I bake some flour until it turns into leavened bread. Is this a physical or chemical change? Why do you think this?

Two isotopes of hypothetical element X exist with abundances of 30.00% 100X and 70.00% 101X. What is the approximate atomic mass

Rasek [7]

Answer:

C. 100.7 amu

Explanation:

Isotopes of an element are atoms of an element with the same atomic number but different atomic masses. Each atomic mass of an isotope is known as an isotopic mass. An element that exhibits isotope, that is, that have two or more isotopes has a relative atomic mass that is not a whole number.

Relative atomic mass of X is the sum of the products of the relative abundances of each isotope and its isotopic mass.

For Isotope ¹⁰⁰X: 30% × 100 = 30 amu

For Isotope ¹⁰¹X: 70% × 101 = 70.7 amu

Relative atomic mass of X = (30 + 70.7) amu = 100.7 amu

Therefore, the approximate atomic mass of X is 100.7 amu

4 0

2 years ago

If you start with 89.3 g no(g) and 28.6 g h2(g), find the theoretical yield of ammonia.

Tatiana [17]

Balanced equation:
2 NO + 5 H2 ------> 2 NH3 + 2 H2O

2 moles NO react with 5 moles H2 to produce 2 moles NH3

Molar mass of NO = 30.00 g/mol 
86.3g NO = 86.3/30.00 = 2.877 moles of NO 

This will require: 2.877*5 / 2 = 7.192 moles of H2 

Molar mass of H2 = 2 g/mol 
25.6g H2 = 25.6/2 = 12.7 mol H2. 
You have excess H2 means the NO is limiting 

From the balanced equation: 
2 moles of NO will produce 2 moles of NH3 
2.877 moles of NO will produce 2.877 moles of NH3 

Molar mass NH3 = 17g/mol 
Mass NH3 produced = 2.877 * 17 = 48.91g

Hence the yield is = 48.91 g ~ 49 g

3 0

3 years ago

Read 2 more answers

What does kinetic molecular theory mean

oee [108]

Answer: gas particles that are in constant motion and exhibit perfectly elastic collisions

Explanation:

8 0

2 years ago

Read 2 more answers

What is the primary source of energy in most living communities?

klasskru [66]

Answer:

The sun

Explanation:

The sun is the primary source of energy in most living communities. The producers or the green plants that prepare their own food by the use of sunlight and other natural resources. Carbon dioxide, water, and other minerals are used by the plants to make their food in the presence of chlorophyll. Plants are then consumed by the consumers. This chain helps in forming the food chain and the food web.

4 0

3 years ago

The bond length in the HBr molecule is 1.41 Å. Calculate the dipole moments, in debyes, if the charges on the H and Br atoms wer

AfilCa [17]

Answer:

The Dipole moment is 6.77 Debyes.

Explanation:

Given bond length of HBr molecule = 1.41 A°,

We also know charges on H and Br(+1 and -1 respectively)

Charge on H = (+1) $\times$ (absolute charge of electron);