If we start with 1.000 g of strontium-90, 0.908 g will remain after 4.00 yr This means that half-life of strontium-90 is _________ yr.

A) 3.05

B) 4.40

C) 28.8

D) 3.63

E) 41.6

Answer:

1.84 atm

Explanation:

P2=V1P1/V2

Temp is irrelevant because it is constant, so all you have to do is rearrange the ideal gas law.

You can check this by knowing P and V at constant T have an inverse relationship and therefore makes this the correct answer.

- Hope that helps! Please let me know if you need further explanation.

Answer:

A

Explanation:

Unlike the female reproductive system, the most parts of the male reproductive system are located outside the body. The mentioned part in the given diagram is urethra and it Mixes sperm and semen. The correct option is A.

The male reproductive system includes the testes, scrotum, spermatic ducts, male accessory glands and phallus. All these organs work together to produce sperms, the male gamete, male sex hormones and other components of semen.

The phallus and urethra are the parts of both the reproductive and urinary systems. Scrotum, seminal vesicles, vas deferens, testicles and prostate constitute all the remaining male reproductive system.

The urethra is a tube like structure which is the region included in the urinary tract that takes the urine from the bladder where the semen is ejaculated.

Thus the correct option is A.

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Answer:

all of them except number 2

Explanation:

Answer:

1,3,4,5  the other perosn is correct

Explanation: That what my quiz said

Answer:

The answer is NaOH

Explanation:

Strong bases are characterized by the fact that they dissociate completely in an aqueous solution. In this case, sodium hydroxide, NaOH, is classified as a strong base because it dissociates completely in an aqueous solution to form sodium cations, Na+, and hydroxide anions, OH−. Also, it is strong because it totally breaks in its ion. And the base which breaks totally in its atom called the strong base and which doesn't it that is a weak base.

Answer:

NaOH

Explanation:

Got it right in the test. Please mark as brainliest

Answer:

Before submerged 150ml

After submerged: 180ml

rock volume: [tex]180 - 150 = 30[/tex]

formula for density:

[tex] \frac{mass}{volume} = 5.38 [/tex]

[tex] \frac{175}{30} = 5.38 [/tex]

THE ANSWER IS b

prettty sure this is wrong but eh :/ probably correct

Answer:

Option C

Explanation:

Dipole moment being ac vector quantity has both magnitude and direction. All bonding forces have dipole moment ranging from partially positive to negative moment.  

Net dipole moment is the dipole moment arising after summation of all the existing dipole moments. On the basis of dipole moment it is determined whether the molecule is polar or non polar.  

Hence, option c is correct

Answer:c

Explanation:

Answer:

1 quart of lemonade will be in the first cup

Explanation:

1/4th of a gallon is a quart

Answer:

D. Wind Speed

Explanation:

When the question brings up 35 m/h, the m/h stands for Miles per Hour. What option can you measure the miles per hour. Here's a hint, it applies to cars as well when cops give your parents speeding tickets. Miles per Hour = Speed. So, you are measuring the wind speed.

Answer:

D. using a solid with a high surface area in the reactants, is your correct answer.

Explanation:

Using a solid with a high surface area in the reactants is usually associated with a higher reaction rate.

Answer:

Lewis acids cannot have a hydroxide or hydrogen ion or donate a hydrogen ion, so they are neither an Arrhenius or a Brønsted-Lowry acid or base. Lewis bases will always be Brønsted-Lowry bases because they can accept a hydrogen ion.

According to Lewis concept ,Lewis acids cannot have hydroxide or hydrogen ion or donate a hydrogen ion, so they are neither an Arrhenius or a Brønsted-Lowry acid or base. Lewis bases will always be Brønsted-Lowry bases because they can accept a hydrogen ion.

According to Lewis concept, Lewis dot structures are also called as electron dot structures and can be drawn if the molecular formula of a compound is known. It provides information regarding the nature of bond and the position of atoms .

They are also capable of exhibiting the lone pair if any present in a molecule or compound.Lewis defined a base to be an electron pair donor and an acid to be an electron pair acceptor.

They are capable of reflecting electronic structure of elements and even the pairing of electrons . In the diagram, each dot represents an electron while a pair of dots represent a bond between the atoms.

