Can someone please answer questions 32 and 33?

Which of the following laboratory procedures best illustrates the law of conservation of mass?

11111nata11111 [884]

it would be heating of 32g of s and 56g of Fe to produce 88g of FeS and unused reactants

5 0

3 years ago

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One type of sunburn occurs when skin is exposed

julia-pushkina [17]

Answer:

E = 6.27 × 10⁻²³ Joules

Explanation:

E = h (Plancks constant) × f (frequency)

(Plancks constant = 6.63 × 10⁻³⁴ J×s)

f = λ × c (used to find frequency so you can satisfy energy equation)

*Have to find wavelength in meters to multiply by speed of light*

1. f = (3.15 × 10⁻⁷ m) × (3 × 10⁸ m/s)

2. f = 9.45 × 10¹⁰ s

3. E = (6.63 × 10⁻³⁴ J×s [Plancks constant]) × (9.45 × 10¹⁰ s)

E = 6.27 × 10⁻²³ Joules

8 0

3 years ago

Considering that the mantle is 44.8% oxygen and 21.5% silicon by mass, calculate the mole ratio of oxygen atoms to silicon atoms

horrorfan [7]

The mantle has a mass of around $4.278 X 10 ^2^4 kg$ that is around 68.4% of earth's mass.

So to calculate moles we need to first find out the mass of oxygen and silicon present in mantle. It is given that oxygen is 44.8% by mass in mantle and 21.5% by mass in mantle, therefore to calculate its mass, we need to use $\text{mass percentage }=\frac{\text{mole of solute}}{\text{mass of solution}}\times100$

Now, to calculate mass percentage of oxygen

$44.8 =\frac{x}{4.278X10^2^4kg}\times100$

$x= 191.65\times10^2^2kg$

Similarly the mass of silicon can be calculated

$21.5 =\frac{x}{4.278X10^2^4kg}\times100$

$x=91.977\times10^2^2kg$

Now, the moles of any substance is calculated by

$\text{moles}= \frac{\text{given mass}}{\text{molar mass}}$

$\text{moles of oxygen}= \frac{191.65\times10^2^2kg}{2.6566962\times10^-^2^6kg}$

where, mass of oxygen in kilograms is $2.6566962\times10^-^2^6kg$

So, $\text{moles of oxygen}=72.1384\times10^4^8\text{moles of O}$

Similarly $\text{moles of silicon}= \frac{91.977\times10^2^2kg}{4.663\times10^-^2^6kg}$

$\text{moles of silicon}=19.724\times10^4^8\text{moles of Si}$

Now, to calculate mole ratio we need to divide every moles to the lowest calculated mole that is the moles of Si and round it off to the nearest whole number.

$\text{mole ratio of oxygen}= \frac{72.138\times10^4^8kg}{19.724\times10^4^8kg}$

$=3.65\approx 4$

$\text{mole ratio of Silicon}=\frac{19.724\times10^4^8}{19.724\times10^4^8}$

$=1$

$\text{Mole ratio of Oxygen : Mole ratio of Silicon} = 4:1$

6 0

4 years ago

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HCL is pure covalent compound but soluble in solvent water why

Marina CMI [18]

Answer:

HCl is a polar covalent compound, because of electronegativity difference between Cl(3.5) and hydrogen (2). Hence in this way, the bond between HCl breaks and they formed ions in the polar solvent like water .

6 0

3 years ago

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A compound has the name iodine pentafluoride. What kind of bond is present between the atoms? A. O Metallic B Covalent C. Hydrog

8090 [49]

Answer:

IF(subscript 5)

Explanation:

covalent.

3 0

3 years ago