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2 years ago

And this one too please

Chemistry

1 answer:

weqwewe [10]2 years ago

3 0

Answer: Groups 15 and 16.

Explanation:

All other answer choices include metals, which form ionic bonds.

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An element crystallizes in a face-centered cubic lattice. If the length of an edge of the unit cell is 0.408 nm, and the density

V125BC [204]

Answer:

Explanation:

For the density of a face-centered cubic:

$Density = \dfrac{4 \times M_w}{N_A \times a^3}$

where

$M_w$ = molar mass of the compound

$N_A=$ avogadro's constant

$a^3 =$ the volume of a unit cell

Given that:

Density $(\rho)$ = 19.30 g/cm³

a = 0.408 nm

a = $0.408 \times 10^{-9} \times 10^{2} \ cm$

a = $4.08 \times 10^ {-8} \ cm$

∴

$19.3 = \dfrac{4 \times M_w}{(6.023 \tmes 10^{23})\times (4.08 \times 10^{-8})^3}$

$M_w= \dfrac{19.3\times (6.023 \times 10^{23})\times (4.08 \times 10^{-8})^3}{4}$

$M_w=197.37 \ g/mol$

Thus, the molar mass of 197.37 g/mol element is Gold (Au).

4 0

3 years ago

People who work with radioactive materials often wear a _________ to reveal how much radiation they have been exposed to. A. fil

nekit [7.7K]

People who work with radioactive materials often wear a film badge to reveal how much radiation they have been exposed to. The film badge dosimeter or the film badge is a dosimeter worn by these people working with materials that are radioactive for the purpose of monitoring cumulative radiation dose due to ionizing radiation. The badge has two parts; the photographic film, and a holder.

3 0

3 years ago

Read 2 more answers

A 33.0 mL sample of 1.15 M KBr and a 59.0 mL sample of 0.660 M KBr are mixed. The solution is then heated to evaporate water unt

Oksi-84 [34.3K]

Answer:

We need 13.06 grams of silver nitrate to precipitate out silver bromide in the final solution

Explanation:

Step 1: Data given

Sample 1: The 1.15 M sample has a volume of 33.O mL

Sample 2: The 0.660 M sample has a volume of 59.0 mL

Molar mass of KBr = 119 g/mol

Molar mass of AgNO3 = 169.87 g/mol

Step 2: Calculate number of moles for both samples

Number of moles = Molarity * Volume

Sample 1: 1.15 M * 33 *10^-3 L = 0.03795 moles

Sample 2: 0.660 M *59*10^-3 L = 0.03894 moles

Total mol KBr = 0.03795 + 0.03894 = 0.07689 moles

Step 3: Calculate total mass

mass = Number of moles * Molar mass

mass = 0.07689 moles * 119 g/moles = 9.15 grams ( in 55mL)

Step 4: Calculate moles of AgBr

AgNO3 reacts with KBr

KBr(aq) + AgNO3(aq) → AgBr(s) + KNO3(aq)

1 mole of KBr consumed, needs 1 mole of AgNO3 to produce 1 mole of AgBr and 1 mole of KNO3

So 0.07689 moles of KBr wll need 0.07689 moles of AgNO3

Step 5: Calculate mass of silver nitrate

mass of AgNO3 = Moles of AgNO3 * Molar mass of AgNO3

mass of AgNO3 = 0.07689 moles * 169.87 g/mol = 13.06 grams

We need 13.06 grams of silver nitrate to precipitate out silver bromide in the final solution

8 0

3 years ago

BRAINLIESTTT ASAP!!!! PLEASE HELP ME :)

Elan Coil [88]

Answer:

1s² 2s²2p³

Explanation:

If the atom has seven electrons, it is Element 7 (nitrogen).

In the Periodic Table, you count the electrons in all the subshells up to

No. 7.

In the first Period, you have filled the 1s level (2 electrons).

In the second Period, you have filled the 2s subshell (2 electrons) and put three electrons in the 2p subshell.

Thus, the electron configuration is

1s² 2s²2p³

Note how the superscripts tell you the number of electrons in each subshell: 2 + 2 + 3 = 7.

6 0

2 years ago

At exactly 2:00 PM, speedy the hermit crab crawl onto a meter stick starting at the 10 cm mark. If he reaches the 60 cm mark at

kvv77 [185]

Answer:

speed=5cm/minute

Explanation:

Given at 2:00PM the hermit is at 10cm mark

Also given that the hermit reaches 60cm mark at 2:10PM

Therefore the time elapsed is 10 minutes = $10\times 60=600 seconds$

the distance travelled by the hermit is 60-10=50cm=0.5m

We know that

$speed=\frac{distane}{time}$

$speed=\frac{0.5}{600}$

speed = $8.3\times 10^{-4}$ m/sec=5cm/minute

3 0

3 years ago