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3 years ago

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7.7. A painter leans his back against a painted wall while looking into a 1m long mirror at the opposite end of a rectangular ro

om as shown in the given figure. How much of the painted wall can he see through the given mirror?
a. 1m
b. 2m
c. 12m
d. 6m

1 answer:

Karolina [17]3 years ago

8 0

Answer:

Correct answer is b) 2m

Explanation:

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An unknown substance is obtained by police. The forensics laboratory has

timurjin [86]

Answer:

70.0 %

Explanation:

Step 1: Given data

Mass of nitrogen (mN): 74.66 g

Mass of the compound (mNxOy): 250 g

Step 2: Calculate the mass of oxygen (mO) in the compound

The mass of the compound is equal to the sum of the masses of the elements that form it.

mNxOy = mN + mO

mO = mNxOy - mN

mO = 250 g - 74.66 g = 175 g

Step 3: Determine the percent composition of oxygen in the sample

We will use the following expression.

%O = mO / mNxOy × 100%

%O = 175 g / 250 g × 100% = 70.0 %

5 0

3 years ago

CAN SOMEONE HELP ME PLZ AND THANKS WILL MARK U AS BRAINLIEST

jekas [21]

Explanation:

2. $2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O$

First, we need to find the number of moles of $CO_2$ at 300K and 1.5 atm using the ideal gas law:

$n= \dfrac{PV}{RT}= \dfrac{(1.5\:\text {atm})(33\:L)}{(0.082\:\text{L-atm/mol-K})(300K)}$

$=2.0\:\text{mol}\:CO_2$

Now use the molar ratios to find the number of moles of ethane to produce this much $CO_2$ .

$2.0\:\text{mol}\:CO_2 \times \left(\dfrac{2\:\text{mol}\:C_2H_6}{4\:\text{mol}\:CO_2}\right)$

$=1.0\:\text{mol}\:C_2H_6$

Finally, convert this amount to grams using its molar mass:

$1.0\:\text {mol}\:C_2H_6 \times \left(\dfrac{30.07\:\text g\:C_2H_6}{1\:\text{mol}\:C_2H_6} \right)$

$=30.1\:g\:C_2H_6$

3. $3Zn + 2H_3PO_4 \rightarrow 3H_2 + Zn_3(PO_4)_2$

Convert 75 g Zn into moles:

$75\:\text g\:Zn \times \left(\dfrac{65.38\:\text g\:Zn}{1\:\text{mol}\:Zn}\right)=1.1\:\text{mol}\:Zn$

Then use the molar ratios to find the amount of H2 produced.

$1.1\:\text{mol}\:Zn \times \left(\dfrac{3\:\text{mol}\:H_2}{3\:\text{mol}\:Zn}\right)=1.1\:\text{mol}\:H_2$

Now use the ideal gas law $PV=nRT$ to find the volume of H2 produced at 23°C and 4 atm:

$V= \dfrac{nRT}{P}= \dfrac{(1.1\:\text{mol}\:H_2)(0.082\:\text{L-atm/mol-K})(296K)}{4\:\text{atm}}$

$=8.9\:\text L\:H_2$

8 0

3 years ago

The pressure in an automobile tire filled with air is 245.0 kPa. If Po2 = 51.3 kPa, Pco2 = 0.10 kPa, and P-others = 2.3 kPa, wha

Kay [80]

Answer:

PN₂ = 191.3 Kpa

Explanation:

Given data:

Total pressure of tire = 245.0 Kpa

Partial pressure of PO₂ = 51.3 Kpa

Partial pressure of PCO₂ = 0.10 Kpa

Partial pressure of others = 2.3 Kpa

Partial pressure of PN₂ = ?

Solution:

According to Dalton law of partial pressure,

The total pressure inside container is equal to the sum of partial pressures of individual gases present in container.

Mathematical expression:

P(total) = P₁ + P₂ + P₃+ ............+Pₙ

Now we will solve this problem by using this law.

P(total) = PO₂ + PCO₂ + P(others)+ PN₂

245 Kpa = 51.3 Kpa + 0.10 Kpa + 2.3 Kpa + PN₂

245 Kpa = 53.7 Kpa+ PN₂

PN₂ = 245 Kpa - 53.7 Kpa

PN₂ = 191.3 Kpa

6 0

3 years ago

Which solution contains the biggest amount of chloride ions?

Katen [24]

Answer:

the quantity of solution to moles for d is significantly lower.

Explanation:

the larger the amount of liquid, the less amount of ions to dissociate hence having a lesser amount of chloride ions.

compared to b which is less liquid and a higher concentration

4 0

3 years ago

Which describes 5 molecules of water?<br> 1. 2 H2O<br> 2. H2O3<br> 3. 5 H2O

Phantasy [73]

Answer:

Water is a chemical compound and polar molecule, which is liquid at standard temperature and pressure. It has the chemical formula H2O, meaning that one molecule of water is composed of two hydrogen atoms and one oxygen atom.

Explanation:

5 0

3 years ago