Teresa has taken three tests worth 100 points each. Her scores are 85, 93, and 88. She has one test left to take.

To get an average score of 90, what must the sum of all her test scores be?
a.
400
c.
600
b.
360
d.
300

Answer:

Option B clearly shows the Products of the reaction

Answer:

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Answer:

The required molar mass is 106.0 g/mol

Explanation:

We know,

Molar mass of Na = 23 g/mol

Molar mass of C= 12 g/mol

Molar mass of O= 16 g/mol

∴Molar mass of Na2CO3 = {(23 X 2) + 12+ (16 X 3)}  g/mol

                                          = (46 + 12 + 48) g/mol

                                          = 106   g/mol

So, the required molar mass is 106.0 g/mol

Answer:

Metal

Non-metal

Explanation:

Ionic compounds are said to be formed when metals donate electrons to non metals.

The metals become positively charged while the nonmetals become negatively charged.

CaF2 is composed of Ca^2+ and F^-. Calcium is a metal of group 2 in the periodic table while F is a nonmetal of group 17 in the periodic table.

Hence CaF2 is composed of a metal and a nonmetal.

You will get iron sulfate and hydrogen sulfide gas (a.k.a. rotten egg gas).

FeS + H2SO4 = FeSO4 + H2S(g)

Change in Free Energy: ΔG(20C) = -66.6kJ (negative, so the reaction runs)

Change in Enthalpy: ΔH(20C) = -37.3kJ (negative, so the reaction is exothermic)

We'll begin by writing the balanced equation for the reaction between ferrous sulphide (FeS) and sulphuric acid (H₂SO₄). This is illustrated below:

FeS + H₂SO₄ —> H₂S + FeSO₄

Next, we shall determine the mass of FeS that reacted and the mass of H₂S produced from the balanced equation. This is illustrated below:

Molar mass of FeS = 56 + 32

= 88 g/mol

Mass of FeS from the balanced equation = 1 × 88 = 88g

Molar mass of H₂S = (2×1) + 32

= 2 + 32

= 34 g/mol

Mass of H₂S from the balanced equation = 1 × 34 = 34 g

From the balanced equation above,

88 g of FeS reacted to produce 34 g of H₂S.

Finally, we shall determine the mass of H₂S produced by the reaction of 4.4 g of FeS. This can be obtained as follow:

From the balanced equation above,

88 g of FeS reacted to produce 34 g of H₂S.

Therefore, 4.4 g of FeS will react to produce = (4.4 × 34)/88 = 1.7 g of H₂S.

Thus, 1.7 g of H₂S were obtained from the reaction.

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Answer: According to reaction below, when one mol of oxygen reacts with two mol of hydrogen, two mol of water is produced. Thus, when 2.5 mol of oxygen reacted with hydrogen, 2 * 2.5 mol = 5 mol of water is produced. The molar mass of water is 18 g/mol.

Explanation:

Not My WORK!  I got this info from another site.  BUT I HOPE IT HELPS :)

Answer: The partial pressure of [tex]N_{2}O[/tex] is 0.35 atm.

Explanation:

Given: Total pressure = 0.98 atm

Partial pressure of [tex]O_{2}[/tex] = 0.48 atm

Partial pressure of Ar = 0.15 atm

Partial pressure of [tex]N_{2}O[/tex] = ?

Total pressure is the sum of partial pressure of each component present in a mixture of gases.

Hence, partial pressure of [tex]N_{2}O[/tex] is calculated as follows.

Total pressure = [tex]P_{N_{2}O} + P_{O_{2}} + P_{Ar}[/tex]

Substitute the values into above formula as follows.

[tex]Total pressure = P_{N_{2}O} + P_{O_{2}} + P_{Ar}\\0.98 atm = P_{N_{2}O} + 0.48 atm + 0.15 atm\\P_{N_{2}O} = 0.35 atm[/tex]

Thus, we can conclude that the partial pressure of [tex]N_{2}O[/tex] is 0.35 atm.

Answer:

5.83 g

Explanation:

First, you must start with a balanced equation so you can see the mole ratios.

NaOH + H₃BO₃ --> NaBO₂ + 2H₂O

You can see that it takes 1 mole of sodium hydroxide to form 1 mole of sodium borate. 1:1 ratio

Now you must calculate how many moles of NaOH 35.47 g equals.

Na = 22.99 amu

O = 15.99 amu

H = 1.008 amu

NaOH = 39.997 amu

35.47 g ÷ 39.997 amu = 0.08868 moles of NaOH

Since it's a 1:1 ratio, the same number of moles of NaBO₂ is created. Now you must convert moles to grams.

Na = 22.9 amu

B = 10.81 amu

2 O = 31.998 amu

NaBO₂ = 65.798 amu

0.08868 moles x 65.798 = 5.83 g

Answer: The molarity of solution will be 0.049 M

Explanation:

Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L. The formula used to calculate molarity:

[tex]\text{Molarity of solution}=\frac{\text{Given mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (L)}}[/tex]

We are given:

Given mass of sodium chloride = 10 g

Molar mass of sodium chloride = 58.44 g/mol

Volume of solution = 3.50 L

Putting values in above equation:

[tex]\text{Molarity of NaCl}=\frac{10 g}{58.44g/mol\times 3.50}\\\\\text{Molarity of NaCl}=0.049M[/tex]

Hence, the molarity of solution will be 0.049 M

sound energy is produced when particles vibrate. When an object vibrates, it causes movement in surrounding air molecules.

Answer:

2. much greater

The statement, that describes the energy released per mole of reactant during nuclear reactions is "much greater."

