Is heating sulfur and copper a physical or chemical change?

PLEASE HELP CHEMITRY!

Delicious77 [7]

Answer:

.

Explanation:

5 0

3 years ago

Which of the following solvent pairs could be used in a solvent pair recrystallization (in general, not for this specific reacti

lilavasa [31]

Answer:

(a) Ethyl acetate and hexane, and (c) methanol and methylene chloride.

Explanation:

re-crystallization is a technique used to purify solid compound. Ethyl acetate and hexane are good solvent pair for recrystallization because they are miscible with each other due to their good differences in polarity. ethyl acetate has polarity of 77 while hexane has 68.

water and diethyl ether are not good solvent pair for recrystallization because water and diethyl ether are immiscible. They have very far polarity values. water has 100 while diethyl ether has 35

3 0

3 years ago

A cart is rolling across the floor at a constant velocity of 2 m/s to the right. The cart is pushed again to the right, and it s

galben [10]

Answer: the answer is c.The unbalanced push causes the cart to speed up.

Explanation:

The application of an unbalanced force (the push) causes the cart to speed up. When the cart is in constant motion, the forces are balanced and there is no speeding up. Once an unbalanced force is added, the cart's speed changes.

6 0

4 years ago

Read 2 more answers

Draw the structure of 1,4-hexanediamine.

brilliants [131]

Answer:

1,4-hexanediamine contains two $-NH_{2}$ functional groups.

Explanation:

1,4-hexanediamine is an organic molecule which contains two $-NH_{2}$ functional groups at C-1 and C-4 position.

The longest carbon chain in 1,4-hexanediamine contains six carbon atoms.

Molecular formula of 1,4-hexanediamine is $C_{6}H_{16}N_{2}$ .

1,4-hexanediamine used as a bidentate ligand in organometallic chemistry.

The structure of 1,4-hexanediamine is shown below.

5 0

3 years ago

Calculate the number of O atoms in 0.364 g of CaSO4 · 2H2O

Nikolay [14]

Answer:

= 7.66 x 10²¹ oxygen atoms in 0.364 grams of CaSO₄·2H₂O

Explanation:

For problems like this posting, one needs an understanding of the following topics:

The definition of the mole

1 mole of substance = mass in grams of substance containing 1 Avogadro's Number ( = 6.023 x 10²³ ) of particles of the specified substance. This is generally one formula weight of the substance of interest. From this, the following equivalent relationships should be memorized:

1 mole = 1 formula weight = 1 mole weight (g)= 6.023 x 10²³ particles

Converting grams to moles:

Given grams => moles = grams/gram formula wt

Converting moles to grams:

Given moles => grams = moles x gram formula wt

_________________________________________________________

Calculate the number of O atoms in 0.364 g of CaSO₄ · 2H₂O.

Given mass CaSO₄ · 2H₂O = 0.364 grams

Formula Wt CaSO₄ · 2H₂O = 172 g/mole

moles CaSO₄ · 2H₂O = mass CaSO4 · 2H2O / formula Wt. CaSO₄ · 2H₂O

= 0.364 g CaSO₄·2H₂O / 172 g CaSO4·2H2O

= (0.364/172) mole CaSO₄·2H₂O

= 2.12 x 10⁻³ mole CaSO₄·2H₂O

∴ number of Oxy (O) atoms in 0.364 grams CaSO₄·2H₂O

= (2.12 x 10⁻³ mole CaSO₄ · 2H₂O)(6.023 x 10²³ molecules CaSO₄· 2H₂O/ mole)

= 1.276876 x 10²¹molecules CaSO₄· 2H₂O CaSO₄2H₂O

= 1.276876 x 10²¹ molecules CaSO₄· 2H₂O x 6 oxygen atoms / molecule

= 7.661256 x 10²¹ oxygen atoms in 0.364 grams of CaSO₄·2H₂O

= 7.66 x 10²¹ oxygen atoms in 0.364 grams of CaSO₄·2H₂O

8 0

3 years ago