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The molarity of a KCl solution if 37.3 g of KCl are dissolved in water to give a final solution volume of 500 ml is 1 M.

Molarity of a given solution is known as the total number of moles of solute per litre of the solution.  A solution that is 1.00 molar (written 1.00 M) contains 1.00 mole of solute for every liter of solution.

Molarity = (No. of moles of solute ÷ Volume of solution in liters)

The unit of molarity is mol L⁻¹.

Molarity is temperature dependent because as temperature changes, volume of the solution also changes.

Given, Mass of KCl = 37.3 g

Molar mass of KCl = 74.5 g/mol

Volume of solution = 500ml = 0.5 L

No. of moles = Mass / Molar mass = 0.5

Molarity = 0.5/0.5 = 1 M

Therefore, The molarity of a KCl solution if 37.3 g of KCl are dissolved in water to give a final solution volume of 500 ml is 1 M.

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Answer:

The planets themselves are composed of several trillions or quadrillions or more atoms. As far as hard science is concerned, it would be really hard to picture them as electrons. Conclusion: It can be said with a great accuracy that our planets are NOT huge electrons.

Rutherford's experiments showed that the mass of atoms was mostly concentrated in a very small region, with charge equal to the atomic number- the nucleus. He absolutely did not show, nor is it true, that electrons orbit the nucleus as if they were planets. That was a guess people made in trying to figure out how to picture the atom.

(Hope this helps) Sky

Answer:

The equilibrium concentration of gas A is 1.43 M

Explanation:

Here we have the reaction expressed as follows;

A + B → C + D and

The formula for equilibrium constant is therefore presented as follows;

[tex]K = \frac{[C]\times [D]}{[A]\times [B]}[/tex]

Where:

[C] = [D] = 2.3 M

[A] = [B]

K = 2.6

Hence, we have;

[tex]2.6 = \frac{2.3\times 2.3}{[A]\times [A]} = \frac{5.29}{[A]^2}[/tex]

[tex][A]^2= \frac{5.29}{2.6} = 2.03[/tex]

[A] = 1.43 M

The equilibrium concentration of gas A = 1.43 M.

Answer:

The equilibrium concentration of gas A = 1.43 M

Explanation:

First set up the equilibrium expression:

[tex]K = \frac{[C]\times [D]}{[A]\times [B]}[/tex]

The problem states that each product has a concentration of 2.3M at equilibrium, and that k=2.6

We also know that [A] and [B] are the same.

Since we are solving for [A] I'm going to change [A][B] to A²

[tex]2.6 =\frac{2.3^2}{A^2}[/tex]

Now we just need to solve for A²

A² = 5.29 / 2.6

A² = 2.0346

A = √2.0346

A = 1.43

Therefore, the equilibrium concentration of gas A = 1.43 M.

Answer: The air pressure at the top of the mountain is 96.9 kPa

Explanation:

To calculate the new pressure, we use the equation given by Boyle's law. This law states that pressure is directly proportional to the volume of the gas at constant temperature.

The equation given by this law is:

[tex]P_1V_1=P_2V_2[/tex]

where,

[tex]P_1\text{ and }V_1[/tex] are initial pressure and volume.

[tex]P_2\text{ and }V_2[/tex] are final pressure and volume.

We are given:

[tex]P_1=99.5kPa\\V_1=22.3L\\P_2=?\\V_2=22.9L[/tex]

Putting values in above equation, we get:

[tex]99.5\times 22.3L=P_2\times 22.9L\\\\P_2=96.9kPa[/tex]

Thus the air pressure at the top of the mountain is 96.9 kPa

Answer: Pounds per Cubic inch(lb/in3)

Answer:

[tex]\rm _{27}^{60}\text{Co} \longrightarrow \, _{-1}^{0}\text{e} + \, _{28}^{60}\text{Ni}[/tex]

Explanation:

The unbalanced nuclear equation is

[tex]\rm _{27}^{60}\text{Co} \longrightarrow \, _{-1}^{0}\text{e} + \, ?[/tex]

Let's write the question mark as a nuclear symbol.

[tex]\rm _{27}^{60}\text{Co} \longrightarrow \, _{-1}^{0}\text{e} + \, _{Z}^{A}\text{X}[/tex]

The main point to remember in balancing nuclear equations is that the sums of the superscripts and the subscripts must be the same on each side of the equation.  

