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4 years ago

PLEASE HELP ASAP

1 answer:

5 0

I believe its true , because when two elements form different compounds a given mass of one element will combine with the other , during any chemical change atoms arent created or destroyed they are jus rearranged

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What is the most likely electronegativity value for a metallic element? (1) 1.3 (2) 2.7 (3) 3.4 (4) 4.0

morpeh [17]

The answer is 1. This is because electronegativity increases up a group and across a period. So metals are going to be the least electronegative. 4.0 is the most electronegative element on Paulina's Scale!

4 0

3 years ago

Read 2 more answers

What are the rows of the periodic table called?

Sergio039 [100]

Answer:

"The elements are arranged in seven horizontal rows,called periods or series,and 18 vertical columns,called Groups."

Explanation:

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4 0

3 years ago

What are the mole fraction and the mass percent of a solution made by dissolving 0.21 g KBr in 0.355 L water? (d = 1.00 g/mL.) m

IRISSAK [1]

Answer:

Mol fraction H2O = 0.99991

Mol fraction KBr = 0.00009

mass % KBr = 0.059 %

mass % H2O = 99.941 %

Explanation:

Step 1: Data given

Mass of KBr = 0.21 grams

Molar mass KBr = 119 g/mol

Volume of water = 355 mL

Density of water = 1.00 g/mL

Molar mass water = 18.02 g/mol

Step 2: Calculate mass water

Mass water = 355 mL * 1g /mL

Mass water = 355 grams

Step 3: Calculate moles water

Moles water = mass water / molar mass water

Moles water = 355 grams / 18.02 g/mol

Moles water = 19.7 moles

Step 4: Calculate moles KBr

Moles KBr = 0.21 grams / 119 g/mol

Moles KBr = 0.00176 moles

Step 5: Calculate total moles

Total moles = 19.7 moles + 0.00176 moles

Total moles = 19.70176 moles

Step 6: Calculate mol fraction

Mol fraction H2O = 19.7 moles / 19.70176 moles

Mol fraction H2O = 0.99991

Step 7: Calculate mol fraction KBr

Mol fraction KBr = 0.00176 / 19.70176

Mol fraction KBr = 0.00009

Step 6: Calculate mass %

mass % KBR = (0.21 grams / (0.21 + 355) grams) *100%

mass % KBr = 0.059 %

mass % H2O = (355 grams / 355.21 grams) *100%

mass % H2O = 99.941 %

8 0

3 years ago

An analysis of a sugar compound is found to contain 132 grams of carbon (C), 22 grams of hydrogen (H), and 176 grams of oxygen (

ddd [48]

132 g of C , 22 g of H , 176 g of O

132 + 22 + 176 => 330 g of the substance

Now convert the masses in moles :

C = 12.0 u H = 1.0 u O = 16.0 u

C = 132 / 12.0 => 11 moles

H = 22 / 1.0 => 22 moles

O = 176 / 16.0 => 11 moles

Using the values obtained the lowest proportion in mols of elements present, simply divide the values found for the least of them:

C = 11 / 11 => 1

H = 22 / 11 => 2

O = 11 / 11 => 1

formula empirically is : CH₂O

hope this helps!

8 0

4 years ago

How are the codes (chemical formulas) for elements different from those for compounds?

DanielleElmas [232]

a) Two or more atoms held together with bonds make up a molecule. b) Pure substances are made of only one type of atom. c) At least two types of atoms are required to make a compound. d) Mixtures can be made of two elements, two compounds, or an element & a compound.

3 0

3 years ago

*PLEASE HELP ASAP*

PLEASE HELP ASAP