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3 years ago

DIRECTIONS: Use the Word Bank to answer the questions below. For questions 2 and 3 circle the correct choice.

Chemistry

1 answer:

Angelina_Jolie [31]3 years ago

8 0

Explanation:

1. Electrons surround the nucleus in defined regions called orbits.

2. The shells further away from the nucleus are larger and can hold more electrons.

3. The shells closer to the nucleus are smaller and can hold less electrons.

4. The closest shell (closest to the nucleus) can hold a maximum of two electrons.

5. Once the first shell is full, the second shell begins to fill. It can hold a maximum of eight electrons.

6. Once the second shell is full, the third shell begins to fill.

7. Once the third shell contains Eighteen electrons, the fourth shell begins to fill.

8. The arrangement of electrons in shells around the nucleus is referred to as an atom's electronic configuration.

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If an instrument has 10 ml td +/- 0.01 ml written on it, the user should ..... question 5 options: record 10 ml in the notebook

galina1969 [7]

Answer : The correct option is "record 10.00 ml in the notebook after using it."

Explanation :

If an instrument has "10 mL TD" written on it, that means the instrument is meant To Deliver (TD) 10 mL of volume.

Therefore the option that has 5.00 mL is not correct.

"+/- 0.01 mL" indicates the precision of the instrument. We know that no measurement is 100% accurate and there is always some uncertainty associated with any measurement.

Here, 0.01 indicates the uncertainty in the measurement.

When we have 0.01 mL , that means the instrument can record precisely to the hundredths place.

The more the significant figures, the greater is the accuracy of the measurement.

Therefore when we use an instrument that has "+/- 0.01 mL" written on it, we should record the reading as 10.00 mL

6 0

3 years ago

5. Select the answer for both questions

salantis [7]

Answer:

engey

Explanation:

7 0

2 years ago

A 3.140 molal solution of NaCl is prepared. How many grams of NaCl are present in a sample containing 2.692 kg of water

S_A_V [24]

Answer:

494.49 g of NaCl.

Explanation:

Data obtained from the question include the following:

Molality of NaCl = 3.140 m

Mass of water = 2.692 kg

Mass of NaCl =.?

Next, we shall determine the number of mole of NaCl in the solution.

Molality is simply defined as the mole of solute per unit kilogram of solvent. Mathematically, it is expressed as

Molality = mole of solute /Kg of solvent

With the above formula, we can obtain the number of mole NaCl in the solution as follow:

Molality of NaCl = 3.140 m

Mass of water = 2.692 kg

Mole of NaCl =..?

Molality = mole of solute /Kg of solvent

3.140 = mole of NaCl /2.692

Cross multiply

Mole of NaCl = 3.140 x 2.692

Mole of NaCl = 8.45288 moles

Finally, we shall covert 8.45288 moles of NaCl to grams. This can be obtained as follow:

Mole of NaCl = 8.45288 moles

Molar mass of NaCl = 23 + 35.5 = 58.5 g/mol

Mass of NaCl =.?

Mole = mass /Molar mass

8.45288 = mass of NaCl /58.5

Cross multiply

Mass of NaCl = 8.45288 × 58.5

Mass of NaCl = 494.49 g.

Therefore, 494.49 g of NaCl are present in the solution.

8 0

3 years ago

Stells [14]

Answer:

40%

Explanation:

Calculate the percent of the mass that is carbon:

$\% mass = \frac{80}{200} \times 100 = 40\%$

7 0

3 years ago

1.8 mol HCl and 3.3 mol NaOH react accord- ing to the equation HCl + NaOH −→ NaCl + H2O . Calculate the amount in moles of NaCl

ollegr [7]

Answer:

1.8 moles of NaCl must be produced.

Explanation:

Based on the reaction:

HCl + NaOH → NaCl + H2O

1 mol of HCl reacts with 1 mol of NaOH to produce 1mol of NaCl

To solve this question we must find, as first, the limiting reactant:

1.8 moles of HCl will need 1.8 moles of NaOH for a complete reaction (Ratio of reaction 1:1). As there are 3.3 moles of NaOH,

HCl is limiting reactant

When the 1.8 moles of HCl react completely,

1.8 moles of NaCl must be produced because 1 mole of HCl produce 1 mole of NaCl

5 0

3 years ago