Then

60 = 0 + A, so A = 60 - 0 = 60, and

27 = -1 + Z, so Z  = 27 + 1 = 28

Your nuclear equation becomes

[tex]\rm _{27}^{60}\text{Co} \longrightarrow \, _{-1}^{0}\text{e} + \, _{28}^{60}\text{X}[/tex]

Element 28 is nickel, so the balanced nuclear equation is

[tex]\rm _{27}^{60}\text{Co} \longrightarrow \, _{-1}^{0}\text{e} + \, _{28}^{60}\text{Ni}[/tex]

Answer:

ionic

Explanation:

Winds are always named from the direction it blows from

Uneven heating of Earth's surface,in turn,causes differences in air pressure at various locations. Heated air rises,creating an area of low pressure beneath. Cooler air descends, creating an area of high pressure

Answer:

Explanation:

Hb(CO)4(aq) + 4O2(g)  ⇄  Hb(O2)4(aq) + 4CO(g)

1 )  If we increase the concentration of CO(g) , the reaction above will proceed in reverse direction to decrease its concentration,  according to Le Chatelier principle. Hence more of Hb(CO)4(aq) will be formed.

2 )  If we decrease the concentration of O₂ , then also , reaction will proceed in reverse direction . Hence concentration of Hb(CO)4(aq) will be increased .

Answer:

D working alone

Explanation:

Working alone is the only option that could potentially be a safety hazard; if you have no one watching your back, errors could occur, like dropping glass or burning your hand, and no one is around to help you.

Choices A, B, and C are not correct because those are all good safety standards.

Answer:

Approximately [tex]-74.8\; \rm kJ \cdot mol^{-1}[/tex].

Explanation:

Number the three reactions with known enthalpy changes:

[tex]\begin{aligned}& {\rm C\; (s) + O_2\; (g) \to CO_2\; (g)} & \quad \Delta H = -393.5\; \rm kJ\cdot mol^{-1}& \quad (1) \\ & {\rm H_2\; (2) + \frac{1}{2} O_2\; (g) \to H_2O\; (l)} & \quad \Delta H = -285.8\; \rm kJ\cdot mol^{-1} & \quad (2) \\ & {\rm CH_4\; (g) + 2\; O_2\; (g) \to CO_2\; (g) + 2\; H_2O\; (l)} & \quad \Delta H = -890.3\; \rm kJ\cdot mol^{-1} & \quad (3)\end{aligned}[/tex].

The goal is to find a way to combine these three reactions to obtain: [tex]\rm C\; (s) + 2\; H_2\; (g) \to CH_4\; (g)[/tex].

Assume that the three known reactions are combined in this way:

[tex]a \times (1) + b \times (2) + c \times (3)[/tex].

That corresponds to:

[tex]\begin{aligned} & a\; \mathrm{C\; (s)} + \left(a + \frac{1}{2}\, b + c\right) \; \mathrm{O_2\; (g)} + b\; \mathrm{H_2\; (g)} + c\; \mathrm{CH_4\; (g)} \\ & \to (a + c)\; \mathrm{CO_2\; (g)} + (b+ 2\,c )\; \mathrm{H_2O\; (l)}\end{aligned}[/tex].

Compare the coefficients of this reaction with that of the desired reaction:

[tex]\rm C\; (s) + 2\; H_2\; (g) \to CH_4\; (g)[/tex].

Note that some species (e.g., [tex]\rm CH_4\; (g)[/tex]) appeared on the wrong side of the equation. Their desired coefficient should be the opposite of their true coefficient. For example, the coefficient of [tex]\rm CH_4\; (g)[/tex] is supposed to be [tex]1[/tex]. However, because it appeared on the wrong side of the equation, its desired coefficient would be [tex]-1[/tex].

The coefficients of species that are not in the desired equation should be zero.

[tex]\begin{array}{|c|c|c|}\cline{1-3}\text{Species} & \text{Coefficient}& \text{Desired Coefficient} \\ \cline{1-3} \mathrm{C\; (s)}} & a & 1 \\ \cline{1-3} \mathrm{O_2\; (g)} & a + (1/2)\, b + c & 0 \\ \cline{1-3} \mathrm{H_2\; (g)} & b & 2 \\ \cline{1-3}\mathrm{CH_4\; (g)} & c & -1\\ \cline{1-3} \mathrm{CO_2\; (g)} & a + c & 0 \\ \cline{1-3} \mathrm{H_2O\; (l)} & b + 2\, c & 0\\ \cline{1-3}\end{array}[/tex].

