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Anna11 [10]
3 years ago
15

What is the percent by mass of oxygen in ca(oh)2? [formula mass = 74.1]

Chemistry
2 answers:
andre [41]3 years ago
8 0
16(2)/74.1=.431

.431x100= 43.1%
finlep [7]3 years ago
8 0

Answer:

43.18%

Explanation:

To calculate the percentage by mass of oxygen in the compound, multiply the atomic mass of oxygen by two. This is done because the compound contains two moles of oxygen.

16*2=32

32 divided by the formula mass as given in the question multiplied by 100 gives 43.18%

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I’ve been stuck on these 5 questions!? Can you guys help?!
Varvara68 [4.7K]

Answer:

1. 0.224 moles of oxygen

3. 143.36 L oxygen gas

5. 0.059 atm

10. 5.14 atm

11. 307 K

Explanation:

1. You have to use the ideal gas law: PV=nRT where P is pressure in atm, V is volume in liters, n is number of moles, R is the constant 0.08206 L atm mol^-1 K^-1, and T is the temperature in Kelvins where K=degrees celsius+273.15 . By rearranging the equation, you solve for n, which is n=(PV)/(RT)

P= 28.3 atm

V=0.193 L

R= 0.08206 L atm mol^-1 K^-1

T= 24.5+273.15= 297.65 K

Plugging the values in,

n=(28.3 atm x 0.193 L)/(0.08206 L atm mol^-1 K^-1 x 297.65 K)

n= 0.224 moles of oxygen

3. At STP, there are 22.4 L of gas for every mole of gas present. So 6.4 moles of oxygen would mean that there are:

6.4 mol x 22.4 L= 143.36 L oxygen gas

5. You have to use the ideal gas law: PV=nRT where P is pressure in atm, V is volume in liters, n is number of moles, R is the constant 0.08206 L atm mol^-1 K^-1, and T is the temperature in Kelvins where K=degrees celsius+273.15 . By rearranging the equation, you solve for P, which is       P=(nRT)/V

n= 0.72 g converting to moles, divide by molar mass of oxygen gas:        0.72 g/32g= 0.0225 moles

V=9.3 L

R= 0.08206 L atm mol^-1 K^-1

T= 23.0+273.15= 296.15 K

Plugging the values in,

P=(0.0225 moles x 0.08206 L atm mol^-1 K^-1 x 296.15 K)/ 9.3 L

P= 0.059 atm

10. Ideal gas law again using the same equation as 5 above: You have to use the ideal gas law: PV=nRT where P is pressure in atm, V is volume in liters, n is number of moles, R is the constant 0.08206 L atm mol^-1 K^-1, and T is the temperature in Kelvins where K=degrees celsius+273.15 . By rearranging the equation, you solve for P, which is P=(nRT)/V

n= 0.108 mol

R=0.08206 L atm mol^-1 K^-1

T=20.0+273.15= 293.15 K

V= 0.505 L

Plugging the values in,

P=(0.108 mol x 0.08206 L atm mol^-1 K^-1 x 293.15 K)/0.505 L

P= 5.14 atm

11. You have to use the ideal gas law: PV=nRT where P is pressure in atm, V is volume in liters, n is number of moles, R is the constant 0.08206 L atm mol^-1 K^-1, and T is the temperature in Kelvins where K=degrees celsius+273.15 . By rearranging the equation, you solve for Y, which is T=(PV)/(nR)

P= 0.988 atm

V= 1.20 L

n= 0.0470 mol

R=0.08206 L atm mol^-1 K^-1

Plugging the numbers in,

T=(0.988 atm x 1.20 L)/(0.0470 mol x 0.08206 L atm mol^-1 K^-1)

T= 307 K

4 0
3 years ago
In an endothermic reaction would energy be considered a reactant or a product?
timurjin [86]

Answer:

In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic reaction, the opposite is true. The products have less stored chemical energy than the reactants. The excess energy in the reactants is released to the surroundings

4 0
3 years ago
How much mercury and oxygen could be obtained from 21.7g of mercury (II) oxide
Musya8 [376]

20.06 g of Hg  and 1.6 g of O₂

<u>Explanation:</u>

To Find:

Number of Mercury and oxygen that can be obtained from 21.7 g of HgO

First we have to write the balanced equation for the decomposition reaction of Mercury(II) oxide as,

2 HgO (s) → 2Hg(l) + O₂ (g)

21.7 g of HgO  = \frac{21.7 g}{216.59  g / mol}  

                         = 0.1 mol of HgO.

As per the above equation, we can find the mole ratio between HgO and Hg is 1: 1 and that of HgO and oxygen is 2:1 .

So amount of Hg produced = 0.1 mol × 200.59 g / mol ( molar mass of Hg)

                                                 = 20.06 g of Hg

Amount of oxygen produced = 0.05  mol × 32 g/ mol = 1.6 g of O₂

Thus it is clear that 20.06 g of Hg  and 1.6 g of O₂  is obtained from 21.7 g of HgO

7 0
3 years ago
What so ammonia and bleach make
Law Incorporation [45]

Answer:

Mixing bleach and ammonia will create a toxic chloramine gas. Exposure to chloramine gas can cause irritation to your eyes, nose, throat, and lungs .

if you do accidentally mix bleach and ammonia, get out of the contaminated area and into fresh air immediately.

hope this help u ☆

8 0
3 years ago
WILL GIVE BRAINLIEST AND POINTS!!
Aleksandr [31]

Answer:

H2O= +2

CCl4 = +4

Na+= 0

CuCl2= -2

5 0
3 years ago
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