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tatyana61 [14]
3 years ago
10

4=2 (r – 8)please help​

Chemistry
2 answers:
Triss [41]3 years ago
4 0

Answer:

r = 10

Explanation:

4 = 2 ( r - 8 )

4 = 2r - 16

20 = 2r

10 = r

trasher [3.6K]3 years ago
3 0

4=2(r-8)\implies2=r-8\implies r=10.

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What is the volume of 3.5 moles of oxygen gas (O2) at standard temperature and pressure (STP)?
baherus [9]
1 mole ----------- 22.4 L ( at STP )
3.5 mols --------- ?

V  = 3.5 x 22.4 / 1

V = 78.4 L

hope this helps!


4 0
3 years ago
Question Megan made a model of the respiratory system using a water bottle and balloons. When she pulled down on the balloon str
ruslelena [56]

Answer:

The lung

Explanation:

The model of the respiratory system made by Megan consists of two balloons. The first balloon stretched across the bottom of the bottle represents the diaphragm which contracts and relaxes to allow air in and out of the lungs. The balloon inside the bottle represents one lung.

Breathing in causes the balloon inside the bottle to be filled with air. This is preceded by the expansion of the diaphragm which makes the lungs to be filled with air. Breathing out causes a contraction of the diaphragm thus making the lungs to let out air.

4 0
3 years ago
Read 2 more answers
10.
Andru [333]

Answer: 1.8 moles Fe and 2.7 moles CO_2 are produced.

Explanation:

The balanced chemical reaction is:

Fe_2O_3+3CO\rightarrow 2Fe+3CO_2  

According to stoichiometry :

3 moles of CO require 1 mole of Fe_2O_3

Thus 2.7 moles of CO will require=\frac{1}{3}\times 2.7=0.9moles  of Fe_2O_3

Thus CO is the limiting reagent as it limits the formation of product and Fe_2O_3 is the excess reagent.

As 3 moles of CO give = 2 moles of Fe  and 3 moles of CO_2

Thus 2.7 moles of CO will give =\frac{2}{3}\times 2.7=1.8moles  of Fe  and \frac{3}{3}\times 2.7=2.7moles  of CO_2

Thus 1.8 moles Fe and 2.7 moles CO_2 are produced.

7 0
3 years ago
We make a basic solution by mixing 50. mL of 0.10 M NaOH and 50. mL of 0.10 M Ca(OH)2. It requires 250 mL of an HCl solution to
andreyandreev [35.5K]

<u>Answer:</u> The correct answer is Option 5.

<u>Explanation:</u>

  • To calculate the molarity of the solution after mixing 2 solutions, we use the equation:

M=\frac{n_1M_1V_1+n_2M_2V_2}{V_1+V_2}

where,

n_1,M_1\text{ and }V_1 are the n-factor, molarity and volume of the NaOH.

n_2,M_2\text{ and }V_2 are the n-factor, molarity and volume of the Ca(OH)_2

We are given:

n_1=1\\M_1=0.10M\\V_1=50mL\\n_2=2\\M_2=0.1\\V_2=50mL  

Putting all the values in above equation, we get:

M=\frac{(1\times 0.1\times 50)+(2\times 0.1\times 50)}{50+50}\\\\M=0.15M

  • To calculate the molarity of acid, we use the equation given by neutralization reaction:

n_1M_1V_1=n_2M_2V_2

where,

n_1,M_1\text{ and }V_1 are the n-factor, molarity and volume of acid which is HCl

n_2,M_2\text{ and }V_2 are the n-factor, molarity and volume of base.

We are given:

n_1=1\\M_1=?M\\V_1=250mL\\n_2=1\\M_2=0.15M\\V_2=100mL

Putting values in above equation, we get:

1\times M_1\times 250=1\times 0.15\times 100\\\\M_1=0.06M

Hence, the correct answer is Option 5.

7 0
3 years ago
How is the number of moles of an element determined from a known mass?
goblinko [34]

the mass of 1 mole of the element is used as a conversion factor to convert grams to moles

4 0
4 years ago
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