainly.com/question/1363167

6 0

3 years ago

Fluorine gas a 300 K occupies a volume of 500 mL. To what temperature should it be lowered to bring the volume to 300 mL?

snow_tiger [21]

180 K

V1/T1 = V2/T2
V1 = 500 mL
T1 = 300 K
V2 = 300 mL

Solve the equation for T2 —> T2 = V2T1/V1

T2 = (300 mL)(300 K) / (500 mL) = 180 K

6 0

3 years ago

Which of the following reactions shows that the formation of CO2 releases

tiny-mole [99]

Answer:

A. C(s) + O2(g) → CO2(g) + 393.5 kJ

Explanation:

The formation of carbon IV oxide (CO2) is an exothermic process. n exothermic process is a chemical process in which heat is evolved. Speaking in lay man's terminology, heat is one of the 'products' of the reaction. This implies that heat is evolved by the process.

The formation of CO2 is always a combustion reaction where heat is evolved or released by the reaction system. Hence the reaction could be shown as;

C(s) + O2(g) → CO2(g) + 393.5 kJ

This implies that 393.5 kJ of energy is released in the reaction in the form of heat. Hence the answer given in the answer box.

7 0

3 years ago