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Alex73 [517]
3 years ago
15

Need help with 7,9 and may you check my answer for 8 to ?

Chemistry
2 answers:
fomenos3 years ago
8 0
8 looks right to me but not 100%
steposvetlana [31]3 years ago
7 0
Number 9 is C because they are the same element but different numbers. Number 8 is B because they are isotopes of each other, and isotopes have varying number of protons (that’s what make them isotopes of each other.) Number 7 is B.
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Round 23.455 cm into 4 significant figures
seraphim [82]
It would be 23.46, since the next number is a 5 so we can round up.

Significant figures are:
ANY number that is not 0
Any 0 between two nonzero digits
Any 0 following a decimal (i.e 1.50)
4 0
3 years ago
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Which of the following compounds has the general formula X3Y2?Which of the following compounds has the general formula X3Y2?
prisoha [69]

There are no above options to choose from so I am giving an example of a X3Y2 formula which is Magnesium nitride, the formula is Mg3N2.

6 0
2 years ago
*PLEASE HELP ASAP*
sveticcg [70]
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7 0
3 years ago
A compound is found to be 30.45% n and 69.55 % o by mass. if 1.63 g of this compound occupy 389 ml at 0.00°c and 775 mm hg, what
Charra [1.4K]
1) mass composition

N: 30.45%
O: 69.55%
   -----------
   100.00%

2) molar composition

Divide each element by its atomic mass

N: 30.45 / 14.00 = 2.175 mol

O: 69.55 / 16.00 = 4.346875

4) Find the smallest molar proportion

Divide both by the smaller number

N: 2.175 / 2.175 = 1

O: 4.346875 / 2.175 = 1.999 = 2

5) Empirical formula: NO2

6) mass of the empirical formula

14.00 + 2 * 16.00 = 46.00 g

7) Find the number of moles of the gas using the equation pV = nRT

=> n = pV / RT = (775/760) atm * 0.389 l / (0.0821 atm*l /K*mol * 273.15K)

=> n = 0.01769 moles

8) Find molar mass

molar mass = mass in grams / number of moles = 1.63 g / 0.01769 mol = 92.14 g / mol

9) Find how many times the mass of the empirical formula is contained in the molar mass

92.14 / 46.00 = 2.00

10) Multiply the subscripts of the empirical formula by the number found in the previous step

=> N2O4

Answer: N2O4
3 0
3 years ago
Three blocks are shown here pls HELPPPP:
White raven [17]

Answer: I am confident the answer is B

Explanation:

forgive me if im wrong

5 0
3 years ago
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