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2 years ago

Which statement describes the difference between metallic bonds and Van der Waals forces? O

Chemistry

2 answers:

prohojiy [21]2 years ago

8 0

Answer: C

Explanation: Just took the test on a.p.e.x.

viktelen [127]2 years ago

4 0

Answer:

O C. Metallic bonds hold metal atoms and freely moving valence electrons together, while Van der Waals forces hold nonpolar molecules together.

Explanation:

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Slicing an average loaf of bread gives 13 medium thickness slices. Each slice of bread is to be coated with 0.0500 oz of mayonna

AlexFokin [52]

Answer:

36 loaves of bread and 18.48 ounces of mayonnaise are needed to make all of the sandwiches.

Explanation:

Number of slices of ham = 231

Given that each sandwich has 1 slice of ham.

Then 231 slices of ham will be in :

$1\times 231 =231 sandwiches$

A single sandwich is made up of 2 bread slices , Then bread slices in 231 sandwiches will be :

$231\times 2=462$

Each bread slice is applied with 0.0500 ounce of mayonnaise.

Then 462 bread slices will have :

$462\times 0.0500 ounces=18.48 Oz$

1 bread loaf = 13 bread slices

Then breads loves in 462 bread slices :

$\frac{462}{13}=35.54\approx 36$

36 loaves of bread and 18.48 ounces of mayonnaise are needed to make all of the sandwiches.

8 0

3 years ago

A heterogeneous mixture is a :

4vir4ik [10]

The correct answer is letter C. mixture in which its components retain their identity. A heterogeneous mixture is a mixtures in which the component of the mixed are not uniform. You can see that there are localized regions that have different properties. The components have the capacity to retain their identity.

8 0

2 years ago

Read 2 more answers

A chemistry student needs to standardize a fresh solution of sodium hydroxide. He carefully weighs out 28.mg of oxalic acid H2C2

Nezavi [6.7K]

Answer:

The molarity of the student's sodium hydroxide solution is 0.0219 M

Explanation:

1) Chemical reaction.

a) Kind of reaction: neutralization

b) General form: acid + base → salt + water

c) Word equation:

sodium hydroxide + oxalic acid → sodium oxalate + water

d) Chemical equation:

NaOH + H₂C₂O₄ → Na₂C₂O₄ + H₂O

b) Balanced chemical equation:

2NaOH + H₂C₂O₄ → Na₂C₂O₄ + 2H₂O

2) Mole ratio

2mol Na OH : 1 mol H₂C₂O₄ :1 mol Na₂C₂O₄ : 2 mol H₂O

3) Starting amount of oxalic acid

mass = 28 mg = 0.028 g
molar mass = 90.03 g/mol
Convert mass in grams to number of moles, n:

n = mass in grams / molar mass = 0.028 g / 90.03 g/mol = 0.000311 mol

4) Titration

Volume of base: 28.4 mL = 0.0248 liter
Concentration of base: x (unknwon)

Number of moles of acid: 2.52 mol (calculated above)

Proportion using the theoretical mole ratio (2mol Na OH : 1 mol H₂C₂O₄)

$\frac{2}{1} =\frac{x}{2.52}\\ \\ \\x=0.000311(2)=0.000622$

That means that there are 0.000622 moles of NaOH (solute)

5) Molarity of NaOH solution

M = n / V (liter) = 0.000622 mol / 0.0284 liter = 0.0219 M

That is the correct number using three signficant figures, such as the starting data are reported.

5 0

2 years ago

Read 2 more answers

Unit conversions.(a) Convert 10,000 dynes to units of lbm ∙ ft/s^2 and lbf(b) Convert 0.2 atm to units of Kpa and lbf/in^2(c) Co

Maru [420]

Answer:

(a) 0.72 lbm· ft/s²

(b) 20.3 kPa, 2.94 lbf / in²

(d) 1.5 x 10⁻² J, 6.1 x 10⁻² cal

Explanation:

Our strategy here will be to find the conversion factors for the quantities we are asked in each part, and perform the calculations.

(a) 10,000 dynes to lbm ·ft/s²

here we are asked to convert the force of 10,000 dynes to lbm ·ft/s². Recall that F= ma ( m= mass, a = acceleration), thus

10,000 dynes = 10 g cm/s²

converting the force

10,000 g cm/s² x (1 lbm/454 g) x (1 ft / 30.48 cm ) /s² = 0.72 lbm· ft/s²

(b)

1 atm = 101.33 pa

0.2 atm x ( 101.33 kPa ) = 20.3 kPa

1 atm = 14.7 lbf / in²

0.2 atm x ( 14.7 lbf / in² /atm ) = 2.94 lbf / in²

ºF = 9/5 ºC +32

ºF = 9/5 ( 37ºC) + 32 = 98.6 ºF

K = ºC + 273

K = (37 + 273) K = 310 K

(d) 50 in²·lbm/s² to joules and calories

Since the unit in² ·lbm/s² is not that common, lets convert it using their definition.

These are energy units, and we know the energy is the force times distance. In turn force is mass times acceleration so that the units of energy are mass time distance per time squared.

Joules is the unit of energy in the metric system.

50 in² lbm/s² = 50 in²x ( 2.54 cm/in x 1m /100cm)² x (1lbm x 0.454 Kg/lbm)/s²

= 1.5 x 10⁻² Kg m²/² = 1.5 x 10⁻² J

To convert to cal it wilñl be easier to use the value in joules just calculated:

1.5 x 10⁻² J x (4.184 cal/J) = 6.1 x 10⁻² cal

4 0

3 years ago

Explain how you can use boyle's law to determine the new volume of gas when its pressure is increased from 270 kPa to 540 kPa? T

LUCKY_DIMON [66]

There are several information's already given in the question. Based on the information's the answer can be easily deduced.

We know the formula

P1*V1/T1 = P2*V2/T2

As the temperature is constant, so T1 and T2 can be negated. The formula changes to
P1*V1 = P2*V2
70 * 1 = 540 * V2
270/540 = V2
V2 = 0.5

From the above deduction, we can conclude that the new volume is 0.5 liters. I hope that the procedure is clear enough for you to understand.

7 0

3 years ago