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3 years ago

Which process is a chemical change

2 answers:

5 0

The process of a chemical change is when it occur when a substance called chemical synthesis or alternatively chemical decomposition into two or more different substances

Airida [17]3 years ago

5 0

Answer:

Loss of atmospheric ozone

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a chemist uses hot hydrogen gas to convert chromium (iii) oxide to pure chromium. how many grams of hydrogen are needed to produ

MA_775_DIABLO [31]

Answer:

Explanation:

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6 0

3 years ago

Suppose you want to create a 6 ng/μL solution in a 25 mL volumetric flask. However, this concentration cannot really be accurate

Over [174]

Answer:

Mass of chemical = 1.5 mg

Explanation:

Step 1: First calculate the concentration of the stock solution required to make the final solution.

Using C1V1 = C2V2

C1 = concentration of the stock solution; V1 = volume of stock solution; C2 = concentration of final solution; V2 = volume of final solution

C1 = C2V2/V1

C1 = (6 * 25)/ 0.1

C1 = 1500 ng/μL = 1.5 μg/μL

Step 2: Mass of chemical added:

Mass of sample = concentration * volume

Concentration of stock = 1.5 μg/μL; volume of stock = 10 mL = 10^6 μL

Mass of stock = 1.5 μg/μL * 10^6 μL = 1.5 * 10^6 μg = 1.5 mg

Therefore, mass of sample = 1.5 mg

4 0

3 years ago

Determine the empirical formula of the compound formed when 1.2g of magnesium reacts with 3.55g of chlorine.Take the molar mass

masha68 [24]

Explanation:

For Mg, (1.2 g Mg/24 g Mg) = 0.05 mol Mg.

For Cl, (3.55 g Cl/35.5 g Cl) = 0.1 mol Cl

So the ratio now is

Mg:Cl = 0.05 : 0.1 = 1:2

I got the 1:2 ratio by dividing both by the smallest number, which is 0.05 mol. Therefore, the empirical for formula of the substance is $MgCl_2$

5 0

3 years ago

The average atomic weight of copper, which has two naturally occurring isotopes, is 63.5. One of the isotopes has an atomic weig

Darya [45]

<u>Answer:</u> The atomic weight of the second isotope is 64.81 amu.

<u>Explanation:</u>

Average atomic mass of an element is defined as the sum of atomic masses of each isotope each multiplied by their natural fractional abundance

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$ .....(1)

We are given:

Let the mass of isotope 2 be 'x'

Mass of isotope 1 = 62.9 amu

Percentage abundance of isotope 1 = 69.1 %

Fractional abundance of isotope 1 = 0.691

Mass of isotope 2 = 'x'

Percentage abundance of isotope 2 = 30.9%

Fractional abundance of isotope 2 = 0.309

Average atomic mass of copper = 63.5 amu

Putting values in equation 1, we get:

$\text{Average atomic mass of copper}=[(62.9\times 0.691)+(x\times 0.309)]$

$x=64.81amu$

Hence, the atomic weight of second isotope will be 64.81 amu.

4 0

3 years ago

50 POINTS!!!! PLEASE HELP I AM BEGGING!!!!!!

polet [3.4K]

3CH4 refers to three molecules of a
compound and C3H12 refers to only one
molecule of a compound.
3CH4 and C3H12 are actually different
molecules though they contain the same
number and types of atoms. Recall that both
of them are hydrocarbons hence they
contain only hydrogen and carbon.
3CH4 refers to three molecules of methane
while C3H12 refers to one molecule of
diphenyl methane. Hence 3CH4 refers to
three molecules of a compound and C3H12
refers to only one molecule of a compound.

7 0

3 years ago