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3 years ago

5

What it is the total length of two pieces of rubber tubing which are 7.69 cm and 4.028 cm in length? Express this answer to the

correct number of significant figures

1 answer:

Brilliant_brown [7]3 years ago

6 0

The corrects answer it 9. 45

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A 0.6467-g portion of manganese dioxide was added to an acidic solution in which 1.1701 g of a chloride-containing sample was di

Katen [24]

Answer:

29.39% of AlCl₃ in the sample

Explanation:

Based on the reaction:

MnO₂(s) + 2Cl⁻ + 4H⁺ → Mn²⁺ + Cl₂(g) + 2H₂O

We can find the amount of chloride in solution with the amount of MnO₂ that reacted as follows:

<em>Initial mass MnO₂ = 0.6467g</em>

<em>Recovered mass = 0.3104g</em>

Mass that reacted = 0.6467g - 0.3104g = 0.3363g

<em>Moles MnO₂ -Molar mass: 86.9368g/mol-:</em>

0.3363g * (1mol / 86.9368g) = 3.868x10⁻³ moles MnO₂

<em>Moles Cl⁻:</em>

3.868x10⁻³ moles MnO₂ * (2mol Cl⁻ / 1mol MnO₂) = 7.737x10⁻³ moles Cl⁻

<em>Moles of AlCl₃ and mass -Molar mass AlCl₃: 133.34g/mol-:</em>

7.737x10⁻³ moles Cl⁻ * (1mol AlCl₃ / 3mol Cl⁻) = 2.579x10⁻³ moles AlCl₃

2.579x10⁻³ moles AlCl₃ * (133.34g / mol) =

<em>0.3439g of AlCl₃</em> are present in the sample.

The percent is:

0.3439g of AlCl₃ / 1.1701g * 100 =

<h3>29.39% of AlCl₃ in the sample</h3>

7 0

3 years ago

DUE IN 30 MINUTES!!! (please keep it short if you can, if not its ok.) What is the molar mass of Pb(SO4)2? Explain how you calcu

kipiarov [429]

Answer:

399

Explanation:

Pb(SO4)2 contains 1 atom of Pb, 2 atoms of S and 8 atoms of O. So, atomic mass of Pb(SO4)2 is 207 + 64 + 128 = 399 u. Therefore, molar mass of Pb(SO4)2 is 399 g/mol.HOPE THIS helps. Good Luck

5 0

3 years ago

Read 2 more answers

What is an atom that has the same number of protons as other atoms of the same element, but has a different number of neutrons?

PSYCHO15rus [73]

Answer:

isotopes

Atoms with the same number of protons but different numbers of neutrons are called isotopes. Because the number of neutrons can vary for a given element, the mass numbers of different atoms of an element may also vary. For example, some helium atoms have three neutrons instead of two (these are called isotopes and are discussed in detail later on)

Explanation:

4 0

3 years ago

A solution of NaCl ( aq ) is added slowly to a solution of lead nitrate, Pb ( NO 3 ) 2 ( aq ) , until no further precipitation o

statuscvo [17]

Answer : The molarity of $Pb(NO_3)_2$ solution is, 0.352 M

Explanation :

First we have to calculate the moles of $PbCl_2$

$\text{Moles of }PbCl_2=\frac{\text{Given mass }PbCl_2}{\text{Molar mass }PbCl_2}$

Molar mass of $PbCl_2$ = 278.1 g/mol

$\text{Moles of }PbCl_2=\frac{19.58g}{278.1g/mol}=0.07041mol$

Now we have to calculate the moles of $CaCl_2$

The balanced chemical equation is:

$Pb(NO_3)_2(aq)+2NaCl(aq)\rightarrow PbCl_2(s)+2NaNO_3(aq)$

From the balanced reaction we conclude that

As, 1 mole of $PbCl_2$ produced from 1 mole of $Pb(NO_3)_2$

So, 0.07041 mole of $PbCl_2$ produced from 0.07041 mole of $Pb(NO_3)_2$

Now we have to calculate the molarity of $Pb(NO_3)_2$

$\text{Molarity of }Pb(NO_3)_2=\frac{\text{Moles of }Pb(NO_3)_2}{\text{Volume of solution in (L)}}$

$\text{Molarity of }Pb(NO_3)_2=\frac{0.07041mol}{0.200L}=0.352M$

Therefore, the molarity of $Pb(NO_3)_2$ solution is, 0.352 M

4 0

3 years ago

FIRST GETS BRAINLIEST

lisov135 [29]

Answer:

0.07172 L = 7.172 mL.

Explanation:

We can use the general law of ideal gas: <em>PV = nRT. </em>

where, P is the pressure of the gas in atm (P = 1.0 atm, Standard P).

V is the volume of the gas in L (V = ??? L).

n is the no. of moles of the gas in mol (n = 3.2 x 10⁻³ mol).

R is the general gas constant (R = 0.0821 L.atm/mol.K),

T is the temperature of the gas in K (T = 273 K, Standard T).

<em>∴ V = nRT/P =</em> (3.2 x 10⁻³ mol)(0.0821 L.atm/mol.K)(273 K)/(1.0 atm) = <em>0.07172 L = 7.172 mL.</em>

8 0

3 years ago