Which of the following is produced when two or more elements combine in a chemical reaction?

Jailah needs a replacement for lithium for a science experiment. She tries silicon, but it does not work. Using what you know ab

pentagon [3]

Answer:

C

Explanation:

6 0

3 years ago

2HCl + CaCO3 → CaCl2 + H2O + CO2

zloy xaker [14]

Answer:

The amount of CaCl2 produced depends on the amount of HCl in the reaction.

Explanation:

The amount of HCl is used completelyin the reaction unlike CaCO3 which remains after reaction.

4 0

3 years ago

Why are atoms more stable when combined?

shepuryov [24]

Answer:

D

Explanation:

3 0

3 years ago

How many moles of sodium carbonate contain 1.773 × 1017 carbon atoms?

vesna_86 [32]

Answer:

2.941 × 10⁻¹⁷ mol

Explanation:

1) Chemical formula of sodium carbonate: Na₂CO₃

2) Ratio of carbon atoms:

The number of atoms of C in the unit formula Na₂CO₃ is the subscript for the atom, which is 1 (since it is not written).

Hence, the ratio is 1 C atom / 1 Na₂CO₃ unit formula.

This is, there is 1 atom of carbon per each unit formula of sodium carbonate.

3) Calculate the number of moles in 1.773 × 10⁷ carbon atoms

Divide by Avogadro's number: 6.022 × 10²³ atoms / mol

number C moles = 1.773 × 10⁷ atoms / (6.022 × 10²³ atoms/mol)

number C moles = 2.941 × 10⁻¹⁷ mol

Since, the ratio is 1: 1, the number of moles of sodium carbonate is the same number of moles of carbon atoms.

5 0

3 years ago

Calculate the molarity of a solution obtained dissolving 10.0 g of cobalt(Ⅱ) bromide tetrahydrate in enough water to make 450 mL

Vladimir [108]

Answer:

The molarity of the CoBr2•4H2O solution is 7.64 × 10-2 M

Explanation:

Cobalt (II) bromide tetrahydrate

• Cobalt - A transition metal with Roman numeral (II) → charge: +2 → Co2+

• Bromide - anion from group 7A → -1 charge → symbol: Br-

• Tetrahydrate- tetra- means 4 and hydrate is H2O

The chemical formula of the compound is: CoBr2•4H2O

We then need to determine the number of moles of CoBr2•4H2O since this is the only information missing for us to find molarity. Notice that the volume of the solution is already given.

We’re given the mass of CoBr2•4H2O. We can use the molar mass of CoBr2•4H2O4 to find the moles.

•The molar mass of CoBr2•4H2O is:

CoBr2•4H2O

1 Co x 58.93 g/mol Co = 58.93 g/mol

2 Br x 79.90 g/mol Br = 159.80 g/mol

8 H x 1.008 g/mol H = 8.064 g/mol

4 O x 16.00 g/mol O = 64.00 g/mol

________________________________________

Sum = 290.79 g/ mo

The moles of CoBr2•4H2O is:

= 10.0 g CoBr2•4H2O x $\frac{ 1 mol CoBr_2 . 4H_2O}{290.79 g CoBr_2 . 4H_2O}$

= 0.0344 mol CoBr2•4H

We know that the volume of the solution is 450 mL.

We can now calculate for molarity:

Convert mL to L → 1 mL = 10-3 L

Formula:

Molarity (M)= Mole of solute / Liters of solution

= 0.0344 mol CoBr2•4H / 450 mL x 1 ml / 10^ -3 L

= 0.0764

= 7.64 × 10-2 mol/L

8 0

3 years ago