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Tju [1.3M]
3 years ago
7

A chemist who studies water samples did a demonstration of how to test for lead in water. She added a clear solution of potassiu

m iodide to a clear solution of lead nitrate. Then a yellow swirling solid formed in the liquid. What is most likely true about the yellow solid?
Chemistry
2 answers:
evablogger [386]3 years ago
8 0

<em>I actually need help myself with question and no one has helped me yet ? </em>

Lerok [7]3 years ago
3 0

Answer:

The swirling yellow solid formed is lead iodide (PbI₂).

Explanation:

  • The reaction of potassium iodide (KI) with lead nitrate (Pb(NO₃)₂) will produce lead iodide (PbI₂) and potassium nitrate (KNO₃) according to the equation:

2KI + Pb(NO₃)₂ → PbI₂↓ + 2KNO₃

  • Lead iodide (PbI₂) is a yellow swirling precipitate that is formed from the reaction.
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Sodium metal reacts with water to produce hydrogen gas.
Darina [25.2K]

Answer:

Explanation:

Question 6 options:

1)

A single replacement reaction takes place because sodium is less reactive than hydroxide ions.

7 0
2 years ago
How many liters of oxygen gas, at standard
Karo-lina-s [1.5K]

Answer:

Explanation:

  • For the balanced reaction:

<em>4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)​.</em>

It is clear that 4 mol of Fe react with 3 mol of O₂ to produce 2 mol of Fe₂O₃.

  • Firstly, we need to calculate the no. of moles of 35.8 grams of Fe metal:

no. of moles of Fe = mass/molar mass = (35.8 g)/(55.845 g/mol) = 0.64 mol.

  • Now, we can find the no. of moles of O₂ is needed to react with the proposed amount of Fe:

<em><u>Using cross multiplication:</u></em>

4 mol of Fe is needed to react with → 3 mol of O₂, from stichiometry.

0.64 mol of Fe is needed to react with → ??? mol of O₂.

∴ The no. of moles of O₂ needed = (3 mol)(0.64 mol)/(4 mol) = 0.48 mol.

  • Finally, we can get the volume of oxygen using the information:

<em>It is known that 1 mole of any gas occupies 22.4 L at standard P and T (STP).</em>

<em></em>

<em><u>Using cross multiplication:</u></em>

1 mol of O₂ occupies → 22.4 L, at STP conditions.

0.48 mol of O₂ occupies → ??? L.

∴ The no. of liters of O₂ = (0.48 mol)(22.4 L)/(1 mol) = 10.752 L.

5 0
3 years ago
Find the percent composition of C7H5N3O6
Oksana_A [137]

Finding percent composition is fairly easy. You only need to divide the mass of an element by the total mass of the compound. We can do this one element at a time.

First, let's find the total mass by using the masses of the elements given on the periodic table.

7 x 12.011 (mass of Carbon) = 84.077

5 x 1.008 (mass of Hydrogen) = 5.04

3 x 14.007 (mass of Nitrogen) = 42.021

6 x 15.999 (mass of Oxygen) = 95.994

Add all of those pieces together.

84.077 + 5.04 + 42.021 + 95.994 = 227.132 g/mol is your total. Since we also just found the mass of each individual element, the next step will be very easy.

Carbon: 84.077 / 227.132 = 0.37016 ≈ 37.01 %

Hydrogen: 5.04 / 227.132 = 0.022189 ≈ 2.22 %

Nitrogen: 42.021 / 227.132 = 0.185 ≈ 18.5 %

Oxygen: 95.994 / 227.132 = 0.42263 ≈ 42.26 %

You can check your work by making sure they add up to 100%. The ones I just found add up to 99.99, which is close enough. A small difference (no more than 0.03 in my experience) is just a matter of where you rounded your numbers.

5 0
2 years ago
Which probe should be used to check the temperature of a chicken breast?
Eddi Din [679]

Answer:

penetration probe

Explanation:

it is a penetration probe

8 0
2 years ago
Table salt is a refined salt containing about 97 to 99% sodium Chloride iodized salt containing potassium iodide is widely avail
Free_Kalibri [48]

Answer:

Explanation:

Sodium chloride is ionic compound. It is formed by the transfer of electron from one atom to the atom of another element.  

Both bonded atoms have very large electronegativity difference. The atom with large electronegativity value accept the electron from other with smaller value of electronegativity.

The electronegativity of chlorine is 3.16 and for sodium is 0.93. There is large difference is present. That's why electron from sodium is transfer to the chlorine. Sodium becomes positive and chlorine becomes negative ion. Both atoms are bonded together electrostatic attraction occur between anion and cations.

Sodium atom have one valance electron by losing this one valance electron sodium atom get the complete octet. Chlorine atom has seven valance electrons and needed to lose seven valance electrons or to get one electron and thus complete the octet. It is very easy for chlorine atom to get one electrons instead of losing all seven electron. Thus when it react with sodium it gain the valance electron of sodium and form ionic compound.

That's why only one atom of  sodium combine with one atom chlorine.

8 0
3 years ago
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