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MAVERICK [17]
3 years ago
12

28Which is true?

Chemistry
1 answer:
sergij07 [2.7K]3 years ago
8 0
28) All elements are made of atoms

29)Protons and Neutrons
-Electrons make up the outside of the Nucleus
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The mass % of Ca in CaSO4 is 29.45%. To calculate the mass of Ca present in a 25.6-g sample of this compound, the correct proced
Rufina [12.5K]

Answer:

The correct answer is - 29.45 / 100 x 25.6 = 7.5392 grams

Explanation:

It is given in the question that in 100 gms of CaSO4 there are 29.45 grams of Ca present and there is 25.6 gram of total CaSO4 sample present, So, to calculate the exact value of calcium in this given sample is:

mass of Ca = total amount of sample*percentage of calcium in sample /100

M of Ca =25.6*29.45/100

M of Ca = 7.5392 grams

Thus, the correct procedure is given by 29.45 / 100 x 25.6 = 7.5392 grams

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2 years ago
What is the balance equation for HgO(s)- Hg(l)+O2(g)
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The balanced equation is   2HgO --> 2Hg + O2
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3 years ago
The molar mass of sucrose (C12H22O11) is 342.3 g/mol. A chemist has a 0.500-mol sample of sucrose. What is the mass, in grams, o
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171 is the answer that I got after my calculations.
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What happens to polyester slacks if aqueous naoh is spilled on them? What happens to polyester slacks if aqueous is spilled on t
Helga [31]

Polyester is a condensation polymer of dicarboxylic acid and diol. Example : Polethylene terphthalate is polymer of ethylene glycol and tere phthallic acid. When a strong acid like HCl or a strong base like NaOH comes in contact with polyester (like spilled on slacks) it causes hydrolysis of polyester and it get converted back to dicarboxylic and diol(the monomers). the general reaction will be RCOOR' ---> RCOOH + R'OH Thus slacks will get teared.

3 0
3 years ago
10g of hyrogen react with excess of oxygen gas according to the equation:
Degger [83]

Answer:

Volume of O₂ = 56 dm³

mass of water vapors (H₂O) = 90 g

Explanation:

Data Given:

mass of Oxygen = 10 g

Volume of Oxygen = ?

mass of the water vapor = ?

Reaction Given:

                 2H₂+O₂---->2H₂O

Solution:

First we have to look at the reaction for the information required

                 2H₂   +  O₂  -------> 2H₂O

               2 mol    1mol           2 mol

now convert moles to grams

molar mass of H₂ = 2(1) = 2 g/mol

molar mass of O₂ = 2(16) = 32 g/mol

molar mass of H₂0 = 2(1) + 16 = 18 g/mol

So the masses will be

                      2H₂          +              O₂        ------->      2H₂O

                2 mol (2 g/mol)      1mol (32 g/mol)         2 mol (18 g/mol)

                      4 g                            32 g                           36 g

So now we know that

4 g of hydrogen combine with 32 g of Oxygen and give 36 g of water vapors.

By using above information

First we find the volume of Oxygen:

For this first we find mass and then moles of Oxygen

As we know

if 4 g of hydrogen combine with 32 g of Oxygen then how much oxygen will react with 10 g of hydrogen

Apply unity formula

                        4 g of hydrogen H₂ ≅ 32 g of Oxygen O₂

                         10 g of hydrogen H₂ ≅ X g of Oxygen O₂    

by doing Cross multiplication

                         g of Oxygen O₂   = 32 g x 10 g / 4 g

                         g of Oxygen O₂   = 80 g

So,                  

mass of oxygen = 80 g

now find moles of oxygen

formula used:

            no. of moles = mass in grams/ molar mass . . . . . . (1)

Put values in above equation 1

            no. of moles = 80 g / 32 g/mol

             no. of moles = 2.5

Now to find volume of oxygen

Formula used

 Volume of O₂ = no. of moles x molar volume (22.4 dm³/ mol) . . . . . . (2)

Put values in equation 2

             Volume of O₂ = 2.5 moles x 22.4 dm³/mol

            Volume of O₂ = 56 dm³

______________________

Now to find mass of water vapors

As we now

if 4 g of hydrogen produce 36 g of water vapors then how much water vapor will produce from 10 g of hydrogen

Apply unity formula

                        4 g of hydrogen H₂ ≅ 36 g of water vapors (H₂O)

                         10 g of hydrogen H₂ ≅ X g of water vapors (H₂O)  

by doing Cross multiplication

                         g of water vapors (H₂O) = 36 g x 10 g / 4 g

                         g of water vapors (H₂O)   = 90 g

So,                  

mass of water vapors (H₂O) = 90 g

5 0
3 years ago
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