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3 years ago

What is radioactivity.

1 answer:

5 0

Radioactivity another name for radioactive decay. Radioactivity refers to particles emitted from nuclei as a result of nuclear instability.

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Explain the “war of the currents” please help with at least 1 sentence

Alex777 [14]

Answer:

The war of the currents, sometimes called battle of the currents, was a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s.

Explanation:

3 0

3 years ago

2. Based on what you know about waves and light, do you think that light can be

ss7ja [257]

Answer:

Light as a wave: Light can be described (modeled) as an electromagnetic wave. In this model, a changing electric field creates a changing magnetic field. This changing magnetic field then creates a changing electric field and BOOM - you have light. ... So, Maxwell's equations do say that light is a wave.

Explanation:

Hope this helps

6 0

3 years ago

Read 2 more answers

A flask with a volume of 3.16 l contains 9.33 grams of an unknown gas at 32.0°c and 1.00 atm. What is the molar mass of the gas?

Inessa05 [86]

Answer:

73.88 g/mol

Explanation:

For this question we have to keep in mind that the unknown substance is a gas, therefore we can use the ideal gas law:

$PV=nRT$

In this case we will have:

P= 1 atm

V= 3.16 L

T = 32 ªC = 305.15 ºK

R= 0.082 $\frac{atm*L}{mol*K}$

n= ?

So, we can solve for "n" (moles):

$1~atm*3.16~L~=~n*0.082~\frac{atm*L}{mol*K}*305.15~K$

$n=\frac{1~atm*3.16~L~}{0.082~\frac{atm*L}{mol*K}*305.15~K}$

$n=0.126~mol$

Now, we have to remember that the molar mass value has "g/mol" units. We already have the grams (9.33 g), so we have to divide by the moles:

$molar~mass=\frac{9.33~grams}{0.126~mol}$

$molar~mass=73.88\frac{grams}{mol}$

7 0

3 years ago

Where the oxygen comes from the air (21% O2 and 79% N2). If oxygen is fed from air in excess of the stoichiometric amount requir

guajiro [1.7K]

Answer:

$y_{O2} =4.3$ %

Explanation:

The ethanol combustion reaction is:

$C_{2}H_{5} OH+3O_{2}$ → $2CO_{2}+3H_{2}O$

If we had the amount (x moles) of ethanol, we would calculate the oxygen moles required:

$x*1.10(excess)*\frac{3 O_{2}moles }{etOHmole}$

Dividing the previous equation by x:

$1.10(excess)*\frac{3 O_{2}moles}{etOHmole}=3.30\frac{O_{2}moles}{etOHmole}$

We would need 3.30 oxygen moles per ethanol mole.

Then we apply the composition relation between O2 and N2 in the feed air:

$3.30(O_{2} moles)*\frac{0.79(N_{2} moles)}{0.21(O_{2} moles)}=121.414 (N_{2} moles )$

Then calculate the oxygen moles number leaving the reactor, considering that 0.85 ethanol moles react and the stoichiometry of the reaction:

$3.30(O_{2} moles)-0.85(etOHmoles)*\frac{3(O_{2} moles)}{1(etOHmoles)} =0.75O_{2} moles$

Calculate the number of moles of CO2 and water considering the same:

$0.85(etOHmoles)*\frac{3(H_{2}Omoles)}{1(etOHmoles)}=2.55(H_{2}Omoles)$

$0.85(etOHmoles)*\frac{2(CO_{2}moles)}{1(etOHmoles)}=1.7(CO_{2}moles)$

The total number of moles at the reactor output would be:

$N=1.7(CO2)+12.414(N2)+2.55(H2O)+0.75(O2)\\ N=17.414(Dry-air-moles)$

So, the oxygen mole fraction would be:

$y_{O_{2}}=\frac{0.75}{17.414}=0.0430=4.3$ %

6 0

3 years ago

Can someone help.? thanks :)

laila [671]

Answer:

1. Equation: 2x + 3 = 9x - 11

2. Each row has 2 chairs

Explanation:

The variable x represents the number of chairs in each row.

1. She can form 2 rows of a given length with 3 chairs left over.

Thus, she has:

number of rows number of chairs in chairs number of chairs

each row left over she has

2 x 3 2x + 3

2. She can form 9 rows of the same length if she gets 11 more chairs.

That means that she is short in 11 chairs to have 9x chairs, or that she has 11 less chairs than 9x chairs. Then she has:

9x - 11

3. Equation:

Then, number of chairs she has is 2x + 3 and, also, 9x - 11, which allows to set the equation:

2x + 3 = 9x -11

4. Solve the equation:

9x - 2x = 3 + 11

7x = 14

x = 2

Therefore, each row has 2 chairs, and she has 2x + 3 = 4 + 3 = 7 chairs.

4 0

4 years ago