Nuclear reaction is a sort of reaction in which the structure of an atom's nucleus changes completely, frequently producing a different element while releasing energy.

The energy released by nuclei is far more dense (approximately a million times more dense) than the energy released by atom interactions (chemical reactions). This is what gives nuclear weapons their extraordinarily huge and destructive force when compared to conventional weapons. Nuclear reactions generate more energy than chemical reactions.

Hence the correct option is 2.

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Answer:

[tex]2C _{6}H _{14} + 19O _{2}→12CO _{2} +14H _{2} O[/tex]

Answer:

The correct answer is - sudden static charge could damage sensitive medical equipment.

Explanation:

Staff members of a hospital or medical institution wear special shoes that are able to prevent static charge as they walk. These shoes help to prevent static charge as we know that the sudden transfer of a static charge to medical equipment may alter the reports or damage sensitive equipment. This type of static charge is negative or positive due to electronic devices touches the device leads to damage of electric devices.

Thus, the correct answer is - sudden static charge could damage sensitive medical equipment.

Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite.

Answer:

pentene

Explanation:

pentene is 5 carbon chain with a double bond. The ending -ene indicates presence of double bond.

Answer:

71.92 kPa

Explanation:

Using the combined gas law equation;

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure (kPa)

P2 = final pressure (kPa)

V1 = initial volume (L)

V2 = final volume (L)

T1 = initial temperature (K)

T2 = final temperature (K)

According to the information provided in this question;

T1 = 50°C = 50 + 273 = 323K

V1 = 105L

T2 = -25°C = -25 + 273 = 248K

P2 = 105.4 kPa

P1 = ?

V2 = 55.0 L

Using P1V1/T1 = P2V2/T2

P1 × 105/323 = 105.4 × 55/248

105P1/323 = 5797/248

0.325P1 = 23.375

P1 = 23.375 ÷ 0.325

P1 = 71.92 kPa

Answer:

V2~0.4839M

Explanation:

We're going to use Boyles law to answer the question.

Boyle's law:

P1V1=P2V2

P1=151mmHg

P2=166mmHg

V1=0.532L

V2=?

V2=(P1 x V1)/P2

V2=(151 x 0.532)/166

V2~0.4839M

Hope it helps:)

Answer: C. unknown

Explanation: got it right on acellus

Answer:

ronger intermolecular forces will produce greater surface tension .

The intermolecular forces present in a sample of water are hydrogen bonds . The high surface tension of water allows a paper clip to "float" on the surface of the water. It's not actually floating, it's resting on top of the hydrogen bonds that exist between the water molecules at the surface. See the video below which shows a paper clip resting on the surface of water in a beaker.

If the hydrogen bonds are removed or disrupted, the surface tension will decrease. Watch what happens to the paper clip in the video when detergent (which will disrupt hydrogen bonds) is added to the beaker.

Here is video showing how a paperclip can "float" on water - it's actually being held up by the hydrogen bonds formed between water molecules which give water its surface tension.

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Answer:

If a one kilogram block of lead absorbs 2,000 J of energy then the temperature rise will be larger. If 1,000 J of heat is absorbed by a 2 kg block of lead then the temperature of the block doesn't rise as much since the energy is shared between more particles.

Explanation:

Answer: 300g

Explanation:

first we write the given values on top

224L. x

3 NO2 (g) + H2O (l) = 2HNO3 (l) + NO (g)

22.4L 30g

then we form a formula

224L/22.4L= x/30g

224*30/22.4

6720/22.4= 300g

Answer:

They live in the open snow

Explanation:

Explanation:Mg(s)+Zn(NO3)2(aq) → Mg(NO3)2(aq)+Zn(s)

Answer:

Thus,there are 0.2 mole in 8 g of calcium.

Answer:

The new pressure is equal to 1 atm.

Explanation:

Given that,

Initial pressure, P₁ = 3 atm

Initial volume, V₁ = 75cm³

Final volume, V₂ = 3V₁ = 225 cm³

We need to find the final pressure. The mathematical relation between P and V is :

[tex]P\propto \dfrac{1}{V}\\\\or\\\\\dfrac{P_1}{P_2}=\dfrac{V_2}{V_1}[/tex]

Where

V₂ is the new volume

So,

[tex]P_2=\dfrac{P_1V_1}{V_2}\\\\P_2=\dfrac{3\times 75}{225}\\\\P_2=1\ atm[/tex]

So, the new pressure is equal to 1 atm.

Answer:

1.2 mL

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated:

HCl + KOH —> KCl + H₂O

From the balanced equation,

Mole ratio of the acid, HCl (nₐ) = 1

Mole ratio of base, KOH (n₆) = 1

Finally, we shall determine the volume of the base, KOH needed to neutralize the acid, HCl as follow:

Molarity of base, KOH (M₆) = 0.997 M

Volume of acid, HCl (Vₐ) = 30 mL

Molarity of acid, HCl (Mₐ) = 0.0400 M

Volume of base, KOH (V₆) =?

MₐVₐ / M₆V₆ = nₐ/n₆

0.04 × 30 / 0.997 × V₆ = 1/1

1.2 / 0.997 × V₆ = 1

Cross multiply

0.997 × V₆ = 1.2

Divide both side by 0.997

V₆ = 1.2 / 0.997

V₆ = 1.2 mL

Thus, the volume of the base, KOH needed to neutralize the acid is 1.2 mL.

Answer:

greenhouse effect is the same as global warming

Explanation:

they both mean warming of the earths surface