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3 years ago

What do SPF sunscreen and ozone in the earths atmosphere do

Chemistry

1 answer:

KiRa [710]3 years ago

8 0

Answer:

In much the same way that a cloud blocks the heat on a hot day, the ozone layer in the stratosphere blocks out the sun's deadly ultraviolet rays. It acts as our planet's natural sunblock.

Explanation:

PLZ MARK BRAINLIEST

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Chemical change example

lord [1]

Answer: burning paper

Explanation:

The paper burns in air to form smoke and ash. which makes it a chemical change.

3 0

3 years ago

The equilibrium constant Kp for the reaction I2(g) + Br2(g) ⇀↽ 2 IBr(g) + 11.7 kJ is 280 at 150◦C. Suppose that a quantity of IB

mixas84 [53]

Answer:

$\large \boxed{\text{0.0120 atm }}$

Explanation:

The balanced equation is

I₂(g) + Br₂(g) ⇌ 2IBr(g)

Data:

Kp = 280

p(IBr) = 0.200 atm

1. Set up an ICE table.

Let p = the initial pressure of IBr. Then

$\begin{array}{ccccccc}\rm \text{I}_{2}& + & \text{Br}_{2} & \, \rightleftharpoons \, & \text{2IBr} & & \\0 & & 0 & & p & & \\+x & & +x & & -2x & &\\x & & x} & & 280 & & \\\end{array}$

2. Calculate p(I₂)

$\begin{array}{rcl}K_{\text{p}}&=&\dfrac{p_{\text{IBr}}^{2}} {p_{\text{I}_2}^{2}}\\\\280&=&{\dfrac{0.200^{2}}{x^{2}}&&\\\\280x^{2} & = &0.0400\\x^{2} & = &\dfrac{0.0400}{280 }\\\\& = & 1.429 \times 10^{-4}\\x & = & \textbf{0.0120 atm}\\\end{array}\\\text{The partial pressure of iodine is $\large \boxed{\textbf{0.0120 atm }}$}$ }

Check:

$\begin{array}{rcl}{\dfrac{0.200^{2}}{0.0120^{2}}}&=&280\\\\280& =& 280\\\end{array}$

8 0

3 years ago

You react 2.43 grams of magnesium with oxygen from the air according to the following reaction. The final mass of the product, m

Leona [35]

Answer:

The mass of oxygen that reacted is approximately 1.6 grams of oxygen

Explanation:

The given information are;

The mass of magnesium in the reaction = 2.43 grams

The final mass of the magnesium oxide = 4.12 grams

The chemical equation for the reaction is given as follows;

2Mg + O₂ → 2MgO

From which we see that two moles of magnesium, Mg, reacts with one mole of oxygen gas molecule, O₂, to produce two moles of magnesium oxide, MgO

The number of moles of magnesium present, $n_{Mg}$ , is given as follows;

$n_{Mg} = \dfrac{Mass \ of \, magnesium}{Molar \ mass \ of \, magnesium} = \dfrac{2.43}{24.305} \approx 0.1 \ moles$

By the given chemical equation, 2 moles of magnesium reacts with one mole of O₂, therefore;

1 mole of magnesium will react with 1/2 moles of oxygen which is 0.5 moles of oxygen also;

0.1 mole of magnesium will react with 0.05 moles of oxygen

The mass of one mole of oxygen = The molar mass of oxygen = 32 g/mol

The mass of oxygen in the reaction = The number of moles of oxygen × The molar mass of oxygen

The mass of oxygen in the reaction = 0.05 × 32 = 1.6 grams

Also from the molar mass of MgO which is 40.3044 g/mol, we have;

The mass fraction of oxygen = 16/40.3044 = 0.39698 ≈ 0.4

The mass of oxygen = 0.39698 × 4.12 = 1.636 g

Therefore, the mass of oxygen in the reaction is approximately 1.6 grams.

8 0

3 years ago

I’m so lost please help

Vadim26 [7]

d= 8/10 so yah that was a guess

8 0

3 years ago

Na3po4 dissolves in water to produce an electrolytic solution. what is the osmolarity of a 2. 0 × 10-3 m na3po4 solution?

vichka [17]

When Na3po4 dissolves in water to produce an electrolytic solution. The osmolarity of a 2. 0 × 10-3 m Na3po4 solution is 0.008osmol/L.

Osmolarity is defined as the number of osmoles of solute particles per unit volume of the solution.

In other words osmolarity is the multiple if molarity

Osmolarity = i× molarity

Here i represents the van't Hoff factor,

$Na_{3}PO_{4}$ ⇒ $3Na^{+} + PO_{4} ^{-}$

3 Moles of $Na_{} ^{+}$ + 1 mole $PO_{4} ^{-}$ = 4

The number of moles of particles of solute produced in solution are actually called osmoles.

As a result, the van't Hoff factor will be equal to

i=4 Moles ions produced (osmoles) 1mole $Na_{3} PO_{4}$ .dissolved =4

Since we know that,

$Na_{3} PO_{4}$ = $2.0 * 10^{-3} M$

Osmolarity =

$4*2.0*10^{-3} M$ = $8.0 * 10^{-3} osmol L -10s$

Thus, the Osmolarity of given solution is 0.008 osmol/L.

learn more about Osmolarity:

brainly.com/question/13597129

#SPJ4

6 0

2 years ago