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3 years ago

10

PLEASEEE HELP ME I AM REDOING MY CHEMISTRY UNIT TEST ON USATP (7TH GRADE) PLEASE HELP ME IF YOU KNOW ALL THE ANSWERS PLEASE LET

ME KNOW

2 answers:

Slav-nsk [51]3 years ago

6 0

Answer:

B) Copper

A) lonic bonds

B) Water

Ksju [112]3 years ago

3 0

Answer:

Dont cheat

Explanation:

Im in highschool and I fail for cheating now I cant go to college

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1. How is the modern periodic table organized?

Dimas [21]

1. How is the modern periodic table organized? Increasing atomic number

2. What information about an atom's properties can you read from the periodic table? Metal or not metal. Does it want to gain or lose electrons

3. How are the relationships of elements in a group different from the relationships of elements in a period? a group will have similar properties A period will have different properties

4. Would you expect Strontium (Sr) to be more like potassium (K) or bromine (Br)?

potassium

5. Barium (Ba) is in Group 2. Recall that atoms in Group 1 lose one electron to form ions with a 1+ charge. What type of ion does barium form? Ba+2

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3 years ago

One of relatively few reactions that takes place directly between two solids at room temperature is In this equation, the in Ba(

yuradex [85]

Answer:

3.14 grams of ammonium thiocyanate must be used to react completely with 6.5 g barium hydroxide octahydrate.

Explanation:

$Ba(OH)_2.8H_2O(s)+NH_4SCN(s)\rightarrow Ba(SCN)_2(s)+8H_2O(l)+NH_3(g)$

The balance chemical equation is :

$Ba(OH)_2.8H_2O(s)+2NH_4SCN(s)\rightarrow Ba(SCN)_2(s)+10H_2O(l)+2NH_3(g)$

Mass of barium hydroxide octahydrate = 6.5 g

Moles of barium hydroxide octahydrate = $\frac{6.5 g}{315 g/mol}=0.020635 mol$

According to reaction, 2 moles of ammonium thiocyanate reacts with1 mole of barium hydroxide octahydrate. The 0.020635 moles of barium hydroxide octahydrate will react with:

$\frac{2}{1}\times 0.020635 mol=0.04127 mol$

Mass of 0.04127 moles of ammonium thiocyanate;

$0.04127 mol\times 76 g/mol=3.136 g\approx 3.14 g$

3.14 grams of ammonium thiocyanate must be used to react completely with 6.5 g barium hydroxide octahydrate

3 0

4 years ago

I need help!! i need to make it like 3:2

anyanavicka [17]

Answer:

use visual studio code and put in this print{3:2}-1

Explanation:

4 0

3 years ago

Answer in detail?? What precautions would you take to protect yourself from an earthquake, when you are at home and when you are

Dmitry [639]

Answer:

If you're indoors, stay inside. If you're outside, stay outside. If you're indoors, stand against a wall near the center of the building, stand in a doorway, or crawl under heavy furniture (a desk or table). Stay away from windows and outside doors.

4 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