Given the standard enthalpies of formation for the following substances, determine

Consider the following isotopic symbol: 137Ba2+

aliya0001 [1]

Answer:

a) 56 protons

b) 54 electrons

c) 81 neutrons

d) The sum of protons and neutrons is shown. The number of protons is always the same. So we can calculate the number of neutrons ( and also the isotopes)

e)137Ba (with 56 protons and 81 neutrons)

f) atomic mass is 136.9 u ; the mass number is the sum of protons and neutrons and is 137

Explanation:

Step 1: Data given

137 Ba2+ is an isotope of barium. The atomic number of barium( and its isotopes) is 56. This shows the number of protons.

For a neutral atom, the number of protons is equal to the number of electrons.

The different isotopes of an element have the same number of protons but a different number of neutrons.

137Ba2+ has 56 protons (this is the same as the atomic number)

137Ba2+ has 54 electrons ( since it's Ba2+, this means it has 2 electrons less than protons, that's why it's charged +2)

137Ba2+ has 81 neutrons ( 137 - 56 = 81)

In the symbol, the atomic number is not shown. The sum of the protons and neutrons is shown. (Since the number of protons is the same for every isotope, we can calculate the number of neutrons that way. By knowing the neutrons, we also know the isotope.

This isotope is 137Ba

Atomic mass is also known as atomic weight. The atomic mass is the weighted average mass of an atom of an element based on the relative natural abundance of that element's isotopes.

The atomic mass of 137Ba2+ is 136.9 u

The mass number is a count of the total number of protons and neutrons in an atom's nucleus.

The mass number of 137Ba2+ is 137

3 0

3 years ago

9. Which of the following is true?

wlad13 [49]

The answer should be C

6 0

3 years ago

Sodium metal reacts with chlorine gas to produce sodium chloride. What mass (grams) of sodium metal would be needed to fully rea

gulaghasi [49]

Answer:

105.8 g of Na would be required

Explanation:

Let's think the reaction:

2Na(s) + Cl₂(g) → 2NaCl (s)

1 mol of chlorine reacts with 2 moles of sodium

Then, 2.3 moles of Cl₂ would react with (2.3 .2) / 1 = 4.6 moles

Let's determine the mass of them.

4.6 mol . 23 g/mol = 105.8 g

3 0

3 years ago

Which factor most influenced the economic

Vikki [24]

It was by far "warm and wet growing seasons" that was the most important factor in terms of the South's economic development. Cotton and tobacco were the biggest exports.

Explanation:

These crops created tons of cash, had massive markets round the world, however required a stable and enormous hands to grow and harvest them.The yank South is understood for its long, hot summers, and wealthy soils in stream valleys creating it a perfect location for growing cotton. the various southern seaports and riverside docks allowed shipping cotton to remote destinations. By 1860, Southern plantations equipped seventy fifth of the world's cotton, with shipments from Houston, city, Charleston, Mobile, Savannah, and some different ports. The unquenchable European demand for cotton was a results of the commercial Revolution that created the machinery and factories to method raw cotton into vesture that was higher and cheaper than hand-made product.

6 0

4 years ago

Read 2 more answers

Provide an example of a Food Chain.

VikaD [51]

Answer: Diamond is the name ^-^

A food chain only follows just one path as animals find food. eg: A hawk eats a snake, which has eaten a frog, which has eaten a grasshopper, which has eaten grass. A food web shows the many different paths plants and animals are connected. eg: A hawk might also eat a mouse, a squirrel, a frog or some other animal.

Hope this helps ^_^

5 0

3 years ago