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3 years ago

Why are the alloys harder than pure iron

Chemistry

1 answer:

balu736 [363]3 years ago

6 0

Answer:

Explanation:

Alloys are harder and stronger because the different-sized atoms of the mixed metals make the atomic layers less regular, so they cannot slide as easily.

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What do these two changes have in common

neonofarm [45]

Both involve chemical bonds breaking

6 0

3 years ago

Read 2 more answers

A sample of Xe gas is observed to effuse through a pourous barrier in 4.83 minutes. Under the same conditions, the same number o

Solnce55 [7]

Answer:

28.93 g/mol

Explanation:

This is an extension of Graham's Law of Effusion where $\frac{R1}{R2} = \sqrt{\frac{M2}{M1} } = \frac{t2}{t1}$

We're only talking about molar mass and time (t) here so we'll just concentrate on $\sqrt{\frac{M2}{M1} } = \frac{t2}{t1}$ . Notice how the molar mass and time are on the same position, recall effusion is when gas escapes from a container through a small hole. The time it takes it to leave depends on the molar mass. If the gas is heavy, like Xe, it would take a longer time (4.83 minutes). If it was light it would leave in less time, that gives us somewhat an idea what our element could be, we know that it's atleast an element before Xenon.

Let's plug everything in and solve for M2. I chose M2 to be the unknown here because it's easier to have it basically as a whole number already.

$\sqrt{\frac{M2}{131} } = \frac{2.29}{4.83}$

The square root is easier to deal with if you take it out in the first step, so let's remove it by squaring each side by 2, the opposite of square root essentially.

$(\sqrt{\frac{M2}{131} } )^2= (\frac{2.29}{4.83})^2$

${\frac{M2}{131} } = (0.47)^2$

${\frac{M2}{131} } = 0.22$

M2= 0.22 x 131

M2= 28.93 g/mol

8 0

3 years ago

A kid on a playground swing makes 6 complete to-and-fro swings each 30 seconds.

Virty [35]

The frequency of swings is 12 ans the perios of swining is 3 min.

6 0

3 years ago

If i have 17 moles of gas at a temperature of 67c, and a volume of 88.89 liters what is the pressure of the gas

Shtirlitz [24]

Use the state equation for ideal gases: pV = nRT

Data:

V = 88.89 liter
n = 17 mol
T = 67 + 273.15 = 340.15 K

R = 0.0821 atm * liter / (K*mol)

=> p = nRT / V = 17 mol * 0.0821 (atm*liter / K*mol) * 340.15 K / 88.89 liter

p = 5.34 atm

Answer: p = 5.34 atm

4 0

3 years ago

The equation for the reaction between copper and nitric acid is vCu + wHNO3--->xCu(NO3)2 + yNO + zH2O Balance the equation an

lana [24]

Answer:

The coefficients of the balanced equation are:

v= 1
w= 4
x= 1
y= 2
z=2

Explanation:

The Law of Conservation of Matter, also called the Law of Conservation of Mass or the Lomonósov-Lavoisier Law, postulates that "mass is neither created nor destroyed, it is only transformed". This means that the reagents interact with each other and form new products with different physical and chemical properties than the reagents, but the amount of matter or mass before and after a transformation (chemical reaction) is always the same. In other words, then the mass before the chemical reaction is equal to the mass after the reaction.

Then, you must balance the following chemical equation:

v Cu + w HNO₃ → x Cu(NO₃)₂ + y NO + z H₂O

For that, you must first look at the subscripts next to each atom to find the number of atoms in the equation. If the same atom appears in more than one molecule, you must add its amounts

Left side: 1 copper, 1 hydrogen, 1 nitrogen and 3 oxygen.
Right side: 1 copper, 2 hydrogen, 3 nitrogen and 8 oxygen.

The coefficients located in front of each molecule indicate the amount of each molecule for the reaction. This coefficient can be modified to balance the equation, just as you should never alter the subscripts.

By multiplying the coefficient mentioned by the subscript, you get the amount of each element present in the reaction.

Generally, hydrogen and oxygen balance in the end. So you balance nitrogen first, because copper is already balanced (there is the same amount on both sides of the reaction). If w = 2, then:

Left side: 1 copper, 2 hydrogen, 2 nitrogen and 6 oxygen.
Right side: 1 copper, 2 hydrogen, 3 nitrogen and 8 oxygen.

But you see then that the oxygen is unbalanced and you have less quantity in the reagents. Then w must be greater. Being w = 4:

Left side: 1 copper, 4 hydrogen, 4 nitrogen and 10 oxygen.
Right side: 1 copper, 2 hydrogen, 3 nitrogen and 8 oxygen.

Going back to the idea of balancing nitrogen, being y = 2:

Left side: 1 copper, 4 hydrogen, 4 nitrogen and 10 oxygen.
Right side: 1 copper, 2 hydrogen, 4 nitrogen and 9 oxygen.

Balancing the hydrogen, being z = 2:

Left side: 1 copper, 4 hydrogen, 4 nitrogen and 10 oxygen.
Right side: 1 copper, 4 hydrogen, 4 nitrogen and 10 oxygen.

Since you have the same amount of each element on each side of the reaction, the reaction is balanced. Then, the balanced equation is:

Cu + 4 HNO₃ → Cu(NO₃)₂ + 2 NO + 2 H₂O

Finally:

v= 1
w= 4
x= 1
y= 2
z=2

6 0

3 years ago