Helium and nickel are classified as _____, which are pure substances that make up all kinds of matter. Group of answer choices

Carbon and silicon are tetravalent but ge sn pb show di valency. Why

Anuta_ua [19.1K]

Answer:

Carbon and silicon both are tetravalent elements as compared to germanium, tin, and lead which are divalent.

That's because Ge, tin, and Pb show inert pair effect and has a greater nuclear effective charge on the 's' electrons due to poor shielding effect. .That's why these elements are not able to share their valence electrons while carbon and silicon does and show "catenation" which is the ability to form long chain molecules.

4 0

4 years ago

A mixture of methanol and methyl acetate contains 15.0 wt% methanol.

Usimov [2.4K]

The mixture flow rate in lbm/h = 117.65 lbm/h

<h3>Further explanation</h3>

Given

15.0 wt% methanol

The flow rate of the methyl acetate :100 lbm/h

Required

the mixture flow rate in lbm/h

Solution

mass of methanol(CH₃OH, Mw= 32 kg/kmol) in mixture :

$\tt 15\%\times 200~kg=30~kg\\\\mol=\dfrac{mass}{MW}=\dfrac{30~kg}{32~kg/kmol}=0.9375~kmol$

mass of the methyl acetate(C₃H₆O₂,MW=74 kg/kmol,85% wt) in 200 kg :

$\tt 85\%\times 200=170~kg\\\\mol=\dfrac{170}{74}=2.297~kmol$

Flow rate of the methyl acetate in the mixture is to be 100 lbm/h.

1 kg mixture = 0.85 .methyl acetate

So flow rate for mixture :

$\tt \dfrac{1~kg~mixture}{0.85~methyl~acetat}\times 100~lbm/h=117.65~lbm/h$

5 0

3 years ago

Can someone help me on some of these question please : )

frez [133]

X-Ray used to Take images of teeth and bones.
Ultraviolet night vision goggle

4 0

4 years ago

A burner on a stove produces?

loris [4]

Answer:

thermal energy

Explanation:

7 0

3 years ago

A sample of propane(c3h8)has 3.84x10^24 H atoms.

deff fn [24]

Answer:

A) 14. 25 × 10²³ Carbon atoms

B) 34.72 grams

Explanation:

1 molecule of Propane has 3 atoms of Carbon and 8 atoms of Hydrogen.

The sample has 3.84 × 10²⁴ H atoms.

If 8 atoms of Hydrogrn are present in 1 molecule of propane.

3.84 × 10²⁴ H atoms are present in

$\mathfrak{ \frac{3.8 }{8} \times 10 ^{24}}$

= 4.75 × 10²³ molecules of Propane.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

No. of Carbon atoms in 1 molecule of propane = 3

=> C atoms in 4.75× 10²³ molecules of Propane = 3 × 4.75 × 10²³

= 14.25 × 10²³ 

________________________________________

Gram Molecular Mass of Propane(C3H8)

= 3 × 12 + 8 × 1

= 36 + 8

= 44 g

1 mole of propane weighs 44g and has 6.02× 10²³ molecules of Propane.

=> 6.02 × 10²³ molecules of Propane weigh = 44 g

=> 4. 75 × 10²³ molecules of Propane weigh =

$\mathsf{ \frac{44 }{6.02 \times {10}^{23} } \times 4.75 \times {10}^{23} }$

$\mathsf{ = \frac{44 }{6.02 \times \cancel{{10}^{23} }} \times 4.75 \times \cancel{ {10}^{23}} }$

$\mathsf{ = \frac{44 }{6.02 } \times 4.75 }$

= 34.72 g

8 0

3 years ago