Which of the following black body curves is representative of stars like our sun?

a total of 1.4 moles of sodium nitrate is dissolved in enough water to make 2.0 liters of an aqueous solution. the gram-formula

kompoz [17]

Answer:

1.4 moles/ 2.0 L= 0.7 M

Explanation: Molarity= moles of solute/ Liters of solution

therefore just plug the numbers in and you'll find the molarity to equal. 0.7

7 0

2 years ago

Dissolving brass requires an oxidizing acid such as concentrated nitric acid. Nitrogen dioxide is produced as a byproduct in thi

polet [3.4K]

Answer:

Cu + 4 HNO₃ → Cu(NO₃)₂ + 2 NO₂ + 2 H₂O

Explanation:

Step 1: Write down the chemical formulas of given substances,

Copper Metal = Cu

Nitric Acid = HNO₃

Copper (II) Nitrate = Cu(NO₃)₂

Nitrogen Dioxide = NO₂

Water = H₂O

Step 2: Write down the unbalance Chemical equation,

Cu + HNO₃ → Cu(NO₃)₂ + NO₂ + H₂O

Step 3: Balance Cu atoms on both sides;

The number of Cu atoms on both sides are same. Hence, there number will remain the same.

Step 4: Balance N atoms on both sides;

As there is 1 N atom on left hand side and 3 N atoms on right hand side, so we will multiply HNO₃ by 3 to balance N on both sides, hence,

Cu + 3 HNO₃ → Cu(NO₃)₂ + NO₂ + H₂O

Step 5: Balance O atoms on both sides;

As there are 9 O atom on left hand side and 9 O atoms on right hand side, so they are balance.

Step 6: Balance H atoms on both sides;

As there are 3 H atom on left hand side and 2 H atoms on right hand side, so we will multiply H₂O by 2 as,

Cu + 3 HNO₃ → Cu(NO₃)₂ + NO₂ + 2 H₂O

By doing so the number of O atoms got imbalanced, so to balance O atoms again we will multiply HNO₃ by 4 as,

Cu + 4 HNO₃ → Cu(NO₃)₂ + NO₂ + 2 H₂O

Now, The Cu and H atoms are balanced, and the O atoms are greater on left hand side and the N atoms are greater on right hand side, therefore we will multiply NO₂ by 2 to balance both N and O as,

Cu + 4 HNO₃ → Cu(NO₃)₂ + 2 NO₂ + 2 H₂O

7 0

3 years ago

In one experiment, magnesium metal melts. In a second experiment, magnesium metal ignites as it combines with oxygen. Classify t

joja [24]

Answer:

magnesium metal melts = physical change

magnesium metal ignites = chemical change

Explanation:

Physical changes are those in which the identity of the subtance remains unaltered. No new compounds are formed. They involve generally changes in agreggation states of matter: solid, liquid or gas. The first experiment, in which magnesium metal melts is a physical change because it only changes the state of matter, from solid to liquid, but it is still magnesium metal.

Conversely, chemical changes involve atoms combinations to form new compounds. The second experiment, in which magnesium metal ignites, is a chemical change. After the change, magnesium metal is no longer the metal but a metal oxide.

8 0

3 years ago

I need help with this please

jarptica [38.1K]

Answer: the place that i put the letters is how it should look also 75% of your peas are green

Explanation:

3 0

3 years ago

Lead (ll) nitride+ammonium sulfate > lead(ll) sulfate + ammonium nitride

Alenkinab [10]

Answer:

$Pb_3N_2 + 3 (NH_4)_2SO_4\rightarrow 3 PbSO_4 + 2 (NH_4)_3N$

Explanation:

Let's rewrite the given word equation in its chemical balanced equation representation:

1. Lead(II) nitride is represented by lead, Pb, in an oxidation state of 2+, while nitride is a typical nitrogen anion with a state 3-. As a result, the lowest common multiple between 2 and 3 is 6, meaning 2 lead cations are needed to balance 3 nitrogen anions: $Pb_3N_2$ .

2. Ammonium sulfate consists of an ammonium cation with a 1+ charge and sulfate anion with a 2- charge, two ammonium cations needed: $(NH_4)_2SO_4$ .

3. Lead(II) sulfate would have one lead cation and one sulfate anion, as they have the same magnitude of charges with opposite signs: $PbSO_4$ .

4. Ammonium nitride would require three amonium cations to balance the nitride anion: $(NH_4)_3N$ .

Let's write the balanced equation:

$Pb_3N_2 + 3 (NH_4)_2SO_4\rightarrow 3 PbSO_4 + 2 (NH_4)_3N$

7 0

4 years ago