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pickupchik [31]
3 years ago
11

When 1.375 g of copper (II) oxide is reduced on heating in a current of hydrogen, the weight of copper remaining after the react

ion is complete is 1.098 g. What is the percent composition of oxygen?
Chemistry
1 answer:
nasty-shy [4]3 years ago
7 0

Answer:

20.11% of oxygen

Explanation:

The reaction is:

2CuO ⇒ 2Cu + O2

If you have an initial amoung of a sample, thi may be have impurities, so you have to start from products to know what you had at the begining.

to make a relation between reagents and products you need to change the mass to mol, then you can relate them with the molar ratio.

1,098gCu x \frac{1mol Cu}{63.546g Cu} x \frac{2mol CuO}{2molCu} x \frac{1mol O}{1molCuO} x \frac{16gO}{1molO} = 0,276gO

Now you have the initial amount of oxygen, to convert to percent you must divide the mass of oxygen between the mass of the sample and multiply by 100

percent composition of O = \frac{0.276gO}{1.375g sample} *100 = 20.11

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staci is attending a music festival. the ticket to the festival costs $87.96, Staci pleans to purchase $30.00 t-shirts from the
ziro4ka [17]

The total amount that Staci had in hand is $200.00.

The ticket at that time costs $87.96.

One Tshirt costs, $30.00.

Now that she has paid ticket, she will deduct the ticket from the cash she has in hand, so as to know the amount she is remaining with.

Tha is, $200-$87.96 = $112.04.

∴ In hand Staci has $112.04 extra cash whereby she can purchase more t shirts.

To get the number of tshirt she can buy, she will divide the amount she has in hand by the amount per piece of t shirt.

For example, $112.04 / $30 = $3.73.

∴ Staci can only purchase threet shirts only at a total cost of $90 for all the t shirts which is $30 × 3 = $90.

Staci has excess of 22.04 after deducting ticket and the other amount she has used to purchase the extra t shirts.

That is, $112.04 - $90 = $22.04.

3 0
3 years ago
Read 2 more answers
Why is it important to living things that water is bonded by h bond and not by covalent or ionic one
nexus9112 [7]
Because im pretty sure the molecules would just fall apart like salt which is ionic
8 0
3 years ago
Object A at 40ºC and object B at 80ºC are placed in contact with each other. Which statement describes the heat flow between the
Arada [10]
By the second law of thermodynamics:
Heat can not spontaneously flow from cold regions to hot regions without external work being performed on a system.
Heat transfer is the passage of thermal energy from a hot ( t B = 80° C ) to a colder body ( t A = 40° C ). 
Answer:  B ) Heat flows from object B to object A.
6 0
3 years ago
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How many molecules are contained in 125 grams of water, H20?
sergejj [24]
Answer:

18,01528

Explanation:
8 0
2 years ago
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A 44.0 g sample of an unknown metal at 99.0 oC was placed in a constant-pressure calorimeter of negligible heat capacity contain
tatiyna

Answer:

C_m=0.474\frac{J}{g\°C}

Explanation:

Hello.

In this case, since this is a system in which the water is heated up and the metal is cooled down in a calorimeter which is not affected by the heat lose-gain process, we can infer that the heat lost by the metal is gained be water, it means that we can write:

Q_m=-Q_w

Thus, in terms of masses, specific heats and temperatures we can write:

m_mC_m(T_{eq}-T_m)=-m_wC_w(T_{eq}-T_w)

Whereas the equilibrium temperature is the given final temperature of 28.4 °C and we can compute the specific heat of the metal as shown below:

C_m=\frac{-m_wC_w(T_{eq}-T_w)}{m_m(T_{eq}-T_m)}

Plugging the values in and since the density of water is 1.00 g/mL so the mass is 80.0g, we obtain:

C_m=\frac{-80.0g*4.184\frac{J}{g\°C} (28.4\°C-24.0\°C)}{44.0g(28.4\°C-99.0\°C)}\\\\C_m=0.474\frac{J}{g\°C}

Best regards!

6 0
3 years ago
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