Ask question

Ask question

All categories

3 years ago

15

In science class, Jake mixed water with differing amounts of an unknown liquid. After mixing the liquids, he heated 20 millilite

rs (ml) of each mixture and observed how quickly it boiled. The table shows his results.

1 answer:

Snowcat [4.5K]3 years ago

7 0

Answer:

decrease i had the same question in 8th grade u must be in ninth

Explanation:

ohh im not sure but i think its A

You might be interested in

SOMEONE PLS HELP ME ITS URGENT

Simora [160]

If copper is heated with iron oxide there is no obvious reaction because

copper is less reactive than iron.

On a reactivity chart, copper is far below iron. This makes it impossible for a replacement reaction to occur, so the equation doesn't change.

I hope I helped!

5 0

3 years ago

Read 2 more answers

A student heats a sample of Copper (II) sulfate in a crucible and records the data shown in the table. What is the complete form

liberstina [14]

Explanation:

Copper (II) sulfate is usually present as a hydrous state, which is of the form CuSO4 * nH2O, where n is a whole number.

Mass of sample (CuSO4 * nH2O)

= 152.00g - 128.10g = 23.90g.

Mass of water loss during heating

= 152.00g - 147.60g = 4.40g.

Molar mass of H2O = 18g/mol

Moles of H2O in sample

= 4.40g / (18g/mol) = 0.244mol.

Mass of anhydrous sample (CuSO4)

= 23.90g - 4.40g = 19.50g

Molar mass of CuSO4 = 159.61g/mol

Moles of CuSO4 in sample

= 19.50g / (159.61g/mol) = 0.122mol.

Since mole ratio of CuSO4 to H2O

= 0.122mol : 0.244mol = 1:2, n = 2.

Hence we have CuSO4 * 2H2O.

6 0

3 years ago

Read 2 more answers

HOW FAST CAN YOU ANSWER

Alex777 [14]

Answer:

option "B" is correct (substance 2)

5 0

3 years ago

Which statements describing chemical and nuclear reactions are true?

alexdok [17]

Answer is: 2. Chemical reactions involve the rearrangement of electrons and 5. Isotopes of the same element behave differently in a nuclear reaction.

1) The electrons of an atom participates in a chemical reaction.

2) Chemical reactions involve the rearrangement of electrons, because there is transfer, loss, gain and sharing of electrons in chemical reactions.

3) Nuclear reactions can produce new elements, because number of protons and neutrons is changed.

4) Chemical reactions require heat or an input of energy to occur, this is activation energy.

5) Isotopes of the same element behave differently in a nuclear reaction, because isotopes have different number of neutrons, so products of a nuclear reaction is different.

8 0

3 years ago

What is the mole fraction of solute and the molal concentration for an aqueous solution that is 20.0% NaOH by mass?

never [62]

Let's assume we have 100 grams of this solution, and therefore 20.0 grams of NaOH, and 80.0 grams of water.

NaOH has a molar mass of 40.00 grams/mole, so we can convert NaOH to moles: (20.0 grams of NaOH) * (1 mole NaOH/40.00 grams NaOH) = 0.500 moles NaOH.

Next, we have a molar mass of water of 18.02 g/mol, so we can convert water to moles:

80.0 grams H2O * (1 mole H2O/18.02 grams) = 4.44 moles H2O
The mole fraction of NaOH is the moles of NaOH over the total moles of all parts of the solution. Therefore:

(0.500 moles NaOH)/(0.500 moles + 4.44 moles) = 0.101
0.101 = mole fraction of solute

The molal concentration is defined as the number of moles of solute over the number of kilograms of solvent (water).
We have 0.500 moles of NaOH, and 0.0800 kg of water, so it becomes:
(0.500 moles NaOH)/(0.0800 kg H2O solvent) = 6.25 molal solution

8 0

4 years ago