Last one i think.......

What is the charge of the ions formed by Na and by Cl?

Alexxandr [17]

Answer:

Na+ is positively charged as it loses an electron

Cl- is negatively charged as it gains an electron

3 0

3 years ago

Po−218 is an alpha emitter with a half-life of 3.0 minutes. if a sample contains 59 mg of po−218, how many alpha emissions would

Naddik [55]

<span>1.4x10^20 alpha emissions. First, determine how many atoms of Po-218 you have. Do this by dividing the mass by 218 to get the number of moles, then multiply by Avogadro's number: 0.059 g / 218 g/mol * 6.0221409x10^23 atoms/mol = 1.63x10^20 atoms. Now we need to figure out how many half lives we're going to be observing the polonium. So take the time that we'll be observing and divide by the half life. So 9.0 / 3.0 = 3.0 So we're going to be spending 3 half lives. That means that only 2^-3, or 0.125 = 12.5 percent of the original polonium will be left. Which means that 100% - 12.5% = 87.5% of the atoms will have decayed. So let's figure that out. 0.875 * 1.63x10^20 = 1.43x10^20 Rounding to 2 significant figures gives 1.4x10^20 alpha emissions.</span>

5 0

3 years ago

PLEASE HELP WILL MARK AS BRAINLEST

zlopas [31]

Answer:

The deer population will grow

This is because the Moutain Lions were eating the deer and now nothing is eating them.

8 0

3 years ago

How many moles of chlorine are used up in a reaction that produces 0.35kg of BCl3

maw [93]

4.48 mol Cl2. A reaction that produces 0.35 kg of BCl3 will use 4.48 mol of Cl2.

(a) The <em>balanced chemical equation </em>is

2B + 3Cl2 → 2BCl3

(b) Convert kilograms of BCl3 to moles of BCl3

MM: B = 10.81; Cl = 35.45; BCl3 = 117.16

Moles of BCl3 = 350 g BCl3 x (1 mol BCl3/117.16 g BCl3) = 2.987 mol BCl3

(c) Use the <em>molar ratio</em> of Cl2:BCl3 to calculate the moles of Cl2.

Moles of Cl2 = 2.987 mol BCl3 x (3 mol Cl2/2 mol BCl3) = 4.48 mol Cl2

4 0

3 years ago

The pressure of a gas sample was measured to be 654 mmhg. What is the pressure in kpa? (1 atm = 1. 01325 × 10 5 pa)

Stels [109]

Taking into account the change of units, the pressure of the gas sample is 87.19 kPa.

<h3>What is rule of three</h3>

In first place, the rule of three is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them.

That is, what is intended with it is to find the fourth term of a proportion knowing the other three.

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied.

To solve a direct rule of three, the following formula must be followed, being a, b and c known data and x the variable to be calculated:

a ⇒ b

c ⇒ x

So: $c=\frac{cxb}{a}$

<h3>Pressure</h3>

The direct rule of three is the rule applied in this case where there is a change of units.

To perform in this case the conversion of units, you must first know that:

1 atm= 760 mmHg
1 atm = 1. 01325×10⁵ Pa= 101325 Pa
1 kPa= 1000 Pa

So, if 1 atm is 760 mmHg, how many atm equals 654 mmHg?

760 mmHg ⇒ 1 atm

654 mmHg ⇒ x

So: $x=\frac{654 mmHgx1 atm}{760 mmHg}$

Solving:

Now, if 101325 Pa are 1 atm, how many Pa equals 0.86 atm?

1 atm ⇒ 101325 Pa

0.86 atm ⇒ x

So: $x=\frac{0.86 atmx101325 Pa}{1 atm}$

Solving:

Finally, if 1 kPa is 1000 Pa, how many kPa equals 87,192.83 Pa?

1000 Pa ⇒ 1 kPa

87,192.83 Pa ⇒ x

So: $x=\frac{87,192.83 Pax1 kPa}{1000 Pa}$

Solving:

In summary, the pressure of the gas sample is 87.19 kPa.

Learn more with this example:

brainly.com/question/12482948

#SPJ12

5 0

2 years ago