Bob rides his horse 52 km in 3 hours 15 minutes. What is his average speed in kilometers per hour?

There are two common isotopes of the element lithium. The first isotope has 3 protons and 3 neutrons. The second isotope has 3 p

lions [1.4K]

Hey there!

In hyphenated notation, we have the name of the element, a hyphen, then a number that is the sum of protons and neutrons.

The first isotope has 3 protons and 3 neutrons, so the sum is 6. Its name is lithium-6.

The second isotope has 3 protons and 4 neutrons, so the sum is 7. Its name is lithium-7.

Hope this helps!

4 0

4 years ago

In the chrysanthemums how are Elisa and the chrysanthemus si

Korolek [52]

The same or what I don't understand?

8 0

3 years ago

Choose the aqueous solution below with the highest freezing point. These are all solutions of nonvolatile solutes and you should

Inessa [10]

Answer: c. 0.200 m HOCH2CH2OH

Explanation:

The collective properties of solvents expressed that the freezing point of water is lowered when solute particles are dissolved in it.

When more particles are dissolved, the more the freezing point is deepened and lowered.

Here, all the molarities are equal, the deciding factor in measuring the lowering will be which substance produces the fewest particles in solution; then we relate it to lowering of the freezing point.

Ba(NO3)2 ---> Ba2+ + 2NO3(1-)

1 mol releases 3 mol of ions.

Mg(ClO4)2 ---> Mg2+ + 2ClO4(1-)

1 mol releases 3 mol of ions.

HOCH2CH2OH is covalent and doesn't ionize.

1 mol in water is just 1 mol of molecules.

Na3PO3 ---> 3Na+ + PO3(1-)

1 mol releases 4 mol ions.

The substance that produces the fewest particles in solution is the 0.200 m HOCH2CH2OH

3 0

3 years ago

a compound contains 69.94 percent iron and 30.06 percent oxygen. what is its molecular formula if the molar mass of the compound

anyanavicka [17]

The percentages are given in weight. You need to transform them into moles.

Take a basis of 100 grams of compound. Then there are 69.94 grams of iron and 30.06 grams of oxygen.

Use the atomic masses of iron and oxygen to obtain each number of moles.

Molar mass of iron: 55.85 g/mol
# moles of iron = 69.94 g / 55.85 g/mol = 1.252

Molar mass of oxygen: 16 g/mol
# moles of oxygen = 30.06 g / 16 g/mol =1.87875

Proportions

1.87875 moles of Oxigen/ 1.252moles of iron = 1.50 /1

3moles of Oxygen: 1 mol of Iron

Empirical formula: FeO3

Molar mass of the empirical formula: 55.85 g/mol + 3(16g/mol) = 103.85 g/mol

Molar mass of the compound / molar mass of the empirical formula = 199.55 g/mol / 103.85 g/mol = 1.92

Round to 2.

Then the molecular formula is the empirical formula times 2.

Fe2O6

6 0

3 years ago

When heating a substance, a phase change will start to occur when the kinetic energy of the particles is ___________________ the

Nezavi [6.7K]

Great enough overcome

7 0

4 years ago

Bob rides his horse 52 km in 3 hours 15 minutes. What is his average speed in kilometers per hour?​

Bob rides his horse 52 km in 3 hours 15 minutes. What is his average speed in kilometers per hour?