Please help me asap!

Lynna [10]

Answer:

$\boxed {\boxed {\sf D. 0.440 \ mol \ NaOH}}$

Explanation:

To convert from moles to grams, the molar mass is used (mass of 1 mole). The values are the same as the atomic masses on the Periodic Table, but the units are grams per mole (g/mol) instead of atomic mass units.

<h3>1. Molar Mass</h3>

We are given the compound sodium hydroxide (NaOH) and we need to look up the molar masses of the individual elements.

Na: 22.9897693 g/mol
O: 15.999 g/mol
H: 1.008 g/mol

The formula for the compound has no subscripts, so there is 1 mole of each element in 1 mole of the substance. We can simply add the molar masses.

NaOH: 22.9897693 + 15.999 + 1.008 = 39.9967693 g/mol

This means there are 39.9967693 grams of sodium hydroxide in 1 mole.

<h3>2. Convert Grams to Moles </h3>

Use the molar mass we found as a ratio.

$\frac {39.9967693 \ g \ NaOH}{ 1 \ mol \ NaOH}$

Since we are converting 17.6 grams of NaOH to moles, we multiply by this value.

$17.6 \ g\ NaOH *\frac {39.9967693 \ g \ NaOH}{ 1 \ mol \ NaOH}$

Flip the ratio so the units of grams of NaOH cancel.

$17.6 \ g\ NaOH *\frac {1 \ mol \ NaOH}{ 39.9967693 \ g \ NaOH}$

$17.6 *\frac {1 \ mol \ NaOH}{ 39.9967693}$

$\frac{17.6 }{ 39.9967693} \ mol \ NaOH$

$0.4400355406 \ mol \ NaOH$

<h3>3. Round </h3>

The original measurement of grams has 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place.

0.4400355406

The 0 in the ten thousandths place (in bold above) tells us to leave the 0 in the thousandth place.

$0.440 \ mol \ NaOH$

17.6 grams of sodium hydroxide are equal to <u>0.440 moles of sodium hydroxide.</u>

3 0

2 years ago

Hydrogen is unique among the elements because __________. 1. It has only one valence electron. 2. It is the only element that ca

Talja [164]

Answer:

3,4

Explanation:

Hydrogen has no other electron hence there is no screening of the valence electron by inner electrons. It is the lightest known element with a relative molecular mass of 2. Screening effect refers to the fact that inner or core electrons prevent the outermost electron from feeling the attractive force of the nucleus.

6 0

3 years ago

The nonvolatile, nonelectrolyte testosterone, C19H28O2 (288.40 g/mol), is soluble in benzene C6H6. Calculate the osmotic pressur

dolphi86 [110]

Answer:

3.824 atm

Explanation:

From the ideal gas equation

P = mRT/MW × V

m is mass of testosterone = 12.9 g

R is gas constant = 82.057 cm^3.atm/mol.K

T is temperature of benzene solution = 298 K

MW is molecular weight of testosterone = 288.40 g/mol

V is volume of benzene solution = 286 ml = 286 cm^3

P = 12.9×82.057×298/288.4×286 = 3.824 atm

6 0

2 years ago

What happened to the celery if you put in food color water

mixer [17]

Answer:

the celery would change colour!

Explanation:

8 0

3 years ago

What is the total number of moles represented by 20 grams of CACO3

Nutka1998 [239]

Answer:

B. 0.2.

Explanation:

We can use the relation:

<em>n = mass/molar mass</em>

mass of CaCO₃ = 20 g, molar mass of CaCO₃ = 100.0869 g/mol.

<em>∴ n = mass/molar mass = </em>(20 g)/(100.0869 g/mol) <em>= 0.1998 ≅ 0.2 mol.</em>

<em>So, the right choice is: B. 0.2.</em>

8 0

3 years ago