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3 years ago

Mass and energy are conserved:

1 answer:

4 0

I believe B) in both chemical changes and physical changes since in chemical changes, nothing is created or destroyed. In physical changes same thing but with matter.

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What is the oxidation number of iron in FeO?

kiruha [24]

Answer:

Explanation:

3 0

3 years ago

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A piece of metal ore has a density of 1.72 g/mL. When a student places it into a graduated cylinder containing water, the liquid

Hunter-Best [27]

Answer:

Explanation:

Since..., Density = mass/volume

;Firstly calculate the volume change of the water when the metal is placed in,

;Volume = 26.47 - 21.25

;Volume = 5.22 mL

Hence the mass of the ore;

; Making mass the subject of formula in the above equation,

Mass = Density × Volume

; Mass = 1.72 × 5.22

; Hence the mass = 8.9784

= 9g

5 0

3 years ago

A sample of nitrogen gas has a volume of 478 cm3 and a pressure of 104.1 kPa. What volume would the gas occupy at 88.2 kPa if th

nadezda [96]

1. To solve this we assume that the gas is an ideal gas. Then, we can use the ideal gas equation which is expressed as PV = nRT. At a constant temperature and number of moles of the gas the product of PV is equal to some constant. At another set of condition of temperature, the constant is still the same. Calculations are as follows:

P1V1 =P2V2

V2 = P1 x V1 / P2

V2 = 104.1 x 478 / 88.2

V2 =564.17 cm^3

6 0

3 years ago

Read 2 more answers

All of the following are equal to Avogadro's number EXCEPT ____. a. the number of atoms of bromine in 1 mol Br2 b. the number of

Colt1911 [192]

All the following are equal to Avogadro's number EXCEPT a. the number of atoms of bromine in 1 mol Br₂.

1 mol Br₂ contains Avogadro’s number of molecules of Br₂.

However, each molecule contains two atoms of Br, so there are

2 × Avogadro’s number of Br atoms in 1 mol Br₂.

8 0

3 years ago

Ethane, C2H6, burns in oxygen. First write a balanced equation for this combustion reaction. What mass of oxygen, in grams, is r

iren [92.7K]

Answer:

We need 50.6 grams of oxygen

Explanation:

Step 1: Data given

Mass of ethane = 13.6 grams

Molar mass of ethane = 30.07 g/mol

Step 2: The balanced equation

2C2H6 + 7O2 → 4CO2 + 6H2O

Step 3: Calculate moles ethane

Moles ethane = mass ethane / molar mass ethane

Moles ethane = 13.6 grams / 30.07 g/mol

Moles ethane = 0.452 moles

Step 4: Calculate moles oxygen

For 2 moles ethane we need 7 moles O2 to produce 4 moles CO2 and 6 moles H2O

For 0.452 moles ethane we need 3.5*0.452 = 1.582 moles O2

Step 5: Calculate mass O2

Mass O2 = moles O2 * molar mass O2

Mass O2 = 1.582 moles * 32.0 g/mol

Mass O2 = 50.6 grams

We need 50.6 grams of oxygen

7 0

3 years ago