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3 years ago

Which of the following best describes a physical change?*

Chemistry

2 answers:

Dennis_Churaev [7]3 years ago

5 0

Answer:

Explanation:

i had this question and i got it right

KATRIN_1 [288]3 years ago

4 0

Answer:

Explanation:

I took this test way back

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A reaction was suppose to produce 20 L of gas. Only 12 litters of gas were produced in the lab. What is the percent yield for th

pogonyaev

Answer:

$\boxed {\boxed {\sf 60 \%}}$

Explanation:

Percent yield is a ratio of the actual yield to the theoretical yield. It is found using this formula:

$\% \ yield= \frac {actual \ yield}{theoretical \ yield} *100$

The actual yield is 12 liters, because that was actually produced in the lab.

The theoretical yield is 20 liters, because that was the expected yield.

$\% \ yield= \frac {12 \ L}{20\ L} *100$

$\% \ yield= 0.6*100$

$\% \ yield= 60$

For this reaction, the percent yield is 60%.

5 0

3 years ago

A solution contains 0.115 mol h2o and an unknown number of moles of nacl. the vapor pressure of the solution at 30°c is 25.7 tor

Valentin [98]

According to Raoult's low:
We will use this formula: Vp(Solution) = mole fraction of solvent * Vp(solvent)
∴ mole fraction of solvent = Vp(Solu) / Vp (Solv)
when we have Vp(solu) = 25.7 torr & Vp(solv) = 31.8 torr
So by substitution:
∴ mole fraction of solvent = 25.7 / 31.8 =0.808
when we assume the moles of solute NaCl = X
and according to the mole fraction of solvent formula:
mole fraction of solvent = moles of solvent / (moles of solvent + moles of solute)
by substitute:
∴ 0.808 = 0.115 / (0.115 + X)
So X (the no.of moles of NaCl) = 0.027 m

8 0

3 years ago

2. What do acidic solutions have high concentrations of?

Xelga [282]

Hydrogen ions
mark me brainlist

7 0

3 years ago

Read 2 more answers

Given bh3, o3, co2, and nh3, which of these compound is an exception to the octet rules?.

Ghella [55]

Answer:

a. BH₃

Explanation:

According to the octet rules, atoms reach stability when are surrounded by eight electrons in their valence shell when they combine to form a chemical compound.

From the options, the only compound in which the central atom does not meet the octet rules is BH₃. The central atom is boron (B), which has 3 electrons in its valence shell. When B is combined with hydrogen (H), 3 electrons from the 3 atoms of H are added. The total amount of electrons is 6, fewer than 8 electrons needed to meet the rule.

hope this helps

5 0

2 years ago

1. Complete the following

Marat540 [252]

Answer:

$\large \boxed{\text{0.603 mol}}$

Explanation:

We must do the conversions

mass of C₆H₁₂O₆ ⟶ moles of C₆H₁₂O₆ ⟶ moles of O₂

We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.

Mᵣ: 180.16

C₆H₁₂O₆ + 6O₂ ⟶ 6CO₂ + 6H₂O

m/g: 18.1

(a) Moles of C₆H₁₂O₆

$\text{Moles of C$_{6}$H$_{12}$O}_{6} = \text{18.1 g C$_{6}$H$_{12}$O}_{6}\times \dfrac{\text{1 mol C$_{6}$H$_{12}$O}_{6}}{\text{180.16 g C$_{6}$H$_{12}$O}_{6}}\\\\= \text{0.1005 mol C$_{6}$H$_{12}$O}_{6}$

b) Moles of O₂

$\text{Moles of O}_{2} =\text{0.1005 mol C$_{6}$H$_{12}$O}_{6} \times \dfrac{\text{6 mol O}_{2}}{\text{1 mol C$_{6}$H$_{12}$O}_{6}} = \text{0.603 mol O}_{2}\\\\\text{The reaction requires $\large \boxed{\textbf{0.603 mol}}$ of oxygen}$

3 0

3 years ago