Solve for [tex]a[/tex], [tex]b[/tex], and [tex]c[/tex]:

In other words, the desired equation is equal to [tex]1 \times (1) + 2 \times (2) - 1 \times (3)[/tex].

By Hess's Law, the enthalpy of the desired equation will be:

[tex]\begin{aligned}& 1\times \Delta H (1) + 2 \times \Delta H (2) - 1\times \Delta H(3) \\ &\approx -393.5 + 2 * (-285.8) - (-890.3) \\ &= -74.8\; \rm kJ \cdot mol^{-1} \end{aligned}[/tex].

Answer:

The correct answer is The pressure of the gas will increase

The volume of the gas will increase

Explanation:

Step 1: Data given

The gas in a container is heated, this means the temperature increases

Suppose we start with a temperature of 100 K and a pressure of 1 atm and a volume of 1L

Step 2:

V1/T1= V2/T2

⇒V1 = the initial  volume = 1L

⇒T1 = the initial temperature = 100 K

⇒V2 = the new volume = TO BE DETERMINED

⇒T2 = the increased temperature = 200 K

1/100 = V2 / 200

V2 = 2 L

This means when the temperature increases, the volume will increase

P1/T1 = P2/T2

⇒P1 = the initial pressure = 1 atm

⇒T1 = the initial temperature = 100 K

⇒P2 = the new pressure = TO BE DETERMINED

⇒T2 = the increased temperature = 200 K

1/100 = P2 / 200

P2 = 2 atm

This means when the temperature increases, the pressure will increase

The correct answer is The pressure of the gas will increase

The volume of the gas will increase

Answer:

C:

Explanation:

Current flows from negative to positive.So the electrons will be moving left.

when a current is applied, positive charged copper ions (called cations) leave the anode (positive electrode) and move to the cathode (negative electrode).

Answer:

[tex]\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e + \, _{39}^{91}Y[/tex]

Explanation:

The unbalanced nuclear equation is

[tex]\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e \, + \, ?[/tex]

Let's write the question mark as a nuclear symbol.

[tex]\rm _{38}^{91}Se} \longrightarrow \, _{-1}^{0}e \, + \, _{Z}^{A}X[/tex]

The main point to remember in balancing nuclear equations is that the sums of the superscripts and the subscripts must be the same on each side of the equation.  

Then

98 =  0 + A, so A =  98 -  0 = 98, and

38 = -1 + Z, so Z  = 38 + 1 = 39

Then, your nuclear equation becomes

[tex]\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e + \, _{39}^{91}X[/tex]

Element 39 is yttrium, so the balanced nuclear equation is

[tex]\rm _{38}^{91}Sr \longrightarrow \, _{-1}^{0}e + \, _{39}^{91}Y[/tex]

Answer:

object a will float higher because it has less density.

Explanation:

Answer:

object a will float higher because it has less density.

Explanation:

Answer:

Photo chemical is caused by the chemical reaction of light. It's initiated by the absorption of energy in the form of light.

Explanation:

When the picture is developed, the thiosulfate dissolved the silver bromide that had been exposed to light more easily than the one that had been kept in the dark,

Answer:

CaC2 + 2H2O > C2H2 + Ca(OH)2

Explanation:

Count the amounts of Ca, C, H, and O, all separately on both sides.

Ca: 1                     Ca: 1

C: 2                      C:2

H: 2                      H: 4

O: 1                       O: 2

Now, your goal is to get both sides equal to each other by adding a 2 in front of H2O.

Answer:

M=0.02

Explanation:

85 g NaNO3  -> 1 mol NaNO3

0.45 g NaNO3 ->x

x=(0.45 g NaNO3 * 1 mol NaNO3)/85 g NaNO3       x= 5.3 x 10^-3 mol

265 mL= 0.265 L

M= mol solute/ L solution

M= 5.3 x 10^-3 mol NaNO3/0.265 L            M=0.02