About how many elements are found on the periodic table? Question 8 options:

Chemistry

1 answer:

krek1111 [17]3 years ago

3 0

the answer is actually 118 look it up

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Magnesium sulfate heptahydrate is heated until all the water is driven off. The sample loses 11.80 grams upon heating. What was

iren [92.7K]

Hello!

The initial mass of Magnesium Sulfate Heptahydrate (MgSO₄·7H₂O) is 23,08 g

The chemical reaction for the dehydrating of Magnesium Sulfate Heptahydrate (MgSO₄·7H₂O) is the following:

MgSO₄·7H₂O(s) + Δ → MgSO₄(s) + 7H₂O(g)

We know that the sample loses 11,80 g upon heating. That mass is the mass of Water that is released as vapor. Knowing that piece of information, we can apply the following conversion factor to go from the mass of water to the moles of water and back to the mass of the original compound (mi).

$mi=11,80gH_2O* \frac{1 mol H_2O}{18gH_2O}* \frac{1molMgSO_4.7H_2O}{7molH_2O}* \frac{246,47 g MgSO_4.7H_2O}{1 mol MgSO_4.7H_2O} \\ \\ mi=23,08gMgSO_4.7H_2O$

Have a nice day!

6 0

3 years ago

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

Lerok [7]

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.

3 0

3 years ago

Read 2 more answers

Find the number of moles of water that can be formed if you have 182 mol of hydrogen gas and 86 mol of oxygen gas.

frutty [35]

Water has a chemical formula of H2O. This means that for every 2 moles of hydrogen and 1 mole of oxygen, one mole of water will be formed.

Note that hydrogen gas and oxygen gas are both biatomic molecules.

(1) (182 mol H2) x (1 mol H2O/ 1 mol H2) = 182 mol H2O
(2) (86 mol O2) x (2 mol H2O / 1 mol O2) = 172 mol H2O

We choose the smaller number of the two as the answer to this item. Thus, the answer to this question is 172 mol of H2O can be formed out of the given quantities.

3 0

3 years ago

Which is the correct Lewis structure for carbon monoxide?

LuckyWell [14K]

<span>The Lewis structure for CO has 10 valence electrons. For the CO Lewis structure you'll need a triple bond between the Carbon and Oxygen atoms in order to satisfy the octets of each atom while still using the 10 valence electrons available for the CO molecule.</span>

7 0

3 years ago

The moon makes light the same way that the sun does.True or False

lesya [120]

Answer: false

Explanation:

7 0

3 years ago